key: cord-0976174-rqm0p19e
authors: Baker, Paul A.; Peyton, James; von Ungern‐Sternberg, Britta S.
title: What’s inside the box? Or shall we think outside the box?
date: 2020-08-28
journal: Paediatr Anaesth
DOI: 10.1111/pan.13932
sha: a94b81b677d8002ed6051dfd950f56ca8076a9be
doc_id: 976174
cord_uid: rqm0p19e

nan

With the deadly and highly transmissible SARS-CoV-2 virus causing the COVID-19 pandemic, there is global concern about the danger of contaminating healthcare workers (HCW), particularly during airway management of infected patients. In this edition of Pediatric Anesthesia, Bryant and Tobias report a laboratory study where there was up to 99.2% decrease of artificial aerosol particles measured outside compared with inside an enclosed clear intubation box using augmented gas flow (suction). 1 At first glance, the concept of a barrier over the patient during airway management seems like a simple and logical option in terms of protecting practitioners from viral infection. This concept has inspired a range of barrier solutions to protect HCWs from infection during intubation. Plastic sheets and intubation boxes made of Perspex or cardboard are proposed as aerosol barriers, and their use had been propagated heavily on social media during the first three months of the COVID-19 pandemic. The repeated mentioning of this "simple" solution to the highly feared transmission to HCWs led to a fast global spread without any clinical evidence of efficacy, usability, and decreased transmission rates. It may be that some or all of these ideas have merit, but a scientific approach to their evaluation of benefit and risk has been largely lacking.

It is assumed that placing a barrier over an infected patient during 

Intubation is reported to be a high-risk procedure for aerosol release and transmission of infection to HCWs. Supporting evidence for this comes from a systematic review. 3 That review, 

Particle spread during laryngoscopy with a simulated cough can be studied using fluorescent dye and a manikin. Without an intubation box, PPE worn by the laryngoscopist became extensively contaminated with the dye. The dye was not seen when the experiment was repeated with the box in place. PPE should be regarded as part of a package which includes adequate clothing, fit-tested N95/100 mask and eye protection plus training, handwashing, social distancing techniques and appropriate environmental conditions with surface cleaning, air conditioning, and isolation techniques. There is currently no evidence that the addition of a patient barrier is necessary to improve enhanced PPE.

Several publications have noted that solid boxes restrict hand and arm motions and increase the time taken to intubate, which may place patients at risk from hypoxemia during intubation. Damage to PPE from arm ports, difficulty using a bougie and other airway adjuncts, adverse influence on first-pass success, viral spread following removal of the barrier, and problems associated with size variability of the patient and laryngoscopist are also listed as potential prob- with prolonged intubation attempts. All intubations were performed by experienced providers. In those 4 cases, the barrier was removed.

One of the fourteen children had airway-related pathology (a 9-dayold with a neck mass) and that patient briefly desaturated to 66% on induction. No other patients experienced oxygen desaturation.

To put this into context, since 2012, 1.1% of tracheal intubations performed at Boston Children's Hospital have met criteria for entry into the Pediatric Difficult Intubation Registry. Even though the number of COVID-19-positive or COVID-19-suspected patients is low, it appears that they may have a higher incidence of difficulties during intubation than our background population. The most obvious difference in the techniques to intubate them is the use of an aerosol/droplet barrier.

Data collection for these patients is ongoing in order to get a more complete picture as the number of cases performed increases with time.

It is clear that there are many unanswered questions concerning airway barriers. Already, some hospitals have adopted the use of airway barriers in their recommendations and protocols. We caution about the early adoption of these techniques in the absence of any supporting clinical evidence. We also urge clinicians to carefully balance the benefits and risks of adopting techniques which could adversely affect the airway management for any patient. We should rather think outside the box and focus on the safety of the HCW by ensuring appropriate PPE. A patient barrier to aerosol should not become a barrier to safe airway management.

airway child, airway difficult, equipment devices

BS vUS is a section editor for Pediatric Anesthesia. 

5 Department of Anesthesia and Pain Management, Perth Children's Hospital

Telethon Kid's Institute

Enclosure with augmented airflow to decrease risk of exposure to aerosolized pathogens including coronavirus during endotracheal intubation. Can the reduction in aerosolized particles be quantified? Pediatric Anesthesia

An integrated model of infection risk in a health-care environment

Aerosol generating procedures and risk of transmission of acute respiratory infections to healthcare workers: a systematic review

Expert Recommendations for Tracheal Intubation in Critically ill Patients with Noval Coronavirus Disease

The aerosol box for intubation in COVID-19 patients: an in-situ simulation crossover study