Face masks reduce disease transmission by protecting the wearer from inhaled pathogens and reducing the emission of infectious aerosols. Although methods quantifying efficiency for wearer protection are established, current methods for assessing face mask containment efficiency rely on measurement of a low concentration of aerosols emitted from an infected or noninfected individual.

A small port enabled the introduction of 0.05 µm sodium chloride particles at a constant rate behind the mask worn by a study participant. A condensation particle counter monitored ambient particle numbers 60 cm in front of the participant over 3-minute periods of rest, speaking, and coughing. The containment efficiency (%) for each mask and procedure was calculated as follows: 100 × (1 − average ambient concentration with face covering worn/average ambient concentration with a sham face covering in place). The protection efficiency (%) was also measured using previously published methods. The probability of transmission (%) from infected to uninfected (a function of both the containment efficiency and the protection efficiency) was calculated as follows: {1 − (containment efficiency/100)}×{1 − (protection efficiency/100)}×100.

The average containment efficiencies for each mask over all procedures and repeated measures were 94.6%, 60.9%, 38.8%, and 43.2%, respectively, for the N95 mask, the KN95 mask, the procedure face mask, and the gaiter. The corresponding protection efficiencies for each mask were 99.0%, 63.7%, 45.3%, and 24.2%, respectively. For example, the transmission probability for 1 infected and 1 uninfected individual in close proximity was ∼14.2% for KN95 masks, compared to 36%–39% when only 1 individual wore a KN95 mask.

Overall, we detected a good correlation between the protection and containment that a face covering afforded to a wearer.

Personal protective equipment (PPE) is worn by prehospital providers (PHPs) for protection from hazardous exposures. Evidence regarding the ability of PHPs to perform resuscitation procedures has been described in adult but not pediatric models. This study examined the effects of PPE on the ability of PHPs to perform resuscitation procedures on pediatric patients.

This prospective study was conducted at a US simulation center. Paramedics wore normal attire at the baseline session and donned full Level B PPE for the second session. During each session, they performed timed sets of psychomotor tasks simulating clinical care of a critically ill pediatric patient. The difference in time to completion between baseline and PPE sessions per task was examined using Wilcoxon signed-rank tests.

A total of 50 paramedics completed both sessions. Median times for task completion at the PPE sessions increased significantly from baseline for several procedures: tracheal intubation (+4.5 s; P = 0.01), automated external defibrillator (AED) placement (+9.5 s; P = 0.01), intraosseous line insertion (+7 s; P < 0.0001), tourniquet (+8.5 s; P < 0.0001), intramuscular injection (+21-23 s, P < 0.0001), and pulse oximetry (+4 s; P < 0.0001). There was no significant increase in completion time for bag-mask ventilation or autoinjector use.

PPE did not have a significant impact on PHPs performing critical tasks while caring for a pediatric patient with a highly infectious or chemical exposure. This information may guide PHPs faced with the situation of resuscitating children while wearing Level B PPE.