Efficacy of surgical helmet systems for protection against COVID-19: a double-blinded randomised control study

This study assesses whether sterile surgical helmet systems (SSHS) provide surgeons with additional protection from aerosol pathogens alongside their traditional role protecting against splash. There has been debate on whether to use such systems in reopening elective orthopaedic surgery during the current COVID-19 pandemic environment.

Thirty-five participants were enrolled in a double-blinded randomised controlled study investigating efficacy of the Stryker Flyte Surgical Helmet (Stryker Corporation, Kalamazoo, MI, USA) as protection against respiratory droplets. Wearing the SSHS in a fit testing hood, subjects were randomised to nebulised saccharin solution or placebo. Twenty were allocated to the saccharin group with 15 to placebo. Positive sweet taste represented a failure of the test. Taste tests were performed with the helmet fan turned on and off.

SSHS did not prevent saccharin taste (p < 0.0001). Within the saccharin cohort, 40% recorded a positive taste with the fan on and 100% with the fan off. There was a statistically significant difference in mean time-to-taste saccharin (p = 0.049) comparing fan on (123.5 s) vs. off (62.6 s).

SSHS do not protect against aerosol particulate and therefore are not efficacious in protection against COVID-19. The fan system employed may even increase risk to the surgeon by drawing in particulates as well as delay recognition of intraoperative cues, such as exhaust from diathermy, that point to respirator mask leak.