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British Journal of Anaesthesia
BJA

Aerosol boxes and barrier enclosures for airway management in COVID-19 patients: a scoping review and narrative synthesis

Open ArchivePublished:September 03, 2020DOI:https://doi.org/10.1016/j.bja.2020.08.038

      Summary

      Exposure of healthcare providers to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a significant safety concern during the coronavirus disease 2019 (COVID-19) pandemic, requiring contact/droplet/airborne precautions. Because of global shortages, limited availability of personal protective equipment (PPE) has motivated the development of barrier-enclosure systems, such as aerosol boxes, plastic drapes, and similar protective systems. We examined the available evidence and scientific publications about barrier-enclosure systems for airway management in suspected/confirmed COVID-19 patients. MEDLINE/Embase/Google Scholar databases (from December 1, 2019 to May 27, 2020) were searched for all articles on barrier enclosures for airway management in COVID-19, including references and websites. All sources were reviewed by a panel of experts using a Delphi method with a modified nominal group technique. Fifty-two articles were reviewed for their results and level of evidence regarding barrier device feasibility, advantages, protection against droplets and aerosols, effectiveness, safety, ergonomics, and cleaning/disposal. The majority of analysed papers were expert opinions, small case series, technical descriptions, small-sample simulation studies, and pre-print proofs. The use of barrier-enclosure devices adds to the complexity of airway procedures with potential adverse consequences, especially during airway emergencies. Concerns include limitations on the ability to perform airway interventions and the aid that can be delivered by an assistant, patient injuries, compromise of PPE integrity, lack of evidence for added protection of healthcare providers (including secondary aerosolisation upon barrier removal), and lack of cleaning standards. Enclosure barriers for airway management are no substitute for adequate PPE, and their use should be avoided until adequate validation studies can be reported.

      Keywords

      • Airway management in patients with COVID-19 carries the risk of aerosol and droplet transmission of the virus.
      • Shortages of personal protective equipment have prompted the development of many novel barriers to reduce the risk to practitioners.
      • Evidence for the effectiveness of these barriers is currently lacking, and some studies suggest that they may hinder airway management, bringing additional risk.
      • Before ‘airway management isolation boxes’ (and other barriers) can be recommended for widespread clinical use, further study in the simulation and clinical environments is needed.
      According to Greek mythology, when Prometheus stole fire from the gods, Zeus took his revenge by introducing Prometheus's brother, Epimetheus, to Pandora. This curious lady opened a box she had been given for safekeeping, thereby unleashing disease, death, and uncountable evils into the world.
      Since then, ‘Pandora's box’ has become an idiom representing ‘any source of great and unexpected troubles’ or ‘a present which seems valuable, but which in reality is a curse’.
      • Wikipedia
      Pandora’s box.
      Coronavirus disease 2019 (COVID-19) may not have been one of the maladies contained in Pandora's box, but the pandemic provides an opportunity to discuss similar mysterious new coffers.
      Regional shortages of personal protective equipment (PPE) have triggered concerns regarding the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by respiratory droplets and aerosols during airway management. A large number of aerosol boxes, plastic covers, tents and sheets, and similar barrier-enclosure systems have been proposed to augment or adjunct PPE. None of these barrier devices have undergone rigid evaluation and validation. This review aims to highlight the features of the variously proposed solutions, and discuss limitations, potential pitfalls, and dangers related to their use as tools to prevent healthcare provider (HCP) contamination and infection during airway management.

      Search methods

      A literature review was performed in MEDLINE, Embase, and Google Scholar databases, including publications from December 1, 2019 to May 27, 2020. Articles pertaining to barrier enclosures for airway management in the context of COVID-19 in any language were retrieved. The search strategy used included the following search terms: ‘(((COVID OR COVID-19 OR coronavirus) AND (airway OR airway management OR intubation) AND (aerosol box OR intubation box OR airway box OR barrier enclosure OR tent OR barrier OR sheet OR protection OR shield OR drape OR aerosol-generating procedure OR droplet OR safety))) AND (’2019/12/01’ [Date - Publication]: ‘3000’ [Date - Publication])’ (Supplementary Appendix 2). A hand search of references cited in the selected papers was performed by an expert panel. An additional Google search was undertaken to identify grey literature evidence and online guidelines of scientific societies; pre-print articles; and relevant documents published by governmental or healthcare agencies, professional associations, and medical educators and innovators.
      Irretrievable full-text reports; data referring to outbreaks caused by non-COVID-19-causing pathogens; and articles available in languages other than English, French, Spanish, Italian, and German were excluded. As a scoping review, this study was conducted in accordance with published standards.
      • Tricco A.C.
      • Lillie E.
      • Zarin W.
      • et al.
      PRISMA extension for scoping reviews (PRISMA-ScR): checklist and explanation.
      ,
      • Peters M.D.
      • Godfrey C.M.
      • Khalil H.
      • McInerney P.
      • Parker D.
      • Soares C.B.
      Guidance for conducting systematic scoping reviews.

