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Protection of the surgeon

An increasingly prevalent belief, in favour of mask usage, is the idea that they also confer some degree of protection to the operating staff from patient-derived infectious material.18 Most obviously, they can act as a physical barrier against blood and bodily fluid splashes during surgery. One prospective study revealed that facemasks prevented blood/bodily fluid splashes that would have otherwise contaminated the surgeon’s face in 24% of procedures.19 The incidence of blood/bodily fluid splashes varies substantially between settings and between individuals. The risk is modified by the role of surgical staff (lead surgeons are at higher risk than first assistants, who in turn have a higher risk than scrub nurses), by surgical specialty as well as by surgical technique.19,20 The frequency of blood/bodily fluid splashed has been reported to be as high as 62.5% in lead surgeons performing Caesarean section.20

Despite clear evidence that facemasks act to protect the theatre staff from macroscopic facial contamination, there are studies to suggest that they fail to protect surgeons from potentially hazardous sub-micrometre contaminants.21 This corresponds roughly to the size range of infectious bacteria while viruses are even smaller. Therefore, the protection that masks confer in the form of macroscopic facial contamination may not necessarily extend towards any microscopic infectious agents present within that contamination.

Proponents of the surgical facemask may argue that even if they fail to completely negate the risks of infection they are likely to reduce exposure in a dose-dependent manner. While this field has not been extensively investigated, preliminary work suggests that facemasks fail to confer any degree of protection from infection due to streptococcal and staphylococcal bacterial species22 or hepatitis B virus.23 Furthermore, a facemask splash may promote a false sense of security, as surgeons may be less likely to report these as an occupational exposure to bodily fluid compared to frank facial contamination.