A pilot study of coughing into the shirt to disrupt respiratory pathogen transmission

Abstract

Background: Scientific evidence is lacking for the respiratory etiquette maneuver of coughing into the elbow. This pilot study introduces and evaluates a novel maneuver " coughing into the shirt" comparing effectiveness of containing respiratory plumes to existing respiratory etiquette strategies.

Methods: In this open-bench, observational respiratory etiquette pilot study, five healthcare workers performed four respiratory etiquette maneuvers including: unobstructed, into the elbow, into a mask, and into the shirt. Observational data for the cough maximal plume area, an area calculation, were collected using slow-motion video recording. The various respiratory plume areas of the participants were compared to the unobstructed maneuver, assessing the percent reduction of the maximal plume area.

Results: All respiratory etiquette maneuvers significantly reduced the maximal plume area as compared to the unobstructed condition (F(3,12) = 18.56, P < 0.005). Comparing the maximal plume area of the unobstructed maneuver to the "into the shirt" maneuver, we found a 95.4% decrease for the "into the shirt" respiratory etiquette maneuver (P < 0.005). There was no statistically significant difference when comparing the obstructive maneuvers to each other. Additionally, the maximal plume area from the "into the shirt" maneuver was 35.75% less than the "into the elbow" maneuver (P = 0.15). Comparing the maximal plume area of the "into the shirt" maneuver to the "into the mask" maneuver, results were inconclusive, with an average difference of 2.24% (P = 0.66).

Conclusions: Coughing into the shirt may offer superior containment of the respiratory plume than coughing into the elbow. Larger studies are warranted to validate these findings and guide future public health recommendations.

Study design: Open bench, observational, cough etiquette pilot study comparing the into the shirt respiratory etiquette maneuver to other respiratory etiquette maneuvers.

Fig. 1

Cough maximal plume areas of the four respiratory etiquette maneuvers. Summary of cough maximal plume area (MPA) for anonymized participant 4 across all four respiratory etiquette maneuvers from the slow-motion videos. Each still image is annotated with the software detected maximal plume pixel boundary (pink outline). The unobstructed cough maximal plume area (MPA) is much bigger in area than the other maneuvers. The elbow maneuver produces a dense cloud of dust, whereas the mask and shirt maneuvers reduce the number of released particulates

Fig. 2

Summary cough maximal plume areas (MPA) for all participants and respiratory etiquette maneuvers, Summary of cough maximal plume area across anonymized participants from the slow-motion videos. Each video still image is annotated with the software-detected cough maximal plume area (MPA) across all four maneuvers. Some participant’s maneuvers did not result in software-detectable plumes notably in the into the shirt and mask maneuvers.

Fig. 3

Cough maximal plume area (MPA) pixel counts across all participants (1 through 5) and all maneuvers: unobstructed, elbow, mask, and shirt. The shirt maneuver generally shows cough MPA on par with the mask maneuver, except for Participant 4, which shows many white pixels that escape an untucked shirt or placement of the mouth relative to the shirt collar