      Findings

      The database search returned 109 papers, with an additional 32 publications (including six websites) found on manual search. Two papers were eliminated as duplicates. Applying inclusion and exclusion criteria, 87 papers were removed. A total of 52 articles and six websites were included in this review (Fig 1 and Supplementary Appendix 1). All documents were reviewed by the expert panel and assessed for article type, study design, type of barrier (intervention), sample size, study setting, a summary of interventions (outcomes), main findings, and relevance (Table 1). A narrative synthesis was drafted and referenced. The final result was obtained through a discussion with a modified Delphi method using a modified nominal group technique (mNGT). Given the limitations imposed by the pandemic lockdown and geographical distances, all mNGT discussion rounds (literature search, definitions of questions, literature selection, literature comparison and evaluation, and elaboration of conclusions and statements) were performed virtually using e-mail, WhatsApp (https://www.whatsapp.com), and Zoom (https://www.zoom.us) platforms during a 6 week time span.
      Fig 1
      Fig 1Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow diagram of the study.
      Table 1Characteristics of the reviewed reports. List and study characteristics of all references included in the review (see Methods for detail). AB, aerosol box; COVID-19, coronavirus disease 2019; CPD, clear plastic drape; CPR, cardiopulmonary resuscitation; CPS, clear plastic sheet; ENT, ear, nose, and throat; FDA, Food and Drug Administration; LMA, laryngeal mask airway; N/A, not available; OT, operating theatre; PeDI-C, Pediatric Difficult Intubation Collaborative; PPE, personal protective equipment; SAD, supraglottic airway device; VLS, videolaryngoscope.
      ReferenceArticle typeStudy designType of barrierSample sizeStudy settingSummary of interventionsMain findings
      Canelli and colleagues
      • Canelli R.
      • Connor C.W.
      • Gonzalez M.
      • Nozari A.
      • Ortega R.
      Barrier enclosure during endotracheal intubation.
      CorrespondenceSimulated cough and investigated contamination of the laryngoscopistAcrylic ABTwo (case + control)Simulated cough on mannequin and investigated contamination of the laryngoscopist with or without ABApplication of ABAB minimises large droplet diffusion.
      Cubillos and colleagues
      • Cubillos J.
      • Querney J.
      • Rankin A.
      • Moore J.
      • Armstrong K.
      A multipurpose portable negative air flow isolation chamber for aerosol-generating procedures during the COVID-19 pandemic.
      CorrespondenceDescription of barrier-enclosure systemRigid plastic frame + plastic bag + vacuumN/A (1 simulation–12 operators?)Not specified tests (qualitative assessment of clearance of fluorescein tracer, and contamination of the operator, bag, table, and support structures)Barrier-enclosure system for intubationDuring a simulated airway management training session of our COVID-19 intubation team, direct vision, communication, and manoeuvrability were accomplished for 12 operators.
      Fonseca and colleagues
      • Fonseca E.O.
      • Blanco H.
      • Alvernia J.E.
      New design for aerosol protection during endotracheal intubation in the coronavirus disease 2019 (COVID-19) pandemic era: the “Anti-Aerosol Igloo” (AAI).
      CorrespondenceTechnical descriptionAnti-Aerosol Igloo (polyethylene terephthalate + CPS)N/ASimulation; case series (not described)Description of the enclosure barrierSeamless, single-piece element shaped like an igloo; easy to clean; lightweight; given the shape, minimal aerosol escape
      Rahmoune and colleagues
      • Rahmoune F.C.
      • Ben Yahia M.M.
      • Hajjej R.
      • Pic S.
      • Chatti K.
      Protective device during airway management in patients with coronavirus disease 2019 (COVID-19).
      CorrespondenceClinical reportRecycled neonatal incubator hoodN/AUnspecified tests on patients in OT/ICUApplication of recycled neonatal incubator hood for airway managementIntubation feasible, robust, economic; disadvantage: weight, some movements relatively limited
      Lai and Chang
      • Lai Y.Y.
      • Chang C.M.
      A carton-made protective shield for suspicious/confirmed COVID-19 intubation and extubation during surgery.
      CorrespondenceClinical reportCarton AB + plastic wrapN/AN/AApplication of carton/plastic AB for airway managementEconomic; limited visibility; patient's discomfort
      Au Yong and Chen
      • Au Yong PS.
      • Chen X.
      Reducing droplet spread during airway manipulation: lessons from the COVID-19 pandemic in Singapore.
      CorrespondenceExperimental reportPlastic tent/screenN/AHuman volunteer simulationsApplication of plastic tent/screen for intubation and extubationLow cost, easy availability, and disposability; room for VLS and bougie
      Lim and colleagues
      • Lim W.Y.
      • Wong P.
      • Ong S.G.K.
      Reducing droplet spread during airway manipulation. Reply to Au Yong and colleagues (Br J Anaesth 2020; 125: e176–e178).
      Correspondence in response to research letterCommentaryPlastic tent/screenN/AN/AApplication of plastic tent/screen for intubation and extubationConcerns for claustrophobia, secondary aerosolisation, impingement of airway devices
      Yang and colleagues
      • Yang S.S.
      • Zhang M.
      • Chong J.J.R.
      Comparison of three tracheal intubation methods for reducing droplet spread for use in COVID-19 patients.
      CorrespondenceSimulation studyABN/A (single test?)Comparison of tracheal intubation with direct laryngoscopy, VLS, and VLS + acrylic AB; measurement of trajectory and amount of droplet spread (atomiser model) in airway mannequin (detection system not detailed)Effect of AB on trajectory and amount of generated dropletsLaryngoscopy: large amount of dye on the laryngoscopist's face shield, gown, arms, glove, neck, and hair; VLS: significantly lower amount of dye on the laryngoscopist in similar locations, visually less than half the quantity than direct laryngoscopy; VLS + AB: dye only on the gloves and forearms within the box; no dye on any part of the laryngoscopist located outside the box, including gown, face shield, neck, and hair; AB is additional protection against droplets, although redundant if proper PPE are used
      Matava and colleagues
      • Matava C.T.
      • Yu J.
      • Denning S.
      Clear plastic drapes may be effective at limiting aerosolization and droplet spray during extubation: implications for COVID-19.
      CorrespondenceSimulation studyCPDSingle series of two experimentsAssessing if CPD contains aerosolisation during extubation with simulated cough by use of fluorescent resin powder with particle sizes between 1 and 5 μm with UV light detection in a darkened OTSimulated extubation and coughing: measurement without (Exp. 1A) and with (Exp. 1B) a single CPD applied over the head and tracheal tube; second experiments (Exp. 2) using a modified three-layer CPD configurationUse of a single CPD (Exp. 1B) restricted the aerosolisation and droplet spraying of the particles; the three-drape technique (Exp. 2) significantly reduced contamination of the immediate area surrounding the patient; limitation: dye droplets much larger than aerosolised droplets
      Malik and colleagues
      • Malik J.S.
      • Jenner C.
      • Ward P.A.
      Maximising application of the aerosol box in protecting healthcare workers during the COVID-19 pandemic.
      CorrespondenceSimulation study (?)AB + CPSN/A; report of ‘trials’ (in mannequin? not described)Modification of AB, including CPS proposed for airway management, including extubation, tracheostomy, tube exchange, gastric tube placement, patient transferUse of AB + CPS for airway managementImproved ergonomics, visibility, and room for instrumentation; ramped position possible; side ports; discouraged for emergency, vigilance to avoid PPE disruption
      Cordier and colleagues
      • Cordier P.Y.
      • De La Villeon B.
      • Martin E.
      • Goudard Y.
      • Haen P.
      Health workers’ safety during tracheostomy in COVID-19 patients: homemade protective screen.
      CorrespondenceClinical reportExternal fixator wrapped with a single-use clear surgical C-arm plastic coverN/AN/AApplication of barrier enclosure for tracheostomy and cannula exchangeTracheostomy feasible
      Zeidan and colleagues
      • Zeidan A.
      • Bamadhaj M.
      • Al-Faraidy M.
      • Ali M.
      Videolaryngoscopy intubation in patients with COVID-19: how to minimize risk of aerosolization?.
      CorrespondenceCase reportPlastic AB1Case report of single intubationPlastic AB placed after induction, coupled with VLS + bougieUse of bougie associated with increased viral spread; need for protection during intubation
      Lang and colleagues
      • Lang A.
      • Shamw K.
      • Lozano R.
      • Wang J.
      Effectiveness of a negative-pressure patient isolation hood shown using particle count.
      CorrespondenceParticles (>0.3 μm) count with and without negative-pressure systemNegative-pressure isolation hood (plastic cover + supports + smoke evacuator)One single measurementExperiment descriptionApplication of negative-pressure generation within barrier-enclosure systemReduction of 98% of particles: 183 vs 5 min without and with negative pressure, respectively
      Jain
      • Jain U.
      Caution regarding enclosures for airway procedures.
      CorrespondenceCommentaryAdjustable frame and CPS + suction systemN/AN/AConstruction of modified enclosure barrierMissing FDA approval for all models; idea of new adjustable barrier-enclosure system (not described)
      Kearsley
      • Kearsley R.
      Intubation boxes for managing the airway in patients with COVID-19.
      CorrespondenceCommentaryPlastic ABN/AN/APlastic AB for airway managementCriticism for missing limitation of aerosols, patient's fitting, intubation success rate, risk of PPE disruption, and complexity
      Gould and colleagues
      • Gould C.L.
      • Alexander P.D.G.
      • Allen C.N.
      • McGrath B.A.
      • Shelton C.L.
      Protecting staff and patients during airway management in the COVID-19 pandemic: are intubation boxes safe?.
      Correspondence in response to research letterSimulation studyABN/ASimulation (?)Application of ABTest of AB in simulation setting increased the difficulty of tracheal intubation, especially during transition between airway devices and when using intubation adjuncts, such as the gum elastic bougie.
      Sorbello and colleagues
      • Sorbello M.
      • Di Giacinto I.
      • Falcetta S.
      • Greif R.
      Ventilation and airway management during cardiopulmonary resuscitation in COVID-19 era.
      Correspondence in response to research letterCommentaryCPSN/ACPS over supraglottic airways during CPRCriticism for difficult manipulation, unfeasible position tests, SAD-aided intubation, delay in CPR, and risk of fire
      Endersby and colleagues
      • Endersby R.V.W.
      • Ho E.C.Y.
      • Spencer A.O.
      • Goldstein D.H.
      • Schubert E.
      Barrier devices for reducing aerosol and droplet transmission in COVID-19 patients.
      Correspondence in response to research lettersSimulation studySurgical Mayo stand + C-arm plastic drapeN/AMannequin (?)Detection of Glo Germ fluorescent dye atomised by laryngotracheal mucosal atomisation device to simulate the production of fine droplets and aerosolWithout barrier, Glo Germ identified on the laryngoscopist's hands, arms, gown, neck, face, eye protection, mask, and extended spread around the OT
      Laosuwan and colleagues
      • Laosuwan P.
      • Earsakul A.
      • Pannangpetch P.
      • Sereeyotin J.
      Acrylic box versus plastic sheet covering on droplet dispersal during extubation in COVID-19 patients.
      CorrespondenceSimulation studyAB (3 configurations); CPSFive simulations for each configuration (AB1, AB2, AB3, CPS, and no barrier) in simulated extubationSelf-designed droplet-generating device with fluorescent dye used to compare three AB configurations (number of stained 5×5 squares outside the boxes: around the mannequin, on the chest of the mannequin, and on the anaesthetist's gown and face shieldOverall droplet dispersion: acrylic AB models (3.3–19.0%), CPS (2.8%), and non-coverage technique (26.3%); all AB showed no contamination on anaesthesia personnel; CPS caused contamination both on the chest and abdomen of anaesthetist (self-contamination)
      Brown and colleagues
      • Brown S.
      • Patrao F.
      • Verma S.
      • Lean A.
      • Flack S.
      • Polaner D.
      Barrier system for airway management of COVID-19 patients.
      Letter to the editorClinical reportCPD on bag barrier systemN/AMannequin and patientsApplication of CPD on bag barrier system for airway managementEconomic and intubation feasible, including assistant's help; proposed removal of the clear drape during mid-laryngoscopy in case of difficulty
      Leyva Moraga and colleagues
      • Leyva Moraga F.A.
      • Leyva Moraga E.
      • Leyva Moraga F.
      • et al.
      Aerosol box, an operating room security measure in COVID-19 pandemic.
      Letter to the editorClinical reportABFive patientsN/AApplication of AB for intubation/extubationAB has proved to be a valuable resource functioning as an adaptive tool to aid in resource-limiting setting. The AB did not represent an obstacle to established protocol, acting as feasible solution in low- and middle-income healthcare settings.
      Yang and colleagues
      • Yang Y.L.
      • Huang C.H.
      • Luk H.N.
      • Tsai P.B.
      Adaptation to the plastic barrier sheet to facilitate intubation during the COVID-19 pandemic.
      Letter to the editorTechnical reportCPS with incisions and tape reinforceN/AMannequin?Use of modified CPS for intubation and extubation (left in place)Modification aimed to improve laryngoscopic manoeuvring; multi-layer option
      Babazade and colleagues
      • Babazade R.
      • Khan E.S.
      • Ibrahim M.
      • Simon M.
      • Vadhera R.B.
      Additional barrier to protect healthcare workers during intubation.
      Letter to the editorTechnical reportCPS with cross-cutN/AMannequin?Use of modified CPS for airway managementEconomic; intubation feasible
      Rehm and colleagues
      • Rehm M.
      • Eichler J.
      • Meidert A.S.
      • Briegel J.
      Protecting health-care workers: use of a body covering transparent sheet during and after intubation of patients with Covid-19.
      Letter to the editorClinical reportFull-body CPSN/A (60 patients?)Mannequin and patientsUse of total-body CPS for airway managementEconomic; intubation feasible; also for transport
      Scapigliati and colleagues
      • Scapigliati A.
      • Gulli A.
      • Semeraro F.
      • et al.
      How to ventilate during CPR in time of Covid-19?.
      Letter to the editorTechnical reportCPSN/ACPS over SAD during CPR in mannequin modelHypothesis of aerosol limitation when using SAD during CPR; measurement of differential inspiration/expiration with spirometer during simulated mechanical ventilationHypothesis of efficacy
      Patino Montoya and Chitilian
      • Patino Montoya M.
      • Chitilian H.V.
      Extubation barrier drape to minimise droplet spread.
      Letter to the editorTechnical reportCPS with midline slitN/ACPS sealed to tracheal tube to prevent aerosolisation and droplets during extubationUse of CPS for extubationThe CPS blocks the dispersion of aerosolised particles during extubation.
