key: cord-0932490-d5xam4kb authors: Schumacher, J.; Arlidge, J.; Dudley, D.; Sicinski, M.; Ahmad, I. title: The impact of respiratory protective equipment on difficult airway management: a randomised, crossover, simulation study date: 2020-05-28 journal: Anaesthesia DOI: 10.1111/anae.15102 sha: ce9d59fbae4d843b172405af0f63d40983dc0d04 doc_id: 932490 cord_uid: d5xam4kb The current international COVID‐19 health crisis underlines the importance of adequate and suitable personal protective equipment for clinical staff during acute airway management. This study compares the impacts of standard air‐purifying respirators and powered air‐purifying respirators during simulated difficult airway scenarios. Twenty‐five anaesthetists carried out four different standardised difficult intubation drills, either unprotected (control), or wearing a standard or a powered respirator. Treatment times and wearer comfort were determined and compared. In the wearer comfort evaluation form, operators rated mobility, noise, heat, vision and speech intelligibility. All anaesthetists accomplished the treatment objectives of all study arms without adverse events. Total mean (SD) intubation times for the four interventions did not show significant differences between the powered and the standard respirator groups, being 16.4 (8.6) vs. 19.2 (5.2) seconds with the Airtraq™; 11.4 (3.4) vs. 10.0 (2.1) seconds with the videolaryngoscope; 39.2 (4.5) vs. 40.1 (4.8) seconds with the fibreoptic bronchoscope scope; and 15.4 (5.7) vs. 15.1 (5.0) seconds for standard tracheal intubation by direct laryngoscopy, respectively. Videolaryngoscopy allowed the shortest intubation times regardless of the respiratory protective device used. Anaesthetists rated heat and vision significantly higher in the powered respirator group; however, noise levels were perceived to be significantly lower than in the standard respirator group. We conclude that standard and powered respirators do not significantly prolong simulated advanced intubation procedures. Airway management in critically ill patients contaminated with chemical, biological radiological or nuclear substances requires personal protective equipment (PPE) [1, 2] . The past two decades have focused on the hazards for frontline medical staff posed by the deliberate release of weaponised chemical, biological, radiological or nuclear substances. The occupational hazards of healthcare workers during naturally occurring pandemics, however, have a much longer history. Bio-aerosol infection risks to healthcare professionals may arise from direct patient contact, but are especially high during aerosol-generating procedures such as: intubation; bronchoscopy; noninvasive ventilation; high-frequency oscillating ventilation; induction of sputum; and surgical procedures involving high speed devices. Notably, during the 2003 severe acute respiratory distress syndrome pandemic, 21% of those who had the disease were healthcare workers [3] . In Canada, this was reported as 43%, with anaesthetists being amongst the highest risk group [3, 4] . Public Health England [5] is drawn into the mask through a filter either when the wearer breathes in, or from a power-assisted filtering device [12] . The visor provides protection against particulates, splashes and gases, yet should allow good visibility for the wearer. A half mask respirator is a facepiece which only covers the nose, mouth and the chin of the wearer, held in place with adjustable straps [12] . Half masks do not have a visor for eye protection and provide lower assigned protection factor levels than full facemasks [13] . In recent years, powered air-purifying respirators have been introduced; a complete powered filtering device consisting of a battery-operated turbo unit, a filter and a loose-fitting headtop, for example, a hood or visor [12] . Although they are bulkier and more expensive, powered respirators eliminate the need for fit testing and problems of heat build-up, dead-space ventilation and airflow resistance [12] [13] [14] . This is the first study comparing the impact of modern powered respirators and standard respirators on simulated difficult airway procedures. The primary outcome measure of this study was as the difference in intubation times for various airway management procedures, with wearer comfort a secondary outcome. Trust Research and Development approval. The study did not require review by a research ethics committee, as the research only involved staff as participants. The objective was to recruit 25 anaesthetists within our hospital Trust whose duties involved responding to trauma calls. Exclusion criteria for the participants included those suffering from asthma, claustrophobia or a history of panic disorder. Twenty-five subjects gave written and informed Within the study period, we were able to recruit 25 volunteers. All anaesthetists participating in the study successfully accomplished