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How did an improvised medical device end up in widespread global use in May only to be left neglected in hospital offices 4 months later? In early 2020, anxiety escalated as the COVID-19 pandemic evolved. As SARS-CoV-2 infections and word of deaths of healthcare workers rippled through social media, clinicians at high risk of infection—those managing airways—began to look for ways to protect themselves. Concern about the adequacy of personal protective equipment was swiftly followed by the adoption of new equipment intended for staff safety. Transparent acrylic ‘aerosol boxes’ were novel protective devices intended to provide an additional layer of protection for clinicians from exposure to virus during the intubation of patients with COVID-19.1 The assumption was that any additional layer of protection would only add to the safety for the patients and clinical staff. However, there is increasing evidence to the contrary.
With the publication of the study by Azhar et al, the evidence now strongly suggests that aerosol boxes increase intubation times, restrict movement and likely decrease first pass intubation success rate.2 A total of 36 post graduate emergency medicine trainees attempted videolaryngoscopy-assisted intubation of manikins in a simulated environment, while wearing standard PPE for aerosol generating procedures. The primary outcome measure was measurement of contamination of the room and PPE, but arguably the more important outcome measure is the risk to the patient from prolonged or repeated intubation attempts due to restriction of movement from the device. These findings compliment the first study published on these devices by Begley et al, demonstrating a significant increase in intubation time by consultant anaesthetists in a very similar simulated setting.3 Azhar et al’ study was underpowered to detect a statistically significant difference in the first pass success rate, but the observation of more attempts in the aerosol box group is consistent with the observations of Begley et al in simulation of these devices. In short, Azhar et al’s results support existing evidence that these devices are unsafe for patients with COVID-19; where experience confirms that these patients are prone to precipitous desaturation and clinicians do not have the luxury of tolerating prolonged apnoeic time.4 The ED is also an environment where first-pass success at intubation is critically important to patient safety.5 A recent scoping review found that these aerosol boxes increase task complexity, are a barrier to airway management, may increase transmission, compromise PPE and offered no protection against aerosols.6
Azhar et al were successful in demonstrating that aerosol boxes may reduce droplet contamination of PPE using visual inspection. Nevertheless, this did not translate to the more important outcome of reduced clinician exposure after PPE removal. Most importantly, the only quantitative study on the protective properties of the aerosol boxes demonstrated that these devices paradoxically increase aerosol contamination of the intubating clinician, which was attributed to the Bernoulli principle.7
Further to the growing evidence of increased staff risk from these devices, Azhar et al’s findings of possible increased contamination of the forearms (even after correctly doffing PPE) compliments the PPE damage at the forearms observed in the original paper by Begley et al. Azhar et al’s results are consistent with existing evidence that these devices may endanger the intubating clinician.
It is entirely understandable that clinicians sought to create and use these novel devices from a genuine desire to reduce their risks at a time of unprecedented anxiety. The process of cobbling together new devices from existing materials has been termed “MacGvyering” from the eponymous 1980’s crime-fighting TV hero. In a time of increased clinician stress and anxiety8 novel equipment, developed through either MacGyvering or outright invention become commonplace. Necessity, as they say, is the mother of invention. Nevertheless, all devices require critical evaluation, even during a pandemic, to ensure there are no potential seen or unseen hazards in their use. The perception that more equipment leads to more safety is flawed, with safety science being littered with examples of a paradoxical loss of safety from the introduction of a new safety device.9 In the first half of 2020, these boxes were rapidly distributed to hospitals worldwide and obtained Emergency Use Authorization (EUA) from the United States Food and Drug Administration. This occurred despite the devices having an evidence-free basis and widespread concerns from clinicians around their safety risk to both staff and patients. This EUA has recently been withdrawn citing Simpson et al and Begley et al. This leads us to ponder: How do we practice evidence-based medicine in the COVID-19 landscape?
It appears that the standards of evidence have changed, with medical therapies now rushed into practice after online publication without peer review.10 When governments direct clinicians to change their practice based on a press release, it is hardly surprising that a device that made clinicians feel safer found its way into global use with minimal prior research into its safety.11 The pandemic has highlighted known inefficiencies in conventional medical publishing. At its best, the medical community is rapidly transforming EBM with real-time data release, open-access prepress publication, and social-media-based open peer review. At its worst, the profession abandons EBM in favour of intuitive decision-making and political pressure.
Despite the hasty adoption of many medications and treatments because of unclear outcome measures, we are already very clear what the metrics should be for devices introduced into clinical practice for airway management. These include measurement of first pass success rates and times to intubation which are already known to significantly increase the risks of serious complications to patients. Having safe, simple, robust and reliable procedures during the airway management processes of this pandemic is a consistent feature of recent expert guidelines.12 13 Innovation has obvious merit, but novel equipment needs to be viewed with caution and closely examined for strong EBM principles especially in the absence of reliable evidence to support their safety and efficacy.14 We believe that limited EUAs maybe appropriate in some instances, but only when associated with trials of effectiveness and safety based on concrete metrics. Where possible before that, there needs to be evidence of safety away from a clinical setting with a process of testing and scaled introduction using a defined framework.15
Certainly, a genuine fear motivated the search for the perception of safety. An interesting result in Azhar’s study is that the aerosol box made clinicians feel safer (even though they were not). Humans are poor judges of risk; the things that make us feel safe may actually place us in danger. A fundamental lesson is that we must not let our emotions override critical thinking when trying to protect ourselves and our patients. The assumption that a pandemic should cause us to abandon scientific inquiry and critical thinking is without merit. The stakes are higher than ever; we must be more critical of the evidence and our decision-making, not less. If we had critical thinking prevail in this case, then we may have avoided exposing numerous clinicians and patients to the unnecessary risk of these devices.
Footnotes
Handling editor Katie Walker
Twitter @drdavidbrewster, @SpontVentGA
Contributors All three authors contributed to the writing and planning of this paper. Nil additional contributors.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Patient consent for publication Not required.
Provenance and peer review Commissioned; internally peer reviewed.