      Rosenblatt and Sherman
      • Rosenblatt W.H.
      • Sherman J.D.
      More on barrier enclosure during endotracheal intubation.
      Letter to the editorCommentaryABN/AN/AN/ARestrictions in movement and limitations in emergency; heavy for carrying/moving; issues with cleaning
      Fang and colleagues
      • Fang P.H.
      • Lin Y.Y.
      • Lin C.H.
      A protection tent for airway management in patients with COVID-19 infection.
      Letter to the editorTechnical reportFrame and CPSN/APatients?Construction of enclosure barrierEconomic, flexible, and lightweight
      Swart and Strydom
      • Swart R.
      • Strydom C.
      The qualitative evaluation of the limitation of aerosol spread by a transparent intubation box.
      Letter to the editorSimulation studyPlastic AB + CPS + suction tubeOne experiment in four stepsOptical evaluation of smoke spreadingHome-made smoke source to explore AB retaining capacityAB effectively limits aerosol spread qualitatively, but even adding suction and CPS covering AB does not prevent the escape of aerosol, especially when the internal volume is accessed through arm holes.
      Brown and colleagues
      • Brown H.
      • Preston D.
      • Bhoja R.
      Thinking outside the box: a low-cost and pragmatic alternative to aerosol boxes for endotracheal intubation of COVID-19 patients.
      Letter to the editorSimulation studyCPS over Mayo table frameTwo experiments, comparing with ABAtomised droplet model using fluorescent dye and qualitative assessmentCPS over Mayo frame compared with traditional ABLess spread using CPS over Mayo frame than with traditional AB
      Hung and colleagues
      • Hung O.
      • Hung D.
      • Hung C.
      • Stewart R.
      A simple negative-pressure protective barrier for extubation of COVID-19 patients.
      Research letterSimulation studyCPS tent + suction system appliedN/ACPS tent + suction applied for simulated extubation on mannequinBarrier-enclosure system for extubationSolution to limit the small droplet diffusion out of conventional AB; used successfully in simulation and clinical experience
      Suresh
      • Suresh V.
      Simple innovations in the operating room amid the COVID-19 pandemic.
      Letter to the editorTechnical reportAcrylic AP/CPS tentN/AN/ABarrier-enclosure systems for airway management: AB, CPS tent, and C-ARM cover for anaesthesiologistSuggested use of ‘home-made’ PPE for preserving available resources during the pandemic
      Puthenveettil and Vijayaraghavan
      • Puthenveettil N.
      • Vijayaraghavan S.
      Aerosol box for protection during airway manipulation in covid-19 patients.
      Letter to the editorTechnical reportAcrylic AB (asymmetric ports)N/AN/AAB for airway management (including nasotracheal intubation and LMA placement)AB is ergonomic because of asymmetric ports; not advised for difficult intubation. Authors recommend this device be used for all patients so that the learning curve can be reached before intubation has to perform actual critical COVID patients.
      Asokan and colleagues
      • Asokan K.
      • Babu B.
      • Jayadevan A.
      Barrier enclosure for airway management in COVID-19 pandemic.
      Letter to the editorTechnical reportAcrylic AB (C-shaped curved side panels) with or without CPSN/ADescription and experience in 50+ patients (no information provided)AB for airway management, including obeseThe C-shaped curved side panels are ergonomic for assistant use in obese; proved safe and effective
      Singh and colleagues
      • Singh B.
      • Singla S.
      • Gulia P.
      • Kumar A.
      • Bhanwala R.
      Aerosol containment device for use on suspected COVID-19 patients.
      Letter to the editorTechnical reportCPS + frame with linear cutsN/AN/ACPS + frame for airway managementAdaptable and lightweight; suggested cleaning before removal with alcohol-based disinfectant spray be done in the chamber with the patient breathing spontaneously through face mask and eyes closed
      Raimann and colleagues
      • Raimann F.
      • Kloka J.
      • Martin C.
      • Gilla P.
      • Lotz G.
      • Zacharowski K.
      Visualized effect of the Frankfurt COVid aErosol pRotEction dome—COVERED.
      Letter to the editorSimulation studyModified packaging tray used for heart–lung machine sets (cut/glued/polished)Two experiments (with/without barrier)Simulated cough in mannequin with a mucosal atomisation device filled with a fluorescent dyeInspective evaluation of fluorescent dyeEffective and protective; limits spread of large droplets
      Martin and colleagues
      • Martin C.
      • Kloka J.
      • Lotz G.
      • Zacharowski K.
      • Raimann F.J.
      The Frankfurt COVid aErosol pRotEction Dome—COVERED—a consideration for personal protective equipment improvement and technical note.
      Original articleModified packaging tray used for heart–lung machine sets (cut/glued/polished)N/AN/AModified medical packaging (COVid aErosol pRotEction Dome—‘COVERED’)Economic; recycled material; help possible; need for training, limitations for other manoeuvres, advanced airway techniques, obese patients; intended as extra barrier to be added, and not to replace PPE
      Francom and colleagues
      • Francom C.R.
      • Javia L.R.
      • Wolter N.E.
      • et al.
      Pediatric laryngoscopy and bronchoscopy during the COVID-19 pandemic: a four-center collaborative protocol to improve safety with perioperative management strategies and creation of a surgical tent with disposable drapes.
      Original articleMulticentre protocol descriptionComplete CPS tent (bed/body/suspension over head and chin) + frames + smoke evacuatorN/ASimulations and paediatric patients seriesDescription of surgical procedures (suspected airway foreign body, microlaryngoscopy, and flexible/rigid bronchoscopy) in paediatric patients with tent in placeThe tents are sound to decrease aerosolisation and droplet contamination; little to no added risk to the patient, as the drapes may be rapidly removed; greatly perceived benefit to the safety of the anaesthesiologist, surgeon, and OT staff involved; tent does not replace the need for individual PPE; it can be used when PPE is scarce and preoperative testing is unavailable.
      Foster and colleagues
      • Foster P.
      • Cheung T.
      • Craft P.
      • et al.
      Novel approach to reduce transmission of COVID-19 during tracheostomy.
      Original articleCase reportCombination of CPD, magnetic mat, surgical retractor, and smoke evacuatorOne patientTechnical description + clinical reportUse of combination of CPD, magnetic mat, surgical retractor, and smoke evacuator for performance of tracheostomyEffective and allows safe performance of tracheostomy
      Pollaers and colleagues
      • Pollaers K.
      • Herbert H.
      • Vijayasekaran S.
      Pediatric microlaryngoscopy and bronchoscopy in the COVID-19 era.
      Original articleCase series‘Suspension box’ (polymethyl methacrylate [Perspex] box with three open sides + CPS)Eight paediatric patientsCase series in operatory roomDescription of a modified technique for paediatric microlaryngoscopy and bronchoscopySuspension box, PPE, and team arrangement are theoretically associated with reduced risk
      Chow and colleagues
      • Chow V.L.Y.
      • Chan J.Y.W.
      • Ho V.W.Y.
      • et al.
      Tracheostomy during COVID-19 pandemic—novel approach.
      Original articleCase seriesCPS + horizontal anaesthetic screens (tent)Five patientsDroplets count on 7×7 cm grids on plastic sheet and face shieldsAdoption of plastic tent to contain droplet spreading during tracheostomyDroplet count contamination was mainly over the central upper half of plastic sheet correspondingly to lower neck. Total droplet count was highest along the centre and decreased towards the periphery on both sides. Plastic tent could obviate the need for a face shield given adequate eye protection and respirator.
      Begley and colleagues
      • Begley J.L.
      • Lavery K.E.
      • Nickson C.P.
      • Brewster D.J.
      The aerosol box for intubation in coronavirus disease 2019 patients: an in-situ simulation crossover study.
      Original articleComparison of no AB with two AB in simulation crossover studyAB (two models)36 (12 PPE donned anaesthesiologists/three intubations each): no AB/AB1/AB2Intubation of simulated Cormack–Lehane 2 in mannequin with VLS + bougieApplication of two different AB during intubationPrimary outcome: intubation time longer with both AB (17% <60 s vs 100% <60 s without AB); secondary outcomes: first-pass intubation success: lower (75% and 83%) with AB vs no AB (100%); breaks in preoxygenation mask seal: no differences; breaches or damage to PPE: eight in AB; none without AB; qualitative comments on their experience: discomfort (50%) and increased cognitive load (33%) with AB
      Convissar and colleagues
      • Convissar D.
      • Chang C.Y.
      • Choi W.E.
      • Chang M.G.
      • Bittner E.A.
      The Vacuum Assisted Negative Pressure Isolation Hood (VANISH) system: novel application of the Stryker Neptune suction machine to create COVID-19 negative pressure isolation environments.
      Original articleTechnical descriptionCPS + frame + suction systemN/AN/ACPS over PVC frame connected to Stryker suction system to create negative-pressure environmentAddition of negative-pressure system may clear aerosols and reduce contamination of room. Actual efficacy is not assessed in this report.
      Hill and colleagues
      • Hill E.
      • Crockett C.
      • Circh R.W.
      • Lansville F.
      • Stahel P.F.
      Introducing the “Corona Curtain”: an innovative technique to prevent airborne COVID-19 exposure during emergent intubations.
      Original articleTechnical descriptionCPS over customised framePreliminary use in 25 patientsNo patient information given; 25 cases in emergency department‘Corona Curtain’ barrierUse described as simple, pragmatic, and cost effective
      Alves Filho and colleagues
      • Filho W.A.
      • Teles T.
      • da Fonseca M.R.S.
      • et al.
      Barrier device prototype for open tracheotomy during COVID-19 pandemic.
      Original articleTechnical descriptionCPS + frameN/AN/APolyethylene sheet on metallic frame used for tracheostomy (sterile)Fully autoclavable; free movement inside; incomplete barrier; concerns for correct removal
      Gore and colleagues
      • Gore R.K.
      • Saldana C.
      • Wright D.W.
      • Klein A.M.
      Intubation containment system for improved protection from aerosolized particles during airway management.
      Original articleSimulation studyAcrylic panels + CPSFour mannequin simulationsIntubation using four methods (including control) using a mannequin model with smoke generatorAcrylic panels supplemented by CPS in simulation study with mannequinReduced aerosol dispersion with acrylic panels combined with CPS than with panels or no barrier
      Kinjo and colleagues
      • Kinjo S.
      • Dudley M.
      • Sakai N.
      Modified wake forest type protective shield for an asymptomatic, COVID-19 non-confirmed patient for intubation undergoing urgent surgery.
      Research letterClinical reportMetal brackets + acrylic panelOne patientIntubation/extubation with barrier enclosure of COVID suspected patientApplication of novel barrier-enclosure systemMore economic and easy access than AB; care for metal parts contact
      Dalli and colleagues
      • Dalli J.
      • Khan M.F.
      • Marsh B.
      • Nolan K.
      • Cahill R.A.
      Evaluating intubation boxes for airway management.
      Research letterSimulation studyABOneSimulated OT setting with coughing human volunteer, detection of airflows (assumption that airflows carry droplets/aerosols); schlieren imaging of airflows around the AB during both normal and deep exhalation and during coughing to assess aerosol spreadingHigh-speed imaging to assess airflows inside/outside the ABAB does not contain airflows; visualised airflows also from side ports; concerns for added complexity and secondary aerosolisation during doffing/cleaning
      Matava and colleagues
      • Matava C.T.
      • Kovatsis P.G.
      • Lee J.K.
      • et al.
      Pediatric airway management in COVID-19 patients: consensus guidelines from the society for pediatric anesthesia’s pediatric difficult intubation collaborative and the Canadian pediatric anesthesia society.
      GuidelinesGuidelines for paediatric airway management in COVID-19 patientsCPSN/A (paediatric)N/ADiscussion of barrier systems on anaesthetic equipment and on patient's airway devicesThe PeDI-C recommended a transparent barrier over the airway device and patient's head to trap any aerosolised virus.
      Chahar and colleagues
      • Chahar P.
      • Dugar S.
      • Marciniak D.
      Airway management considerations in patients with COVID-19.
      Short recommendations (curbside consultation)Airway management considerations in COVID-19 patientsAero-Guard barrier device (patent pending, tab and pins collapsible design)N/ATechnical features not providedBarrier-enclosure system for intubationUse of barrier devices, such as screens and intubation boxes should be considered to prevent cross infection during intubation. CPS can be used if a screen and intubation box are not available.
      Sampson and Beckett
      • Sampson C.S.
      • Beckett A.
      Novel, inexpensive portable respiratory protection unit (PRPU) for healthcare workers.
      Case reportIntubation with barrier-enclosure reportPlastic wrap + PVC supportOneN/ABarrier-enclosure system for intubationIntubation feasible
      Bertroche and colleagues
      • Bertroche J.T.
      • Pipkorn P.
      • Zolkind P.
      • Buchman C.A.
      • Zevallos J.P.
      Negative-pressure aerosol cover for COVID-19 tracheostomy.
      Quality improvement studyClinical reportLaryngoscope suspension arm at the head of the bed and tented drape with C-arm plastic cover + smoke evacuatorOneUse of a novel negative-pressure aerosol reduction cover for tracheostomyApplication of barrier enclosure for tracheostomyAllows for generally good mobility of the surgeon's hands and assistant's help; however, limitation in forearm movement; some degree of glare if cover became overlapped
      SickKids The Hospital for Sick Children/University of Toronto
      Website reportDescriptiveCPS + frame (protective tent for ENT surgical paediatric procedures)N/AN/AInstallation of the enclosure barrierDescription of installation and preparation
      Lai
      • Lai H.
      Aerosol box.
      Website reportDescriptiveABN/AN/AConstruction of ABAB minimises large droplet diffusion
      BBC News Services
      BBC News Services
      Coronavirus: NI firm helps develop shield for healthcare staff.
      Website reportDescriptiveABN/AN/ADescription of ABAB minimises large droplet diffusion
      Tso
      • Tso M.
      Coronavirus: Kiwi doctor invents extractor system to protect healthworkers from Covid-19.
      Website reportDescriptiveVacuum systemN/AN/ADescription of extractorExtractor minimises droplet diffusion
      CONMED
      CONMED
      Demonstration of simulated pediatric patient with plastic tent and smoke extractor.
      YouTube videoDescriptiveSmoke extractorN/AN/ASimulation of tent + smoke extractor in paediatric patientThe enclosure system isolates aerosols and the smoke extractor quickly removes them.
      Chan
      • Chan A.
      Should we use an “aerosol box” for intubation?.
      Website reportDescriptiveABN/AN/APros and consAdvantages and disadvantages

