Impact of Aerosol Box Use During Cardiopulmonary Arrest: A Multicenter Study

Problem to be addressed. The overwhelming scale and severity of the Coronavirus Disease 2019 (COVID-19) pandemic has presented a serious threat to the health of frontline health care workers (HCWs). Aerosol-generating medical procedures (AGMPs), such as bag-valve-mask (BVM) ventilation, endotracheal intubation (ETI), and cardiopulmonary resuscitation (CPR) are commonly required for critically ill COVID-19 patients. AGMPs produce airborne particles, contributing to the disproportionately high risk of infection amongst HCWs working in acute care areas. Strategies to mitigate HCWs exposure to and infection from COVID-19 are required to maintain the integrity of the healthcare workforce. To minimize HCW exposure during AGMPs, aerosol box devices have been developed to provide a physical barrier between the patient and the HCW, with the intent of shielding HCWs from disease particles.

The aerosol box, and its various different adaptations, have been implemented by hospitals around the world for managing critically ill patients with COVID-19. Studies to date have demonstrated that aerosol box use potentially reduces spread of aerosolized particles, but its use is also associated with technical challenges. Studies to date have focused primarily on the task of ETI, without any evidence describing the impact of aerosol box use on chest compressions (CC). Furthermore, most studies suffer from small sample sizes, provided minimal (or no) training on aerosol box use, recruited individuals (and not resuscitation teams) as participants, failed to quantify the degree of contamination on providers, or failed to measure airborne particle counts. The study team recently completed a multicenter randomized trial comparing aerosol box vs. no box use and demonstrated delayed time to intubation with aerosol box use. However, the study was done in a limited context (short procedure, airway team of 2 providers, CC not measured), thus making generalizability to team-based resuscitative care questionable. To date, there have been no single or multicenter studies concurrently evaluating the effect of aerosol box use on CPR quality, airborne particle concentration, and HCW contamination during team-based resuscitative care. As a consequence, it is still unknown if aerosol boxes are effective in protecting HCWs, and if aerosol box use negatively impacts care during cardiopulmonary arrest.

The importance and relevance of simulation-based aerosolization studies is highly dependent upon the use of a realistic model for aerosolization. Several groups have reported aerosolization devices in the form of cough simulation devices ranging from hand-held syringes, nasal atomizers, spray guns, bag-valve masking and more advanced air flow-based devices to simulate cough. Unfortunately, none of these cough simulators were designed for user-controlled settings of respiratory mechanics (eg. respiratory rate, volume, flow) while also allowing for performance of intubation and chest compressions. This study represents the first aerosol box study to use an aerosolization device comprised of a respiratory simulator allowing for control of respiratory mechanics that closely mimic those of a real patient, while concurrently allowing performance of AGMPs.

Our study will provide evidence to: (a) evaluate if use of an aerosol box adversely affects time to completion and quality of critical resuscitation tasks; and (b) determine if aerosol boxes are effective in reducing airborne particle counts and provider contamination during team-based cardiac arrest resuscitation. Our long-term goal is to provide empiric evidence to enhance HCW safety while delivering high quality care during cardiopulmonary resuscitation. This will be accomplished by creating a cardiac arrest scenario within a controlled simulated clinical environment, as conducting a similar study on real patients would be fraught with challenges and risks.

Why is a trial needed now? New COVID-19 variants, variable uptake of immunizations, and waning immunity amongst the immunized population contribute to the persistent threat of the COVID-19 pandemic. We've learned how quickly the pandemic can change course, and how it is important to plan for future pandemics caused by different viruses. Now, more than ever, it is critical to identify strategies to protect healthcare workers from infection. HCW infection has led to workforce shortages that negatively impact patient outcome. Aerosol boxes have been used in some parts of the world to protect HCWs during the pandemic, but existing evidence gaps have prevented its widespread adoption. A better understanding of particle dispersion patterns, HCW contamination patterns, and impact on clinical task performance during resuscitative care will help to inform international cardiac arrest guidelines.

How will the results of this trial be used? Research assessing strategies to mitigate HCW risks of contamination are critical to maintaining a viable healthcare workforce during the pandemic. The proposed study provides further evidence informing the potential use of aerosol boxes during simulated cardiopulmonary arrest. The research will be the first to provide a quantitative measure of airborne particles and HCW contamination patterns in conjunction with clinically important outcome measures. In combination, these metrics provide key information that will inform clinical practice, institutional airway management and cardiac arrest policies. Through partnerships (e.g. Heart and Stroke Foundation of Canada) and longitudinal engagement of key local and national public health agency stakeholders, the results of this study will be shared with policymakers to enable evidence-based adaptations to clinical protocols. Existing partnerships within the International Network for Simulation-based Pediatric Innovation, Research and Education (INSPIRE network) will enable rapid dissemination of aerosol box training material across all continents if results are positive. As an author on international COVID-19 and cardiac arrest resuscitation guidelines, the PI will engage stakeholders to ensure results inform future International Liaison Committee on Resuscitation (ILCOR) guidelines for or against use of the aerosol box.

Trial design. A prospective, randomized controlled trial will be conducted across five sites in North America. Simulation-based research confers the advantage of answering research questions without risk of harm to HCWs or patients. Three participants will be recruited to play the roles of airway provider, and two CPR providers in the management of a simulated, critically ill COVID-19 patient. CPR providers will be trained to provide CPR coaching to each other. Two trained research assistants will participate in the resuscitation team as a team leader and bedside nurse/airway assistant and perform these roles in a standardized manner. Team leaders will not provide any guidance or coaching on CPR quality. Participants will be randomized by team into either the control arm (i.e. no aerosol box) or the intervention arm (i.e. use of aerosol box) (Figure 1). Following randomization, all participants will view a short video orienting them to the simulated clinical environment. Intervention arm teams will view an additional 5-minute video orienting them to the design of the aerosol box and including expert-modeled demonstration of strategies for optimal airway management and delivery of CPR. This includes how to move the patient within the aerosol box to optimize delivery of CPR. The training video will be filmed in English and French to permit viewing across all study sites. After viewing the video, participants will work in teams to practice intubation and CPR (with aerosol box in place) for a maximum of 15 minutes, providing them opportunity to coordinate their movements to optimize efficiency. After each procedure, they will receive feedback from a local airway and aerosol box expert (i.e. site investigator). Control arm teams will also have opportunity to practice intubation and/or CPR for 15 min (without aerosol box). After orientation and training, teams will participate in two sequential simulation scenarios. The order of scenario delivery will be randomized to eliminate scenario order as a potential confounder. At the end of the entire session, participants will receive an educational debriefing to discuss performance issues, infection control measures, and technical skills using a blended-method approach to debriefing. The Investigators elected not to use a cross-over study design because of insufficient washout time (between scenarios) and the potential carry-over effects of learning from the prior scenario influencing performance in the subsequent scenario.