key: cord-0925516-sd27o8dd authors: Wong, Patrick; Kim Ong, Sharon Gek; Lim, Wan Yen title: COVID-19 and cardiopulmonary resuscitation: the recommended N95 mask may not be adequate date: 2020-05-18 journal: Br J Anaesth DOI: 10.1016/j.bja.2020.05.008 sha: 223b40cebc4f37d4c1518d20e3bef6f096c825be doc_id: 925516 cord_uid: sd27o8dd nan Editor -The COVID-19 pandemic due to the SARS-CoV-2 virus is primarily spread by droplet (and perhaps aerosol) and contact transmission, with a fatality rate of about 3.1%. 1 At in-hospital 'code blue' activations for cardiac arrest, anaesthetists may be called to assist in airway management and cardiopulmonary resuscitation (CPR) where various potentially aerosol-generating procedures are performed e.g. face mask ventilation, intubation and chest compression. [1] [2] The European Resuscitation Council recommends that rescuers don personal protective equipment (PPE) before starting chest compressions even if this results in a brief delay. 1 The minimum recommended PPE is a FFP3 respirator mask (FFP2 or N95 if FFP3 is unavailable), eye and face protection, long-sleeved impermeable gown, and gloves. 1 Although delays are associated with increased morbidity and mortality, "safety of staff is paramount" 1 as CPR associated bacterial and viral infection of healthcare workers has been reported. 3 The healthcare worker's duty of care to patients is associated with significant risks of infection and even death to themselves. The duty of care also extends to preventing onward transmission to other patients, their colleagues, their relatives and the wider community. 1 The appropriate use of PPE is therefore key. In a review of previous virus outbreaks and pandemics, most guidelines recommended use of an N95 mask. 4 The N95 mask is a filtering, negative pressure facepiece respirator, and its performance is highly dependent on a tight face seal. 2 However, there are three drawbacks with the N95 mask. First, it is inferior to an FFP3 mask which is the first line recommendation: the minimum filtration efficiencies of aerosol test particles are 95% and 99%, respectively. 2 Second, prior N95 mask fit testing does not ensure maintenance of a tight face seal. 2 Recent studies show that N95 mask shape and vigorous movements may decrease its performance and ability to protect healthcare workers during CPR. In one simulation study, 61% of participants who fully passed N95 mask fit-testing (which included head nodding and bending) 3 failed at least one of three sessions of chest compression. Overall, 18% of participants experienced mask failures such as strap slipping. 3 In another simulation study, fold type N95 masks performed better than cup and valve-type N95 masks. 5 Adequate protection rates at baseline were 100%, 73.6% and 87.5%, respectively; and during chest compressions were 93.2%, 44.9%, 59.5%, respectively. 5 This may have been related to the fixed shape of and increased leakage with the cup and valve-type N95 masks. 5 During pandemic planning where there is a risk of respirator supply depletion, there may be recommendations for N95 mask extended use ("wearing the same N95 respirator for repeated close contact encounters with several patients, without removing the respirator between patient encounters") and reuse ("by the same person with adequate reprocessing/decontamination). 6 However, the risk associated with extended use or reuse are: self-inoculation or transmission to others; contravening manufacturer's "for single use only" instructions; decreased functionality; and, additional discomfort. 6 Better protection during CPR may be conferred with a powered air-purifying respirator (PAPR). PAPRs provide 2.5-100 times greater protection than N95 masks as indicated by their respective assigned protection factors. 2 The latter denotes the factor by which a respirator reduces aerosol contaminants in the ambient air, with a higher value indicating greater protection. 2 A recent meta-analysis concluded that use of a PAPR with a coverall may protect against the risk of contamination better than a N95 mask and gown [risk ratio (RR) 0.27]. 7 Donning was however more difficult (non-compliance: RR 7.5) and was time-consuming in a recent simulation study, 8 which could have a negative impact on outcome. 7 PAPRs may also offer greater protection than officially assigned. 9 One study showed that a loose-fitting PAPR provided sufficient respiratory protection, with no disconnection of equipment or mechanical failures during chest compression. 10 However, over-breathing with inspiratory flow rates exceeding the PAPR flow rate can occur. 8 The resulting loss of positive pressure within the PAPR entrains air, but aerosol penetration remains low. 9 PAPRs are also more complex, require significant training, less readily available, and are associated with higher non-compliance and longer donning/doffing times that delay commencing CPR. 7, 8, 11 Both N95 masks and some PAPRs do not provide "complete coverage of head and facial skin" as recommended for management of COVID-19 patients. 12 Greater coverage, however, is associated with increased difficulty during donning/doffing, discomfort and contamination. 7 A comparison between PAPRs and the N95 mask is presented in Table 1 . 5 When PAPRs are not available, other PPE variations have been reported. These range from a full body suit (which provides a high level of droplet protection but low airborne reduction factors) with an N95 mask, 13 to elastomeric respirators. 2 Mechanical chest compression devices may also reduce infection risk by minimizing the number of rescuers and circumventing the exposure risk from a shifting N95 mask during manual chest compressions. 1 Although an N95 mask is the minimum respirator recommended for CPR, recent evidence shows that it may not function well during CPR, and that PAPRs may be superior at decreasing contamination. Healthcare workers should be aware of the clinical, resource and logistical limitations of both N95 masks and PAPRs. 8 European Resuscitation Council COVID-19 Guidelines Personal Protective Equipment for Care of Pandemic Influenza Patients: A Training Workshop for the Powered Air Purifying Respirator N95 filtering facepiece respirators do not reliably afford respiratory protection during chest compression: A simulation study Availability, consistency and evidence-base of policies and guidelines on the use of mask and respirator to protect hospital health care workers: a global analysis Comparing the protective performances of 3 types of N95 filtering facepiece respirators during chest compressions: A randomized simulation study CDC -Recommended Guidance for Extended Use and Limited Reuse of N95 Filtering Facepiece Respirators in Healthcare Settings -NIOSH Workplace Safety and Health Topic The authors declare no conflicts of interest.