      Narrative summary of evidence identified

       Characteristics of studies

      We found a considerable number of relevant reports and studies. Because of the high heterogeneity, small sample sizes, and limited patient data, we elected to write a scoping review resulting in a narrative summary.
      This review included 52 written reports and six websites (Table 1). All were published between December 1, 2019 and May 27, 2020. There were 19 correspondences,
      • Canelli R.
      • Connor C.W.
      • Gonzalez M.
      • Nozari A.
      • Ortega R.
      Barrier enclosure during endotracheal intubation.
      • Cubillos J.
      • Querney J.
      • Rankin A.
      • Moore J.
      • Armstrong K.
      A multipurpose portable negative air flow isolation chamber for aerosol-generating procedures during the COVID-19 pandemic.
      • Fonseca E.O.
      • Blanco H.
      • Alvernia J.E.
      New design for aerosol protection during endotracheal intubation in the coronavirus disease 2019 (COVID-19) pandemic era: the “Anti-Aerosol Igloo” (AAI).
      • Rahmoune F.C.
      • Ben Yahia M.M.
      • Hajjej R.
      • Pic S.
      • Chatti K.
      Protective device during airway management in patients with coronavirus disease 2019 (COVID-19).
      • Lai Y.Y.
      • Chang C.M.
      A carton-made protective shield for suspicious/confirmed COVID-19 intubation and extubation during surgery.
      • Au Yong PS.
      • Chen X.
      Reducing droplet spread during airway manipulation: lessons from the COVID-19 pandemic in Singapore.
      • Lim W.Y.
      • Wong P.
      • Ong S.G.K.
      Reducing droplet spread during airway manipulation. Reply to Au Yong and colleagues (Br J Anaesth 2020; 125: e176–e178).
      • Yang S.S.
      • Zhang M.
      • Chong J.J.R.
      Comparison of three tracheal intubation methods for reducing droplet spread for use in COVID-19 patients.
      • Matava C.T.
      • Yu J.
      • Denning S.
      Clear plastic drapes may be effective at limiting aerosolization and droplet spray during extubation: implications for COVID-19.
      • Malik J.S.
      • Jenner C.
      • Ward P.A.
      Maximising application of the aerosol box in protecting healthcare workers during the COVID-19 pandemic.
      • Cordier P.Y.
      • De La Villeon B.
      • Martin E.
      • Goudard Y.
      • Haen P.
      Health workers’ safety during tracheostomy in COVID-19 patients: homemade protective screen.
      • Zeidan A.
      • Bamadhaj M.
      • Al-Faraidy M.
      • Ali M.
      Videolaryngoscopy intubation in patients with COVID-19: how to minimize risk of aerosolization?.
      • Lang A.
      • Shamw K.
      • Lozano R.
      • Wang J.
      Effectiveness of a negative-pressure patient isolation hood shown using particle count.
      • Jain U.
      Caution regarding enclosures for airway procedures.
      • Kearsley R.
      Intubation boxes for managing the airway in patients with COVID-19.
      • Gould C.L.
      • Alexander P.D.G.
      • Allen C.N.
      • McGrath B.A.
      • Shelton C.L.
      Protecting staff and patients during airway management in the COVID-19 pandemic: are intubation boxes safe?.
      • Sorbello M.
      • Di Giacinto I.
      • Falcetta S.
      • Greif R.
      Ventilation and airway management during cardiopulmonary resuscitation in COVID-19 era.
      • Endersby R.V.W.
      • Ho E.C.Y.
      • Spencer A.O.
      • Goldstein D.H.
      • Schubert E.
      Barrier devices for reducing aerosol and droplet transmission in COVID-19 patients.
      • Laosuwan P.
      • Earsakul A.
      • Pannangpetch P.
      • Sereeyotin J.
      Acrylic box versus plastic sheet covering on droplet dispersal during extubation in COVID-19 patients.
      16 letters to the editor,
      • Brown S.
      • Patrao F.
      • Verma S.
      • Lean A.
      • Flack S.
      • Polaner D.
      Barrier system for airway management of COVID-19 patients.
      • Leyva Moraga F.A.
      • Leyva Moraga E.
      • Leyva Moraga F.
      • et al.
      Aerosol box, an operating room security measure in COVID-19 pandemic.
      • Yang Y.L.
      • Huang C.H.
      • Luk H.N.
      • Tsai P.B.
      Adaptation to the plastic barrier sheet to facilitate intubation during the COVID-19 pandemic.
      • Babazade R.
      • Khan E.S.
      • Ibrahim M.
      • Simon M.
      • Vadhera R.B.
      Additional barrier to protect healthcare workers during intubation.
      • Rehm M.
      • Eichler J.
      • Meidert A.S.
      • Briegel J.
      Protecting health-care workers: use of a body covering transparent sheet during and after intubation of patients with Covid-19.
      • Scapigliati A.
      • Gulli A.
      • Semeraro F.
      • et al.
      How to ventilate during CPR in time of Covid-19?.
      • Patino Montoya M.
      • Chitilian H.V.
      Extubation barrier drape to minimise droplet spread.
      • Rosenblatt W.H.
      • Sherman J.D.
      More on barrier enclosure during endotracheal intubation.
      • Fang P.H.
      • Lin Y.Y.
      • Lin C.H.
      A protection tent for airway management in patients with COVID-19 infection.
      • Swart R.
      • Strydom C.
      The qualitative evaluation of the limitation of aerosol spread by a transparent intubation box.
      • Brown H.
      • Preston D.
      • Bhoja R.
      Thinking outside the box: a low-cost and pragmatic alternative to aerosol boxes for endotracheal intubation of COVID-19 patients.
      ,
      • Suresh V.
      Simple innovations in the operating room amid the COVID-19 pandemic.
      • Puthenveettil N.
      • Vijayaraghavan S.
      Aerosol box for protection during airway manipulation in covid-19 patients.
      • Asokan K.
      • Babu B.
      • Jayadevan A.
      Barrier enclosure for airway management in COVID-19 pandemic.
      • Singh B.
      • Singla S.
      • Gulia P.
      • Kumar A.
      • Bhanwala R.
      Aerosol containment device for use on suspected COVID-19 patients.
      • Raimann F.
      • Kloka J.
      • Martin C.
      • Gilla P.
      • Lotz G.
      • Zacharowski K.
      Visualized effect of the Frankfurt COVid aErosol pRotEction dome—COVERED.
      10 original articles,
      • Martin C.
      • Kloka J.
      • Lotz G.
      • Zacharowski K.
      • Raimann F.J.
      The Frankfurt COVid aErosol pRotEction Dome—COVERED—a consideration for personal protective equipment improvement and technical note.
      • Francom C.R.
      • Javia L.R.
      • Wolter N.E.
      • et al.
      Pediatric laryngoscopy and bronchoscopy during the COVID-19 pandemic: a four-center collaborative protocol to improve safety with perioperative management strategies and creation of a surgical tent with disposable drapes.
      • Foster P.
      • Cheung T.
      • Craft P.
      • et al.
      Novel approach to reduce transmission of COVID-19 during tracheostomy.
      • Pollaers K.
      • Herbert H.
      • Vijayasekaran S.
      Pediatric microlaryngoscopy and bronchoscopy in the COVID-19 era.
      • Chow V.L.Y.
      • Chan J.Y.W.
      • Ho V.W.Y.
      • et al.
      Tracheostomy during COVID-19 pandemic—novel approach.
      • Begley J.L.
      • Lavery K.E.
      • Nickson C.P.
      • Brewster D.J.
      The aerosol box for intubation in coronavirus disease 2019 patients: an in-situ simulation crossover study.
      • Convissar D.
      • Chang C.Y.
      • Choi W.E.
      • Chang M.G.
      • Bittner E.A.
      The Vacuum Assisted Negative Pressure Isolation Hood (VANISH) system: novel application of the Stryker Neptune suction machine to create COVID-19 negative pressure isolation environments.
      • Hill E.
      • Crockett C.
      • Circh R.W.
      • Lansville F.
      • Stahel P.F.
      Introducing the “Corona Curtain”: an innovative technique to prevent airborne COVID-19 exposure during emergent intubations.
      • Filho W.A.
      • Teles T.
      • da Fonseca M.R.S.
      • et al.
      Barrier device prototype for open tracheotomy during COVID-19 pandemic.
      • Gore R.K.
      • Saldana C.
      • Wright D.W.
      • Klein A.M.
      Intubation containment system for improved protection from aerosolized particles during airway management.
      three research letters,
      • Hung O.
      • Hung D.
      • Hung C.
      • Stewart R.
      A simple negative-pressure protective barrier for extubation of COVID-19 patients.
      ,
      • Kinjo S.
      • Dudley M.
      • Sakai N.
      Modified wake forest type protective shield for an asymptomatic, COVID-19 non-confirmed patient for intubation undergoing urgent surgery.
      ,
      • Dalli J.
      • Khan M.F.
      • Marsh B.
      • Nolan K.
      • Cahill R.A.
      Evaluating intubation boxes for airway management.
      one guideline,
      • Matava C.T.
      • Kovatsis P.G.
      • Lee J.K.
      • et al.
      Pediatric airway management in COVID-19 patients: consensus guidelines from the society for pediatric anesthesia’s pediatric difficult intubation collaborative and the Canadian pediatric anesthesia society.
      one short recommendation,
      • Chahar P.
      • Dugar S.
      • Marciniak D.
      Airway management considerations in patients with COVID-19.
      one case report,
      • Sampson C.S.
      • Beckett A.
      Novel, inexpensive portable respiratory protection unit (PRPU) for healthcare workers.
      and one quality improvement study.
      • Bertroche J.T.
      • Pipkorn P.
      • Zolkind P.
      • Buchman C.A.
      • Zevallos J.P.
      Negative-pressure aerosol cover for COVID-19 tracheostomy.
      Of these reports, there were only six case reports or small case series.
      • Fonseca E.O.
      • Blanco H.
      • Alvernia J.E.
      New design for aerosol protection during endotracheal intubation in the coronavirus disease 2019 (COVID-19) pandemic era: the “Anti-Aerosol Igloo” (AAI).
      ,
      • Zeidan A.
      • Bamadhaj M.
      • Al-Faraidy M.
      • Ali M.
      Videolaryngoscopy intubation in patients with COVID-19: how to minimize risk of aerosolization?.
      ,
      • Foster P.
      • Cheung T.
      • Craft P.
      • et al.
      Novel approach to reduce transmission of COVID-19 during tracheostomy.
      • Pollaers K.
      • Herbert H.
      • Vijayasekaran S.
      Pediatric microlaryngoscopy and bronchoscopy in the COVID-19 era.
      • Chow V.L.Y.
      • Chan J.Y.W.
      • Ho V.W.Y.
      • et al.
      Tracheostomy during COVID-19 pandemic—novel approach.
      ,
      • Sampson C.S.
      • Beckett A.
      Novel, inexpensive portable respiratory protection unit (PRPU) for healthcare workers.
      The most common barrier-enclosure types were plastic wraps or tents (25 reports),
      • Cubillos J.
      • Querney J.
      • Rankin A.
      • Moore J.
      • Armstrong K.
      A multipurpose portable negative air flow isolation chamber for aerosol-generating procedures during the COVID-19 pandemic.
      ,
      • Au Yong PS.
      • Chen X.
      Reducing droplet spread during airway manipulation: lessons from the COVID-19 pandemic in Singapore.
      ,
      • Matava C.T.
      • Yu J.
      • Denning S.
      Clear plastic drapes may be effective at limiting aerosolization and droplet spray during extubation: implications for COVID-19.
      ,
      • Zeidan A.
      • Bamadhaj M.
      • Al-Faraidy M.
      • Ali M.
      Videolaryngoscopy intubation in patients with COVID-19: how to minimize risk of aerosolization?.
      ,
      • Jain U.
      Caution regarding enclosures for airway procedures.
      ,
      • Brown S.
      • Patrao F.
      • Verma S.
      • Lean A.
      • Flack S.
      • Polaner D.
      Barrier system for airway management of COVID-19 patients.
      • Leyva Moraga F.A.
      • Leyva Moraga E.
      • Leyva Moraga F.
      • et al.
      Aerosol box, an operating room security measure in COVID-19 pandemic.
      • Yang Y.L.
      • Huang C.H.
      • Luk H.N.
      • Tsai P.B.
      Adaptation to the plastic barrier sheet to facilitate intubation during the COVID-19 pandemic.
      • Babazade R.
      • Khan E.S.
      • Ibrahim M.
      • Simon M.
      • Vadhera R.B.
      Additional barrier to protect healthcare workers during intubation.
      • Rehm M.
      • Eichler J.
      • Meidert A.S.
      • Briegel J.
      Protecting health-care workers: use of a body covering transparent sheet during and after intubation of patients with Covid-19.
      • Scapigliati A.
      • Gulli A.
      • Semeraro F.
      • et al.
      How to ventilate during CPR in time of Covid-19?.
      • Patino Montoya M.
      • Chitilian H.V.
      Extubation barrier drape to minimise droplet spread.
      ,
      • Fang P.H.
      • Lin Y.Y.
      • Lin C.H.
      A protection tent for airway management in patients with COVID-19 infection.
      ,
      • Brown H.
      • Preston D.
      • Bhoja R.
      Thinking outside the box: a low-cost and pragmatic alternative to aerosol boxes for endotracheal intubation of COVID-19 patients.
      ,
      • Hung O.
      • Hung D.
      • Hung C.
      • Stewart R.
      A simple negative-pressure protective barrier for extubation of COVID-19 patients.
      ,
      • Singh B.
      • Singla S.
      • Gulia P.
      • Kumar A.
      • Bhanwala R.
      Aerosol containment device for use on suspected COVID-19 patients.
      ,
      • Raimann F.
      • Kloka J.
      • Martin C.
      • Gilla P.
      • Lotz G.
      • Zacharowski K.
      Visualized effect of the Frankfurt COVid aErosol pRotEction dome—COVERED.
      ,
      • Francom C.R.
      • Javia L.R.
      • Wolter N.E.
      • et al.
      Pediatric laryngoscopy and bronchoscopy during the COVID-19 pandemic: a four-center collaborative protocol to improve safety with perioperative management strategies and creation of a surgical tent with disposable drapes.
      ,
      • Foster P.
      • Cheung T.
      • Craft P.
      • et al.
      Novel approach to reduce transmission of COVID-19 during tracheostomy.
      ,
      • Chow V.L.Y.
      • Chan J.Y.W.
      • Ho V.W.Y.
      • et al.
      Tracheostomy during COVID-19 pandemic—novel approach.
      ,
      • Convissar D.
      • Chang C.Y.
      • Choi W.E.
      • Chang M.G.
      • Bittner E.A.