the treatment objectives of all the study arms. All interventions ended with successful tracheal tube placement. The treatment times are displayed in Table 1 . Intubation times were significantly shorter when using videolaryngoscopy, regardless of the respiratory protective device used. Airway management times of the Airtraq group, the videolaryngoscopy and the fibreoptic intubation Anaesthetists rated their personal sensation of heat buildup and perceived vision significantly higher in the powered respirator group; however, noise levels scored significantly lower compared to the standard respirator group (Table 2 ). Employers in the UK have a legal responsibility to control substances hazardous to health in the workplace, and to prevent and adequately control their employees' exposure to those substances [13] . In the event of a chemical or radiological incident, casualties are a potential source of dangerous contamination to healthcare workers and should therefore be decontaminated before hospital admission. [8-11, 17, 18] but this is the first study to compare the use of modern respirators and powered respirators during advanced airway management procedures. Our main finding was that the use of videolaryngoscopy for difficult airway management proved to have certain advantages whilst wearing respiratory protection. Videolaryngoscopy is already widely advocated under normal circumstances [19] but also allows the anaesthetist to keep their head further away from the patient during airway management in COVID-19 patients [7, 20] . [10, 21] , their weight, bulk and connection to the corrugated breathing tube may impede the mobility of the wearer to a certain extent. It must also be noted that if the air supply to the powered respirator fails, then these devices will not provide any protection to the wearer. The user will then be exposed to contaminants in the ambient air, and increased levels of carbon dioxide due to rebreathing [12] . Therefore it is prudent to have charged, spare batteries readily available. Finally, we should note that our study took place in a controlled, simulated environment, and the participants were not required to physically exert themselves, and therefore we are unable to comment on Public health response to biological and chemical weapons Respiratory protection for medical first responders and receivers World Health Organization. Summary of probable SARS cases with onset of illness from 1 Guidance on infection prevention and control for COVID-19 World Health Organization: Coronavirus disease (COVID-19) technical guidance: Infection prevention and control Consensus guidelines for managing the airway in patients with COVID-19 A randomised crossover simulation study comparing the impact of chemical, biological, radiological or nuclear substance personal protection equipment on the performance of advanced life support interventions Respiratory protection during simulated emergency pediatric life support Comparison of powered and conventional air-purifying respirators during simulated resuscitation of CBRN victims Respiratory protection during high fidelity simulated resuscitation of casualties contaminated with chemical warfare agents -Respiratory protection for anaesthetists during resuscitation Respiratory protective devices -Recommendations for selection, use, care and maintenance -Guidance document. Technical Committee PH/4, Respiratory protection Respiratory protective equipment at work -A practical guide. HSG53. 4th edn Chemical warfare agentstoxicology and treatment Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults The Italian coronavirus disease 2019 outbreak: recommendations from clinical practice. Anaesthesia 2020. Epub ahead of print Comparison of six different intubation aids for use while wearing CBRN-PPE: a manikin study Insertion of six different supraglottic airway devices whilst wearing chemical, biological, radiation, nuclear-personal protective equipment: a manikin study Universal videolaryngoscopy: a structured approach to conversion to videolaryngoscopy for all intubations in an anaesthetic and intensive care department Videolaryngoscopy increases 'mouth-to-mouth' distance compared with direct laryngoscopy. Anaesthesia 2020. Epub ahead of print Powered air-purifying respirator use in healthcare: effects on thermal sensations and comfort Selection and use of respiratory protection by healthcare workers to protect from infectious diseases in hospital settings Speech intelligibility during respirator wear The Health and Safety at Work etc Act 1974. Ch37. London: The Stationery Office Management of health and safety at work. Management of Health and Safety at Work Regulations 1999. Approved Code of Practice and guidance L21 This study was prospectively registered by the UK Clinical Additional supporting information may be found online via the journal website.Appendix S1 Wearer comfort evaluation form.