key: cord-0872270-62pnddks
authors: Zhang, Mingzhu; Zheng, Hui; Wang, Jingping
title: Strategy of using personal protective equipment during aerosol generating medical procedures with COVID-19
date: 2020-05-26
journal: J Clin Anesth
DOI: 10.1016/j.jclinane.2020.109911
sha: efbe69b3f21429d204582f3361b918ec5436918c
doc_id: 872270
cord_uid: 62pnddks

• Compared the effectiveness and cost-effectiveness between masks and respirators for the COVID-19 transmission; • Discussed the strategy to avoid severe nosocomial infection through aerosol-generating medical procedures; • Suggestions for healthcare workers to choose proper personal protective equipment.

The primary route for transmission of COVID-19 is via aerosolized droplets. Aerosol generating medical procedures (AGMPs) mainly include nebulizer treatment, bronchoscopy, non-invasive ventilation, tracheal intubation, and tracheostomy [1] . Standard eye protection, gown, and gloves are straightforward. Against respiratory transmission, recommendations for personal protective equipment (PPE) for health care workers (HCWs) are controversial. As such, the strategy of using PPE During AGMPs for COVID-19 Patients was discussed in this letter.

(Table1) Between N95 respirators and surgical masks in protection against laboratory-confirmed respiratory infection and influenza-like illness, there was insufficient evidence to determine a clinically significant difference showed by meta-analysis [3] . The N95 respirator is certified by National Institute for Occupational Safety and Health (NIOSH) to block at least 95 percent of 300-nm particles. Particles of 30 to 100 nm readily penetrate N95, while surgical masks admit 300-nm particles and do not provide substantial protection from aerosols of 500 nm [2] . Under laboratory condition, N95 respirators exhibit less filter penetration, less face-seal leakage, and less total inward leakage in comparison to surgical masks [3] . The spread of acute respiratory infections is a complicated process. Considering the low nosocomial infection rate of common influenza, larger and longer clinical trials are required to determine the clinical difference. For a sudden and severe pandemic like SARS or COVID-19, it is necessary to take into consideration J o u r n a l P r e -p r o o f Re-use of N95 respirators has been heatedly discussed. Hot air, boiling water, or steam sterilizations are proposed to provide satisfactory disinfection and preserved filtration performance, but better studies are needed to prove the safety and effectiveness. Physically, wearing a one-time-use surgical mask outside the N95 respirator, as a liquid barrier from the contamination of large droplets, may help keep the respirator relatively clean for reuse.

Reusable facial protective equipment, such as elastomer half-face respirators (EHFRs) and powered air-purifying respirators (PAPRs), is another desirable choice. EHFRs and PAPRs are not as satisfactory as N95 respirators in comfort and ease of verbal communication. EHFRs are not routinely used in hospitals, but they have the same assigned protection factor (APF) as N95 respirators and they are suitable replacements when N95 respirators are in short supply. In addition to a higher level of APF, PAPR provides a full coverage protection of the head and neck.

For medical staff familiar with the use of PAPR during SARS, it was proved that PAPRs are more protective than N95 respirators and are recommended for high-risk AGMPs [4] .

Covers for patients as the spreaders also help improve the protection efficiency. It is suggested patients wear surgical masks when being transferred or preparing for procedures.

Furthermore, barrier enclosures with/without negative pressure were designed for patients undergoing AGMPs. The negative pressure isolation hood covers the patient's head and neck.

There are two closed ports for the arms of HCWs to provide care. Laboratory simulations indicate effective confinement of aerosols to the hood. Such temporary barrier enclosures are 

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

Effect of Particle Size on the Performance of an N95 Filtering Facepiece Respirator and a Surgical Mask at Various Breathing Conditions

Effectiveness of N95 respirators versus surgical masks in protecting health care workers from acute respiratory infection: a systematic review and meta-analysis

User acceptance of reusable respirators in health care

Barrier Enclosure during