      The Vacuum Assisted Negative Pressure Isolation Hood (VANISH) system: novel application of the Stryker Neptune suction machine to create COVID-19 negative pressure isolation environments.
      ,
      • Hill E.
      • Crockett C.
      • Circh R.W.
      • Lansville F.
      • Stahel P.F.
      Introducing the “Corona Curtain”: an innovative technique to prevent airborne COVID-19 exposure during emergent intubations.
      ,
      • Matava C.T.
      • Kovatsis P.G.
      • Lee J.K.
      • et al.
      Pediatric airway management in COVID-19 patients: consensus guidelines from the society for pediatric anesthesia’s pediatric difficult intubation collaborative and the Canadian pediatric anesthesia society.
      ,
      • Sampson C.S.
      • Beckett A.
      Novel, inexpensive portable respiratory protection unit (PRPU) for healthcare workers.
      ,
      acrylic aerosol boxes (19 reports),
      • Canelli R.
      • Connor C.W.
      • Gonzalez M.
      • Nozari A.
      • Ortega R.
      Barrier enclosure during endotracheal intubation.
      • Cubillos J.
      • Querney J.
      • Rankin A.
      • Moore J.
      • Armstrong K.
      A multipurpose portable negative air flow isolation chamber for aerosol-generating procedures during the COVID-19 pandemic.
      • Fonseca E.O.
      • Blanco H.
      • Alvernia J.E.
      New design for aerosol protection during endotracheal intubation in the coronavirus disease 2019 (COVID-19) pandemic era: the “Anti-Aerosol Igloo” (AAI).
      ,
      • Lai Y.Y.
      • Chang C.M.
      A carton-made protective shield for suspicious/confirmed COVID-19 intubation and extubation during surgery.
      ,
      • Yang S.S.
      • Zhang M.
      • Chong J.J.R.
      Comparison of three tracheal intubation methods for reducing droplet spread for use in COVID-19 patients.
      ,
      • Zeidan A.
      • Bamadhaj M.
      • Al-Faraidy M.
      • Ali M.
      Videolaryngoscopy intubation in patients with COVID-19: how to minimize risk of aerosolization?.
      ,
      • Lang A.
      • Shamw K.
      • Lozano R.
      • Wang J.
      Effectiveness of a negative-pressure patient isolation hood shown using particle count.
      ,
      • Kearsley R.
      Intubation boxes for managing the airway in patients with COVID-19.
      ,
      • Gould C.L.
      • Alexander P.D.G.
      • Allen C.N.
      • McGrath B.A.
      • Shelton C.L.
      Protecting staff and patients during airway management in the COVID-19 pandemic: are intubation boxes safe?.
      ,
      • Laosuwan P.
      • Earsakul A.
      • Pannangpetch P.
      • Sereeyotin J.
      Acrylic box versus plastic sheet covering on droplet dispersal during extubation in COVID-19 patients.
      ,
      • Leyva Moraga F.A.
      • Leyva Moraga E.
      • Leyva Moraga F.
      • et al.
      Aerosol box, an operating room security measure in COVID-19 pandemic.
      ,
      • Suresh V.
      Simple innovations in the operating room amid the COVID-19 pandemic.
      ,
      • Puthenveettil N.
      • Vijayaraghavan S.
      Aerosol box for protection during airway manipulation in covid-19 patients.
      ,
      • Pollaers K.
      • Herbert H.
      • Vijayasekaran S.
      Pediatric microlaryngoscopy and bronchoscopy in the COVID-19 era.
      ,
      • Begley J.L.
      • Lavery K.E.
      • Nickson C.P.
      • Brewster D.J.
      The aerosol box for intubation in coronavirus disease 2019 patients: an in-situ simulation crossover study.
      ,
      • Dalli J.
      • Khan M.F.
      • Marsh B.
      • Nolan K.
      • Cahill R.A.
      Evaluating intubation boxes for airway management.
      ,
      • Chahar P.
      • Dugar S.
      • Marciniak D.
      Airway management considerations in patients with COVID-19.
      ,
      • Lai H.
      Aerosol box.
      ,
      BBC News Services
      Coronavirus: NI firm helps develop shield for healthcare staff.
      and combinations of aerosol boxes and plastic wraps (eight reports).
      • Fonseca E.O.
      • Blanco H.
      • Alvernia J.E.
      New design for aerosol protection during endotracheal intubation in the coronavirus disease 2019 (COVID-19) pandemic era: the “Anti-Aerosol Igloo” (AAI).
      ,
      • Lai Y.Y.
      • Chang C.M.
      A carton-made protective shield for suspicious/confirmed COVID-19 intubation and extubation during surgery.
      ,
      • Malik J.S.
      • Jenner C.
      • Ward P.A.
      Maximising application of the aerosol box in protecting healthcare workers during the COVID-19 pandemic.
      ,
      • Zeidan A.
      • Bamadhaj M.
      • Al-Faraidy M.
      • Ali M.
      Videolaryngoscopy intubation in patients with COVID-19: how to minimize risk of aerosolization?.
      ,
      • Swart R.
      • Strydom C.
      The qualitative evaluation of the limitation of aerosol spread by a transparent intubation box.
      ,
      • Asokan K.
      • Babu B.
      • Jayadevan A.
      Barrier enclosure for airway management in COVID-19 pandemic.
      ,
      • Pollaers K.
      • Herbert H.
      • Vijayasekaran S.
      Pediatric microlaryngoscopy and bronchoscopy in the COVID-19 era.
      ,
      • Gore R.K.
      • Saldana C.
      • Wright D.W.
      • Klein A.M.
      Intubation containment system for improved protection from aerosolized particles during airway management.
      Eleven reports included other types of barrier enclosures (modified incubator hood,
      • Rahmoune F.C.
      • Ben Yahia M.M.
      • Hajjej R.
      • Pic S.
      • Chatti K.
      Protective device during airway management in patients with coronavirus disease 2019 (COVID-19).
      carton box,
      • Lai Y.Y.
      • Chang C.M.
      A carton-made protective shield for suspicious/confirmed COVID-19 intubation and extubation during surgery.
      acrylic panels,
      • Kinjo S.
      • Dudley M.
      • Sakai N.
      Modified wake forest type protective shield for an asymptomatic, COVID-19 non-confirmed patient for intubation undergoing urgent surgery.
      surgical retractors, frames and anaesthetic poles,
      • Endersby R.V.W.
      • Ho E.C.Y.
      • Spencer A.O.
      • Goldstein D.H.
      • Schubert E.
      Barrier devices for reducing aerosol and droplet transmission in COVID-19 patients.
      ,
      • Foster P.
      • Cheung T.
      • Craft P.
      • et al.
      Novel approach to reduce transmission of COVID-19 during tracheostomy.
      ,
      • Chow V.L.Y.
      • Chan J.Y.W.
      • Ho V.W.Y.
      • et al.
      Tracheostomy during COVID-19 pandemic—novel approach.
      ,
      • Filho W.A.
      • Teles T.
      • da Fonseca M.R.S.
      • et al.
      Barrier device prototype for open tracheotomy during COVID-19 pandemic.
      external fixators,
      • Cordier P.Y.
      • De La Villeon B.
      • Martin E.
      • Goudard Y.
      • Haen P.
      Health workers’ safety during tracheostomy in COVID-19 patients: homemade protective screen.
      suspension laryngoscopy support,
      • Francom C.R.
      • Javia L.R.
      • Wolter N.E.
      • et al.
      Pediatric laryngoscopy and bronchoscopy during the COVID-19 pandemic: a four-center collaborative protocol to improve safety with perioperative management strategies and creation of a surgical tent with disposable drapes.
      ,
      • Bertroche J.T.
      • Pipkorn P.
      • Zolkind P.
      • Buchman C.A.
      • Zevallos J.P.
      Negative-pressure aerosol cover for COVID-19 tracheostomy.
      and modified packaging tray
      • Martin C.
      • Kloka J.
      • Lotz G.
      • Zacharowski K.
      • Raimann F.J.
      The Frankfurt COVid aErosol pRotEction Dome—COVERED—a consideration for personal protective equipment improvement and technical note.
      ). In 10 cases, a smoke evacuator/aspirator was reported.
      • Cubillos J.
      • Querney J.
      • Rankin A.
      • Moore J.
      • Armstrong K.
      A multipurpose portable negative air flow isolation chamber for aerosol-generating procedures during the COVID-19 pandemic.
      ,
      • Lang A.
      • Shamw K.
      • Lozano R.
      • Wang J.
      Effectiveness of a negative-pressure patient isolation hood shown using particle count.
      ,
      • Jain U.
      Caution regarding enclosures for airway procedures.
      ,
      • Swart R.
      • Strydom C.
      The qualitative evaluation of the limitation of aerosol spread by a transparent intubation box.
      ,
      • Francom C.R.
      • Javia L.R.
      • Wolter N.E.
      • et al.
      Pediatric laryngoscopy and bronchoscopy during the COVID-19 pandemic: a four-center collaborative protocol to improve safety with perioperative management strategies and creation of a surgical tent with disposable drapes.
      ,
      • Foster P.
      • Cheung T.
      • Craft P.
      • et al.
      Novel approach to reduce transmission of COVID-19 during tracheostomy.
      ,
      • Convissar D.
      • Chang C.Y.
      • Choi W.E.
      • Chang M.G.
      • Bittner E.A.
      The Vacuum Assisted Negative Pressure Isolation Hood (VANISH) system: novel application of the Stryker Neptune suction machine to create COVID-19 negative pressure isolation environments.
      ,
      • Bertroche J.T.
      • Pipkorn P.
      • Zolkind P.
      • Buchman C.A.
      • Zevallos J.P.
      Negative-pressure aerosol cover for COVID-19 tracheostomy.
      ,
      • Tso M.
      Coronavirus: Kiwi doctor invents extractor system to protect healthworkers from Covid-19.
      ,
      CONMED
      Demonstration of simulated pediatric patient with plastic tent and smoke extractor.
      Sample sizes were often not given.
      • Cubillos J.
      • Querney J.
      • Rankin A.
      • Moore J.
      • Armstrong K.
      A multipurpose portable negative air flow isolation chamber for aerosol-generating procedures during the COVID-19 pandemic.
      ,
      • Fonseca E.O.
      • Blanco H.
      • Alvernia J.E.
      New design for aerosol protection during endotracheal intubation in the coronavirus disease 2019 (COVID-19) pandemic era: the “Anti-Aerosol Igloo” (AAI).
      ,
      • Lai Y.Y.
      • Chang C.M.
      A carton-made protective shield for suspicious/confirmed COVID-19 intubation and extubation during surgery.
      • Au Yong PS.
      • Chen X.
      Reducing droplet spread during airway manipulation: lessons from the COVID-19 pandemic in Singapore.
      • Lim W.Y.
      • Wong P.
      • Ong S.G.K.
      Reducing droplet spread during airway manipulation. Reply to Au Yong and colleagues (Br J Anaesth 2020; 125: e176–e178).
      • Yang S.S.
      • Zhang M.
      • Chong J.J.R.
      Comparison of three tracheal intubation methods for reducing droplet spread for use in COVID-19 patients.
      ,
      • Malik J.S.
      • Jenner C.
      • Ward P.A.
      Maximising application of the aerosol box in protecting healthcare workers during the COVID-19 pandemic.
      ,
      • Cordier P.Y.
      • De La Villeon B.
      • Martin E.
      • Goudard Y.
      • Haen P.
      Health workers’ safety during tracheostomy in COVID-19 patients: homemade protective screen.
      ,
      • Jain U.
      Caution regarding enclosures for airway procedures.
      • Kearsley R.
      Intubation boxes for managing the airway in patients with COVID-19.
      • Gould C.L.
      • Alexander P.D.G.
      • Allen C.N.
      • McGrath B.A.
      • Shelton C.L.
      Protecting staff and patients during airway management in the COVID-19 pandemic: are intubation boxes safe?.
      • Sorbello M.
      • Di Giacinto I.
      • Falcetta S.
      • Greif R.
      Ventilation and airway management during cardiopulmonary resuscitation in COVID-19 era.
      • Endersby R.V.W.
      • Ho E.C.Y.
      • Spencer A.O.
      • Goldstein D.H.
      • Schubert E.
      Barrier devices for reducing aerosol and droplet transmission in COVID-19 patients.
      ,
      • Brown S.
      • Patrao F.
      • Verma S.
      • Lean A.
      • Flack S.
      • Polaner D.
      Barrier system for airway management of COVID-19 patients.
      ,
      • Yang Y.L.
      • Huang C.H.
      • Luk H.N.
      • Tsai P.B.
      Adaptation to the plastic barrier sheet to facilitate intubation during the COVID-19 pandemic.
      • Babazade R.
      • Khan E.S.
      • Ibrahim M.
      • Simon M.
      • Vadhera R.B.
      Additional barrier to protect healthcare workers during intubation.
      • Rehm M.
      • Eichler J.
      • Meidert A.S.
      • Briegel J.
      Protecting health-care workers: use of a body covering transparent sheet during and after intubation of patients with Covid-19.
      ,
      • Patino Montoya M.
      • Chitilian H.V.
      Extubation barrier drape to minimise droplet spread.
      • Rosenblatt W.H.
      • Sherman J.D.
      More on barrier enclosure during endotracheal intubation.
      • Fang P.H.
      • Lin Y.Y.
      • Lin C.H.
      A protection tent for airway management in patients with COVID-19 infection.
      ,
      • Brown H.
      • Preston D.
      • Bhoja R.
      Thinking outside the box: a low-cost and pragmatic alternative to aerosol boxes for endotracheal intubation of COVID-19 patients.
      ,
      • Martin C.
      • Kloka J.
      • Lotz G.
      • Zacharowski K.
      • Raimann F.J.
      The Frankfurt COVid aErosol pRotEction Dome—COVERED—a consideration for personal protective equipment improvement and technical note.
      ,
      • Francom C.R.
      • Javia L.R.
      • Wolter N.E.
      • et al.
      Pediatric laryngoscopy and bronchoscopy during the COVID-19 pandemic: a four-center collaborative protocol to improve safety with perioperative management strategies and creation of a surgical tent with disposable drapes.
      ,
      • Convissar D.
      • Chang C.Y.
      • Choi W.E.
      • Chang M.G.
      • Bittner E.A.
      The Vacuum Assisted Negative Pressure Isolation Hood (VANISH) system: novel application of the Stryker Neptune suction machine to create COVID-19 negative pressure isolation environments.
      ,
      • Filho W.A.
      • Teles T.
      • da Fonseca M.R.S.
      • et al.
      Barrier device prototype for open tracheotomy during COVID-19 pandemic.
      ,
      • Matava C.T.
      • Kovatsis P.G.
      • Lee J.K.
      • et al.
      Pediatric airway management in COVID-19 patients: consensus guidelines from the society for pediatric anesthesia’s pediatric difficult intubation collaborative and the Canadian pediatric anesthesia society.
      ,
      • Chahar P.
      • Dugar S.
      • Marciniak D.
      Airway management considerations in patients with COVID-19.
      ,
      • Lai H.
      Aerosol box.
      ,
      BBC News Services
      Coronavirus: NI firm helps develop shield for healthcare staff.
      Cases of barrier-enclosure use with one mannequin or one human were noted in eight reports,
      • Matava C.T.
      • Yu J.
      • Denning S.
      Clear plastic drapes may be effective at limiting aerosolization and droplet spray during extubation: implications for COVID-19.
      ,
      • Zeidan A.
      • Bamadhaj M.
      • Al-Faraidy M.
      • Ali M.
      Videolaryngoscopy intubation in patients with COVID-19: how to minimize risk of aerosolization?.
      ,
      • Lang A.
      • Shamw K.
      • Lozano R.
      • Wang J.
      Effectiveness of a negative-pressure patient isolation hood shown using particle count.
      ,
      • Foster P.
      • Cheung T.
      • Craft P.
      • et al.
      Novel approach to reduce transmission of COVID-19 during tracheostomy.
      ,
      • Kinjo S.
      • Dudley M.
      • Sakai N.
      Modified wake forest type protective shield for an asymptomatic, COVID-19 non-confirmed patient for intubation undergoing urgent surgery.
      ,
      • Sampson C.S.
      • Beckett A.
      Novel, inexpensive portable respiratory protection unit (PRPU) for healthcare workers.
      ,
      • Sorbello M.
      • El-Boghdadly K.
      • Di Giacinto I.
      • et al.
      The Italian coronavirus disease 2019 outbreak: recommendations from clinical practice.
      ,
      • Feldman O.
      • Meir M.
      • Shavit D.
      • Idelman R.
      • Shavit I.
      Exposure to a surrogate measure of contamination from simulated patients by emergency department personnel wearing personal protective equipment.
      five cases in three reports,
      • Laosuwan P.
      • Earsakul A.
      • Pannangpetch P.
      • Sereeyotin J.
      Acrylic box versus plastic sheet covering on droplet dispersal during extubation in COVID-19 patients.
      ,
      • Leyva Moraga F.A.
      • Leyva Moraga E.
      • Leyva Moraga F.
      • et al.
      Aerosol box, an operating room security measure in COVID-19 pandemic.
      ,
      • Chow V.L.Y.
      • Chan J.Y.W.
      • Ho V.W.Y.
      • et al.
      Tracheostomy during COVID-19 pandemic—novel approach.
      and series of 25 or more cases in three reports.
      • Asokan K.
      • Babu B.
      • Jayadevan A.
      Barrier enclosure for airway management in COVID-19 pandemic.
      ,
      • Begley J.L.
      • Lavery K.E.
      • Nickson C.P.
      • Brewster D.J.
      The aerosol box for intubation in coronavirus disease 2019 patients: an in-situ simulation crossover study.
      ,
      • Hill E.
      • Crockett C.
      • Circh R.W.
      • Lansville F.
      • Stahel P.F.
      Introducing the “Corona Curtain”: an innovative technique to prevent airborne COVID-19 exposure during emergent intubations.
      The reported settings were simulations with mannequins in 20 cases,
      • Canelli R.
      • Connor C.W.
      • Gonzalez M.
      • Nozari A.
      • Ortega R.
      Barrier enclosure during endotracheal intubation.
      • Cubillos J.
      • Querney J.
      • Rankin A.
      • Moore J.
      • Armstrong K.
      A multipurpose portable negative air flow isolation chamber for aerosol-generating procedures during the COVID-19 pandemic.
      • Fonseca E.O.
      • Blanco H.
      • Alvernia J.E.
      New design for aerosol protection during endotracheal intubation in the coronavirus disease 2019 (COVID-19) pandemic era: the “Anti-Aerosol Igloo” (AAI).
      ,
      • Yang S.S.
      • Zhang M.
      • Chong J.J.R.
      Comparison of three tracheal intubation methods for reducing droplet spread for use in COVID-19 patients.
      • Matava C.T.
      • Yu J.
      • Denning S.
      Clear plastic drapes may be effective at limiting aerosolization and droplet spray during extubation: implications for COVID-19.
      • Malik J.S.
      • Jenner C.
      • Ward P.A.
      Maximising application of the aerosol box in protecting healthcare workers during the COVID-19 pandemic.
      ,
      • Lang A.
      • Shamw K.
      • Lozano R.
      • Wang J.
      Effectiveness of a negative-pressure patient isolation hood shown using particle count.
      ,
      • Gould C.L.
      • Alexander P.D.G.
      • Allen C.N.
      • McGrath B.A.
      • Shelton C.L.
      Protecting staff and patients during airway management in the COVID-19 pandemic: are intubation boxes safe?.
      ,
      • Endersby R.V.W.
      • Ho E.C.Y.
      • Spencer A.O.
      • Goldstein D.H.
      • Schubert E.
      Barrier devices for reducing aerosol and droplet transmission in COVID-19 patients.
      • Laosuwan P.
      • Earsakul A.
      • Pannangpetch P.
      • Sereeyotin J.
      Acrylic box versus plastic sheet covering on droplet dispersal during extubation in COVID-19 patients.
      • Brown S.
      • Patrao F.
      • Verma S.
      • Lean A.
      • Flack S.
      • Polaner D.
      Barrier system for airway management of COVID-19 patients.
      ,
      • Yang Y.L.
      • Huang C.H.
      • Luk H.N.
      • Tsai P.B.
      Adaptation to the plastic barrier sheet to facilitate intubation during the COVID-19 pandemic.
      • Babazade R.
      • Khan E.S.
      • Ibrahim M.
      • Simon M.
      • Vadhera R.B.
      Additional barrier to protect healthcare workers during intubation.
      • Rehm M.
      • Eichler J.
      • Meidert A.S.
      • Briegel J.
      Protecting health-care workers: use of a body covering transparent sheet during and after intubation of patients with Covid-19.
      • Scapigliati A.
      • Gulli A.
      • Semeraro F.
      • et al.
      How to ventilate during CPR in time of Covid-19?.
      ,
      • Raimann F.
      • Kloka J.
      • Martin C.
      • Gilla P.
      • Lotz G.
      • Zacharowski K.
      Visualized effect of the Frankfurt COVid aErosol pRotEction dome—COVERED.
      ,
      • Francom C.R.
      • Javia L.R.
      • Wolter N.E.
      • et al.
      Pediatric laryngoscopy and bronchoscopy during the COVID-19 pandemic: a four-center collaborative protocol to improve safety with perioperative management strategies and creation of a surgical tent with disposable drapes.
      ,
      • Begley J.L.
      • Lavery K.E.
      • Nickson C.P.
      • Brewster D.J.
      The aerosol box for intubation in coronavirus disease 2019 patients: an in-situ simulation crossover study.
      ,
      • Gore R.K.
      • Saldana C.
      • Wright D.W.
      • Klein A.M.
      Intubation containment system for improved protection from aerosolized particles during airway management.
      ,
      CONMED
      Demonstration of simulated pediatric patient with plastic tent and smoke extractor.
      simulations with study volunteers in two cases,
      • Au Yong PS.
      • Chen X.
      Reducing droplet spread during airway manipulation: lessons from the COVID-19 pandemic in Singapore.
      ,
      • Dalli J.
      • Khan M.F.
      • Marsh B.
      • Nolan K.
      • Cahill R.A.
      Evaluating intubation boxes for airway management.
      use in adult patients in 11 cases,
      • Rahmoune F.C.
      • Ben Yahia M.M.
      • Hajjej R.
      • Pic S.
      • Chatti K.
      Protective device during airway management in patients with coronavirus disease 2019 (COVID-19).
      ,
      • Zeidan A.
      • Bamadhaj M.
      • Al-Faraidy M.
      • Ali M.
      Videolaryngoscopy intubation in patients with COVID-19: how to minimize risk of aerosolization?.
      ,
      • Brown S.
      • Patrao F.
      • Verma S.
      • Lean A.
      • Flack S.
      • Polaner D.
      Barrier system for airway management of COVID-19 patients.
      ,
      • Rehm M.
      • Eichler J.
      • Meidert A.S.
      • Briegel J.
      Protecting health-care workers: use of a body covering transparent sheet during and after intubation of patients with Covid-19.
      ,
      • Fang P.H.
      • Lin Y.Y.
      • Lin C.H.
      A protection tent for airway management in patients with COVID-19 infection.
      ,
      • Asokan K.
      • Babu B.
      • Jayadevan A.
      Barrier enclosure for airway management in COVID-19 pandemic.
      ,
      • Foster P.
      • Cheung T.
      • Craft P.
      • et al.
      Novel approach to reduce transmission of COVID-19 during tracheostomy.
      ,
      • Chow V.L.Y.
      • Chan J.Y.W.
      • Ho V.W.Y.
      • et al.
      Tracheostomy during COVID-19 pandemic—novel approach.
      ,
      • Hill E.
      • Crockett C.
      • Circh R.W.
      • Lansville F.
      • Stahel P.F.
      Introducing the “Corona Curtain”: an innovative technique to prevent airborne COVID-19 exposure during emergent intubations.
      ,
      • Kinjo S.
      • Dudley M.
      • Sakai N.
      Modified wake forest type protective shield for an asymptomatic, COVID-19 non-confirmed patient for intubation undergoing urgent surgery.
      ,
      • Bertroche J.T.
      • Pipkorn P.
      • Zolkind P.
      • Buchman C.A.
      • Zevallos J.P.
      Negative-pressure aerosol cover for COVID-19 tracheostomy.
      and four in paediatric patients.
      • Francom C.R.
      • Javia L.R.
      • Wolter N.E.
      • et al.
      Pediatric laryngoscopy and bronchoscopy during the COVID-19 pandemic: a four-center collaborative protocol to improve safety with perioperative management strategies and creation of a surgical tent with disposable drapes.
      ,
      • Pollaers K.
      • Herbert H.
      • Vijayasekaran S.
      Pediatric microlaryngoscopy and bronchoscopy in the COVID-19 era.
      ,
      • Matava C.T.
      • Kovatsis P.G.
      • Lee J.K.
      • et al.
      Pediatric airway management in COVID-19 patients: consensus guidelines from the society for pediatric anesthesia’s pediatric difficult intubation collaborative and the Canadian pediatric anesthesia society.
      ,
      In 24 reports, there was either no setting described or there was a barrier-enclosure description without demonstration.
      • Fonseca E.O.
      • Blanco H.
      • Alvernia J.E.
      New design for aerosol protection during endotracheal intubation in the coronavirus disease 2019 (COVID-19) pandemic era: the “Anti-Aerosol Igloo” (AAI).
      • Rahmoune F.C.
      • Ben Yahia M.M.
      • Hajjej R.
      • Pic S.
      • Chatti K.
      Protective device during airway management in patients with coronavirus disease 2019 (COVID-19).
      • Lai Y.Y.
      • Chang C.M.
      A carton-made protective shield for suspicious/confirmed COVID-19 intubation and extubation during surgery.
      ,
      • Lim W.Y.
      • Wong P.
      • Ong S.G.K.
      Reducing droplet spread during airway manipulation. Reply to Au Yong and colleagues (Br J Anaesth 2020; 125: e176–e178).
      ,
      • Malik J.S.
      • Jenner C.
      • Ward P.A.
      Maximising application of the aerosol box in protecting healthcare workers during the COVID-19 pandemic.
      ,
      • Cordier P.Y.
      • De La Villeon B.
      • Martin E.
      • Goudard Y.
      • Haen P.
      Health workers’ safety during tracheostomy in COVID-19 patients: homemade protective screen.
      ,
      • Jain U.
      Caution regarding enclosures for airway procedures.
      ,
      • Kearsley R.
      Intubation boxes for managing the airway in patients with COVID-19.
      ,
      • Sorbello M.
      • Di Giacinto I.
      • Falcetta S.
      • Greif R.
      Ventilation and airway management during cardiopulmonary resuscitation in COVID-19 era.
      ,
      • Leyva Moraga F.A.
      • Leyva Moraga E.
      • Leyva Moraga F.
      • et al.
      Aerosol box, an operating room security measure in COVID-19 pandemic.
      • Yang Y.L.
      • Huang C.H.
      • Luk H.N.
      • Tsai P.B.
      Adaptation to the plastic barrier sheet to facilitate intubation during the COVID-19 pandemic.
      • Babazade R.
      • Khan E.S.
      • Ibrahim M.
      • Simon M.
      • Vadhera R.B.
      Additional barrier to protect healthcare workers during intubation.
      ,
      • Patino Montoya M.
      • Chitilian H.V.
      Extubation barrier drape to minimise droplet spread.
      • Rosenblatt W.H.
      • Sherman J.D.
      More on barrier enclosure during endotracheal intubation.
      • Fang P.H.
      • Lin Y.Y.
      • Lin C.H.
      A protection tent for airway management in patients with COVID-19 infection.
      • Swart R.
      • Strydom C.
      The qualitative evaluation of the limitation of aerosol spread by a transparent intubation box.
      ,
      • Hung O.
      • Hung D.
      • Hung C.
      • Stewart R.
      A simple negative-pressure protective barrier for extubation of COVID-19 patients.
      ,
      • Singh B.
      • Singla S.
      • Gulia P.
      • Kumar A.
      • Bhanwala R.
      Aerosol containment device for use on suspected COVID-19 patients.
      ,
      • Martin C.
      • Kloka J.
      • Lotz G.
      • Zacharowski K.
      • Raimann F.J.
      The Frankfurt COVid aErosol pRotEction Dome—COVERED—a consideration for personal protective equipment improvement and technical note.
      ,
      • Convissar D.
      • Chang C.Y.
      • Choi W.E.
      • Chang M.G.
      • Bittner E.A.
      The Vacuum Assisted Negative Pressure Isolation Hood (VANISH) system: novel application of the Stryker Neptune suction machine to create COVID-19 negative pressure isolation environments.
      ,
      • Matava C.T.
      • Kovatsis P.G.
      • Lee J.K.
      • et al.
      Pediatric airway management in COVID-19 patients: consensus guidelines from the society for pediatric anesthesia’s pediatric difficult intubation collaborative and the Canadian pediatric anesthesia society.
      • Chahar P.
      • Dugar S.
      • Marciniak D.
      Airway management considerations in patients with COVID-19.
      • Sampson C.S.
      • Beckett A.
      Novel, inexpensive portable respiratory protection unit (PRPU) for healthcare workers.
      ,
      BBC News Services
      Coronavirus: NI firm helps develop shield for healthcare staff.

       Types of interventions and outcomes

      After the original concept was reported by a Taiwanese physician,
      • Lai H.
      Aerosol box.
      Canelli and colleagues
      • Canelli R.
      • Connor C.W.
      • Gonzalez M.
      • Nozari A.
      • Ortega R.
      Barrier enclosure during endotracheal intubation.
      described a transparent plexiglass barrier enclosure intended to minimise the spread of aerosolised particles during intubation. Their seemingly elegant simulation of a cough (with and without an ‘aerosol box’ in place) demonstrated various particle diffusion patterns and the potential for contamination of personnel charged with airway management. Worldwide, many HCPs have rushed to adopt similar barrier enclosures, and papers describing boxes have been published.
      • Cubillos J.
      • Querney J.
      • Rankin A.
      • Moore J.
      • Armstrong K.
      A multipurpose portable negative air flow isolation chamber for aerosol-generating procedures during the COVID-19 pandemic.
      ,
      • Fonseca E.O.
      • Blanco H.
      • Alvernia J.E.
      New design for aerosol protection during endotracheal intubation in the coronavirus disease 2019 (COVID-19) pandemic era: the “Anti-Aerosol Igloo” (AAI).
      ,
      • Chahar P.
      • Dugar S.
      • Marciniak D.
      Airway management considerations in patients with COVID-19.
      ,
      • Sampson C.S.
      • Beckett A.
      Novel, inexpensive portable respiratory protection unit (PRPU) for healthcare workers.
      ,
      BBC News Services
      Coronavirus: NI firm helps develop shield for healthcare staff.
      Reusable protective shields
      • Fang P.H.
      • Lin Y.Y.
      • Lin C.H.
      A protection tent for airway management in patients with COVID-19 infection.
      ,
      • Martin C.
      • Kloka J.
      • Lotz G.
      • Zacharowski K.
      • Raimann F.J.
      The Frankfurt COVid aErosol pRotEction Dome—COVERED—a consideration for personal protective equipment improvement and technical note.
      ,
      • Kinjo S.
      • Dudley M.
      • Sakai N.
      Modified wake forest type protective shield for an asymptomatic, COVID-19 non-confirmed patient for intubation undergoing urgent surgery.
      and disposable plastic covers for airway management procedures
      • Au Yong PS.
      • Chen X.
      Reducing droplet spread during airway manipulation: lessons from the COVID-19 pandemic in Singapore.
      ,
      • Lim W.Y.
      • Wong P.
      • Ong S.G.K.
      Reducing droplet spread during airway manipulation. Reply to Au Yong and colleagues (Br J Anaesth 2020; 125: e176–e178).
      ,
      • Brown S.
      • Patrao F.
      • Verma S.
      • Lean A.
      • Flack S.
      • Polaner D.
      Barrier system for airway management of COVID-19 patients.
      ,
      • Leyva Moraga F.A.
      • Leyva Moraga E.
      • Leyva Moraga F.
      • et al.
      Aerosol box, an operating room security measure in COVID-19 pandemic.
      ,
      • Francom C.R.
      • Javia L.R.
      • Wolter N.E.
      • et al.
      Pediatric laryngoscopy and bronchoscopy during the COVID-19 pandemic: a four-center collaborative protocol to improve safety with perioperative management strategies and creation of a surgical tent with disposable drapes.
      ,
      • Hill E.
      • Crockett C.
      • Circh R.W.
      • Lansville F.
      • Stahel P.F.
      Introducing the “Corona Curtain”: an innovative technique to prevent airborne COVID-19 exposure during emergent intubations.
      ,
      • Matava C.T.
      • Kovatsis P.G.
      • Lee J.K.
      • et al.
      Pediatric airway management in COVID-19 patients: consensus guidelines from the society for pediatric anesthesia’s pediatric difficult intubation collaborative and the Canadian pediatric anesthesia society.
      that include intubation,
      • Yang S.S.
      • Zhang M.
      • Chong J.J.R.
      Comparison of three tracheal intubation methods for reducing droplet spread for use in COVID-19 patients.
      ,
      • Yang Y.L.
      • Huang C.H.
      • Luk H.N.
      • Tsai P.B.
      Adaptation to the plastic barrier sheet to facilitate intubation during the COVID-19 pandemic.
      • Babazade R.
      • Khan E.S.
      • Ibrahim M.
      • Simon M.
      • Vadhera R.B.
      Additional barrier to protect healthcare workers during intubation.
      • Rehm M.
      • Eichler J.
      • Meidert A.S.
      • Briegel J.
      Protecting health-care workers: use of a body covering transparent sheet during and after intubation of patients with Covid-19.
      placement of supraglottic airway devices,
      • Scapigliati A.
      • Gulli A.
      • Semeraro F.
      • et al.
      How to ventilate during CPR in time of Covid-19?.
      extubation,
      • Matava C.T.
      • Yu J.
      • Denning S.
      Clear plastic drapes may be effective at limiting aerosolization and droplet spray during extubation: implications for COVID-19.
      ,
      • Patino Montoya M.
      • Chitilian H.V.
      Extubation barrier drape to minimise droplet spread.
      ,
      • Hung O.
      • Hung D.
      • Hung C.
      • Stewart R.
      A simple negative-pressure protective barrier for extubation of COVID-19 patients.
      tracheostomy,
      • Foster P.
      • Cheung T.
      • Craft P.
      • et al.
      Novel approach to reduce transmission of COVID-19 during tracheostomy.
      ,
      • Chow V.L.Y.
      • Chan J.Y.W.
      • Ho V.W.Y.
      • et al.
      Tracheostomy during COVID-19 pandemic—novel approach.
      ,
      • Bertroche J.T.
      • Pipkorn P.
      • Zolkind P.
      • Buchman C.A.
      • Zevallos J.P.
      Negative-pressure aerosol cover for COVID-19 tracheostomy.
      bronchoscopy,
      • Pollaers K.
      • Herbert H.
      • Vijayasekaran S.
      Pediatric microlaryngoscopy and bronchoscopy in the COVID-19 era.
      tracheal tube exchange, paediatric airway management,
      • Francom C.R.
      • Javia L.R.
      • Wolter N.E.
      • et al.
      Pediatric laryngoscopy and bronchoscopy during the COVID-19 pandemic: a four-center collaborative protocol to improve safety with perioperative management strategies and creation of a surgical tent with disposable drapes.
      ,
      • Matava C.T.
      • Kovatsis P.G.
      • Lee J.K.
      • et al.
      Pediatric airway management in COVID-19 patients: consensus guidelines from the society for pediatric anesthesia’s pediatric difficult intubation collaborative and the Canadian pediatric anesthesia society.
      ,
      and other aerosol-generating procedures (AGPs)
      • Malik J.S.
      • Jenner C.
      • Ward P.A.
      Maximising application of the aerosol box in protecting healthcare workers during the COVID-19 pandemic.
      ,
      • Cordier P.Y.
      • De La Villeon B.
      • Martin E.
      • Goudard Y.
      • Haen P.
      Health workers’ safety during tracheostomy in COVID-19 patients: homemade protective screen.
      ,
      • Foster P.
      • Cheung T.
      • Craft P.
      • et al.
      Novel approach to reduce transmission of COVID-19 during tracheostomy.
      ,
      • Chow V.L.Y.
      • Chan J.Y.W.
      • Ho V.W.Y.
      • et al.
      Tracheostomy during COVID-19 pandemic—novel approach.
      ,
      • Bertroche J.T.
      • Pipkorn P.
      • Zolkind P.
      • Buchman C.A.
      • Zevallos J.P.
      Negative-pressure aerosol cover for COVID-19 tracheostomy.
      have been proposed. More recently, handmade and three-dimension printed boxes (Fig 2), adapted neonatal incubator hoods,
      • Rahmoune F.C.
      • Ben Yahia M.M.
      • Hajjej R.
      • Pic S.
      • Chatti K.
      Protective device during airway management in patients with coronavirus disease 2019 (COVID-19).
      and even carton–plastic enclosures have been introduced.
      • Lai Y.Y.
      • Chang C.M.
      A carton-made protective shield for suspicious/confirmed COVID-19 intubation and extubation during surgery.
      Many of these devices provide limited or no access for an assistant, and no or limited accommodations for advanced airway management techniques (e.g. flexible scope-aided tracheal intubation).
      Fig 2
      Fig 2Airway boxes and drapes. (a–d) Credit: idea by: Pasquale De Negri MD, Giugliano, Napoli, Italy; courtesy Clelia Esposito MD, Napoli, Italy. Patient granted permission for use of picture. (e) Credit: Dr Idea: Antonio Lamberto, coronavirus disease (COVID) hospital di Barcellona Pozzo di Gotto, Messina, Italy ( [email protected] ); project: Studio di Architettura Romagnolo, Messina, Italy ( [email protected] ); manufacturing: Vision (Barcellona Pozzo di Gotto, Italy). The airway boxes were donated for free to COVID hospitals. (f) Simulated paediatric induction using airway box paediatric version. (g) Paediatric intubation using videolaryngoscope and plastic cover. (f–g) Courtesy Lorena Pasini MD, Bologna, Italy. (a–b) Patient expressed consent for use of picture. (d) Human volunteer expressed his consent for use of picture.
      Feldman and colleagues
      • Feldman O.
      • Meir M.
      • Shavit D.
      • Idelman R.
      • Shavit I.
      Exposure to a surrogate measure of contamination from simulated patients by emergency department personnel wearing personal protective equipment.
      concurred with the findings of Canelli and colleagues
      • Canelli R.
      • Connor C.W.
      • Gonzalez M.
      • Nozari A.
      • Ortega R.
      Barrier enclosure during endotracheal intubation.
      in adult and paediatric simulated scenarios. This group confirmed that many airway procedures are AGPs. Extubation may generate more aerosol particles than intubation,
      • Sorbello M.
      • El-Boghdadly K.
      • Di Giacinto I.
      • et al.
      The Italian coronavirus disease 2019 outbreak: recommendations from clinical practice.
      and HCPs charged with airway management have higher exposure and increased transmission risk, and should don airborne-level PPE when performing AGPs.
      • Sorbello M.
      • Di Giacinto I.
      • Falcetta S.
      • Greif R.
      Ventilation and airway management during cardiopulmonary resuscitation in COVID-19 era.
      ,
      • World Health Organization
      Clinical management of severe acute respiratory infection (SARI) when COVID-19 disease is suspected: interim guidance.
      ,
      • Wilson N.M.
      • Norton A.
      • Young F.P.
      • Collins D.W.
      Airborne transmission of severe acute respiratory syndrome coronavirus-2 to healthcare workers: a narrative review.
      Based on these findings, it has been suggested that in cases where adequate PPE is not available, barrier enclosures might mitigate HCP exposure. However, because of the large variability of the approaches, the often-small sample sizes, sparse patient data, and no evidence of decrease viral transmission with their use, many questions remain to be addressed. Therefore, in this narrative, the expert panel proposes that the following issues should be investigated in a controlled fashion before widespread adoption or recommendation of barrier interventions.

       Is SARS-CoV-2 spread by airborne transmission (via suspended droplets or aerosols)?

      Whilst still under investigation, data from the SARS and Middle Eastern respiratory syndrome (MERS) outbreaks
      • Sorbello M.
      • Di Giacinto I.
      • Falcetta S.
      • Greif R.
      Ventilation and airway management during cardiopulmonary resuscitation in COVID-19 era.
      and more recent reports
      • van Doremalen N.
      • Bushmaker T.
      • Morris D.H.
      • et al.
      Aerosol and surface stability of SARS-CoV-2 as compared with SARS-CoV-1.
      • Anfinrud P.
      • Stadnytskyi V.
      • Bax C.E.
      • Bax A.
      Visualizing speech-generated oral fluid droplets with laser light scattering.
      • Yang X.
      • Yu Y.
      • Xu J.
      • et al.
      Clinical course and outcomes of critically ill patients with SARS-CoV-2 pneumonia in Wuhan, China: a single-centered, retrospective, observational study.
      • Banik R.K.
      • Ulrich A.K.
      Evidence of short-range aerosol transmission of SARS-CoV-2 and call for universal airborne precautions for anesthesiologists during the COVID-19 pandemic.
      • Bowdle A.
      • Munoz-Price L.S.
      Preventing infection of patients and healthcare workers should be the new normal in the era of novel coronavirus epidemics.
      strongly suggest airborne transmission results in HCP exposure, especially during airway management procedures.
      • Tran K.
      • Cimon K.
      • Severn M.
      • Pessoa-Silva C.L.
      • Conly J.
      Aerosol generating procedures and risk of transmission of acute respiratory infections to healthcare workers: a systematic review.
      ,
      • Morawska L.
      • Milton D.K.
      It is time to address airborne transmission of COVID-19.
      Disease spread and clinical illness incidence appear to be directly proportional to viral load and exposure time,
      • Wilson N.M.
      • Norton A.
      • Young F.P.
      • Collins D.W.
      Airborne transmission of severe acute respiratory syndrome coronavirus-2 to healthcare workers: a narrative review.
      which are higher and longer during airway management
      • Tran K.
      • Cimon K.
      • Severn M.
      • Pessoa-Silva C.L.
      • Conly J.
      Aerosol generating procedures and risk of transmission of acute respiratory infections to healthcare workers: a systematic review.
      because of the proximity of the HCP to the airway.

       Do ‘aerosol boxes’ and other barrier-enclosure systems effectively prevent aerosol spread?

      Aerosols are defined as a suspension of small particles (0·001–100 μm) that may carry the live virus for up to 3 h.
      • van Doremalen N.
      • Bushmaker T.
      • Morris D.H.
      • et al.
      Aerosol and surface stability of SARS-CoV-2 as compared with SARS-CoV-1.
      As demonstrated by Canelli and colleagues
      • Canelli R.
      • Connor C.W.
      • Gonzalez M.
      • Nozari A.
      • Ortega R.
      Barrier enclosure during endotracheal intubation.
      and Raimann and colleagues,
      • Raimann F.
      • Kloka J.
      • Martin C.
      • Gilla P.
      • Lotz G.
      • Zacharowski K.
      Visualized effect of the Frankfurt COVid aErosol pRotEction dome—COVERED.
      barriers, such as aerosol boxes and plastic covers, may limit large droplet spread. However, there has been no evidence presented that they adequately protect HCPs against aerosolised viral particles. A study with schlieren imaging (a passive imaging method for direct visualisation of refractive index changes used to assess small particle spread) of a coughing volunteer showed that considerable amounts of air moved out of the aerosol box from the distal open end and through the operative holes.
      • Filho W.A.
      • Teles T.
      • da Fonseca M.R.S.
      • et al.
      Barrier device prototype for open tracheotomy during COVID-19 pandemic.
      ,
      • Dalli J.
      • Khan M.F.
      • Marsh B.
      • Nolan K.
      • Cahill R.A.
      Evaluating intubation boxes for airway management.
      Simulations with e-cigarettes and propylene glycol vapours (that contain large aerosol particles ranging from 40 to 200 μm in diameter) suggest that neither the boxes nor the plastic barriers provide sufficient protection from the spread of aerosols, and may even channel or contain them into a higher concentration close to HCPs managing the airway (Supplementary Appendix 3, Video 1). Trapped aerosols may later be unknowingly released upon removal of the barrier (‘secondary aerosolisation’). Alternative solutions might include the addition of plastic tents to the boxes,
      • Lim W.Y.
      • Wong P.
      • Ong S.G.K.
      Reducing droplet spread during airway manipulation. Reply to Au Yong and colleagues (Br J Anaesth 2020; 125: e176–e178).
      ,
      • Matava C.T.
      • Yu J.
      • Denning S.
      Clear plastic drapes may be effective at limiting aerosolization and droplet spray during extubation: implications for COVID-19.
      ,
      • Patino Montoya M.
      • Chitilian H.V.
      Extubation barrier drape to minimise droplet spread.
      ,
      • Fang P.H.
      • Lin Y.Y.
      • Lin C.H.
      A protection tent for airway management in patients with COVID-19 infection.
      ,
      • Gore R.K.
      • Saldana C.
      • Wright D.W.
      • Klein A.M.
      Intubation containment system for improved protection from aerosolized particles during airway management.
      ,
      CONMED
      Demonstration of simulated pediatric patient with plastic tent and smoke extractor.
      negative-pressure systems,
      • Rahmoune F.C.
      • Ben Yahia M.M.
      • Hajjej R.
      • Pic S.
      • Chatti K.
      Protective device during airway management in patients with coronavirus disease 2019 (COVID-19).
      ,
      • Sorbello M.
      • Di Giacinto I.
      • Falcetta S.
      • Greif R.
      Ventilation and airway management during cardiopulmonary resuscitation in COVID-19 era.
      ,
      • Swart R.
      • Strydom C.
      The qualitative evaluation of the limitation of aerosol spread by a transparent intubation box.
      ,
      • Hung O.
      • Hung D.
      • Hung C.
      • Stewart R.
      A simple negative-pressure protective barrier for extubation of COVID-19 patients.
      ,
      • Martin C.
      • Kloka J.
      • Lotz G.
      • Zacharowski K.
      • Raimann F.J.
      The Frankfurt COVid aErosol pRotEction Dome—COVERED—a consideration for personal protective equipment improvement and technical note.
      ,
      • Pollaers K.
      • Herbert H.
      • Vijayasekaran S.
      Pediatric microlaryngoscopy and bronchoscopy in the COVID-19 era.
      ,
      • Convissar D.
      • Chang C.Y.
      • Choi W.E.
      • Chang M.G.
      • Bittner E.A.
      The Vacuum Assisted Negative Pressure Isolation Hood (VANISH) system: novel application of the Stryker Neptune suction machine to create COVID-19 negative pressure isolation environments.
      ,
      • Sorbello M.
      • El-Boghdadly K.
      • Di Giacinto I.
      • et al.
      The Italian coronavirus disease 2019 outbreak: recommendations from clinical practice.
      • Feldman O.
      • Meir M.
      • Shavit D.
      • Idelman R.
      • Shavit I.
      Exposure to a surrogate measure of contamination from simulated patients by emergency department personnel wearing personal protective equipment.
      • World Health Organization
      Clinical management of severe acute respiratory infection (SARI) when COVID-19 disease is suspected: interim guidance.
      • Wilson N.M.
      • Norton A.
      • Young F.P.
      • Collins D.W.
      Airborne transmission of severe acute respiratory syndrome coronavirus-2 to healthcare workers: a narrative review.
      or rapid vacuum aspiration, which in itself might be more effective than the use of barriers (see Marriott Extractor, Supplementary Appendix 3, Video 2).
      • Tso M.
      Coronavirus: Kiwi doctor invents extractor system to protect healthworkers from Covid-19.
      ,
      CONMED
      Demonstration of simulated pediatric patient with plastic tent and smoke extractor.
      The following are the supplementary data related to this article:

       Are the rigid boxes ergonomically practical?

      Although many of the aerosol box simulations have been performed in an operating theatre environment, these devices may be used in other patient settings, with different patient surfaces, sizes, and types (e.g. ICU, radiology suite, and ambulance). A box placed above the patient's head might not fit (e.g. an obese patient); may be uncomfortable; or provoke claustrophobia, anxiety, restlessness, and combativeness. Furthermore, they are not usable in situations of severe respiratory distress, where patients are often sitting upright or semi-recumbent to maintain respiratory function. Demonstrations of barrier models that are wider, possibly more stable, that allow for ramped positioning and increased manoeuvrability have been suggested,
      • Malik J.S.
      • Jenner C.
      • Ward P.A.
      Maximising application of the aerosol box in protecting healthcare workers during the COVID-19 pandemic.
      ,
      • Asokan K.
      • Babu B.
      • Jayadevan A.
      Barrier enclosure for airway management in COVID-19 pandemic.
      but there remains no evidence that they improve airway management performance. If an intubation introducer
      • Kearsley R.
      Intubation boxes for managing the airway in patients with COVID-19.
      or a bulky or hyper-angulated videolaryngoscope is used, then there may not be sufficient intra-box space to allow for unencumbered manipulation.
      • Gould C.L.
      • Alexander P.D.G.
      • Allen C.N.
      • McGrath B.A.
      • Shelton C.L.
      Protecting staff and patients during airway management in the COVID-19 pandemic: are intubation boxes safe?.
      A simulation study comparing intubation success with or without two generations of aerosol boxes demonstrated that the boxes were associated with higher intubation failure rates and prolonged intubation times.
      • Begley J.L.
      • Lavery K.E.
      • Nickson C.P.
      • Brewster D.J.
      The aerosol box for intubation in coronavirus disease 2019 patients: an in-situ simulation crossover study.
      In contrast, other simulations have shown that the use of powered respirator PPE does not affect the time to intubation and first-pass success of videolaryngoscope-aided tracheal intubation.
      • Schumacher J.
      • Arlidge J.
      • Dudley D.
      • Sicinski M.
      • Ahmad I.
      The impact of respiratory protective equipment on difficult airway management: a randomised, crossover, simulation study.
      We must also consider how monitor cables, i.v. tubing, breathing circuits, suction tubing, and bedding might interfere with barrier use and be disrupted by barrier placement and removal. Use of advanced features of supraglottic airway devices (i.e. gastric tube placement, position-check tests, and optically guided tracheal intubation) might be limited.
      • Sorbello M.
      • Di Giacinto I.
      • Falcetta S.
      • Greif R.
      Ventilation and airway management during cardiopulmonary resuscitation in COVID-19 era.
      A concern for accidental tracheal extubation through entanglement during barrier removal must be considered. Appreciating the time pressure, cognitive load, and stress associated with airway management in patients with anatomically or physiologically difficult airways,
      • Sorbello M.
      • Afshari A.
      • De Hert S.
      Device or target? A paradigm shift in airway management: implications for guidelines, clinical practice and teaching.
      and the limitations imposed by PPE,
      • Kearsley R.
      Intubation boxes for managing the airway in patients with COVID-19.
      the addition of another physical barrier seems counter-intuitive.
      It has been argued that physical barriers might be more useful for the extubation phase of airway management, but controlled investigations are likewise needed.
      • Sorbello M.
      • Di Giacinto I.
      • Falcetta S.
      • Greif R.
      Ventilation and airway management during cardiopulmonary resuscitation in COVID-19 era.
      ,
      • Hung O.
      • Hung D.
      • Hung C.
      • Stewart R.
      A simple negative-pressure protective barrier for extubation of COVID-19 patients.
      At the time of anaesthetic emergence, still more questions arise: How will a waking patient react to a confining barrier? What happens in cases of patient coughing after extubation or the need for airway suctioning? If emergency reintubation is needed, can the operator manoeuvre properly? Will the confines of the barrier enclosure hinder the use of an airway exchange catheter? What are the proper procedures for managing airway compromise on awakening?

       Could barrier enclosures be a risk during airway emergencies?

      Cases of failed tracheal intubation or extubation requiring reintubation, rescue manoeuvres (including the use of alternative devices, such as face mask or supraglottic airway ventilation), or emergency surgical airway access may be necessary. One simulation has demonstrated that in case of difficult airway resuscitation, the ability of an assistant to aid the intubator was encumbered.
      • Endersby R.V.W.
      • Ho E.C.Y.
      • Spencer A.O.
      • Goldstein D.H.
      • Schubert E.
      Barrier devices for reducing aerosol and droplet transmission in COVID-19 patients.
      If a barrier must be rapidly removed during an airway emergency, then this may cause delay or be hazardous to the patient, airway operator, or assistant.
      • Chan A.
      Should we use an “aerosol box” for intubation?.
      It is not difficult to demonstrate through simulation how this approach could make an airway crisis more difficult to handle, including the added task of barrier-enclosure removal to provide adequate access to the patient (see Supplementary Appendix 3, Video 3). Furthermore, should cardiopulmonary resuscitation and defibrillation be needed, the box or tent may represent a flammable oxygen reservoir, increasing the risk of fire.
      • Francom C.R.
      • Javia L.R.
      • Wolter N.E.
      • et al.
      Pediatric laryngoscopy and bronchoscopy during the COVID-19 pandemic: a four-center collaborative protocol to improve safety with perioperative management strategies and creation of a surgical tent with disposable drapes.
      ,
      • Nolan J.P.
      • Monsieurs K.G.
      • Bossaert L.
      • et al.
      European Resuscitation Council COVID-19 guidelines executive summary.
      The following is the supplementary data related to this article: