Anesthesiologist Mask Wearing and Surgical Site Infection Risk
The evidence indicates that anesthesiologists wearing face masks in the operating room does not significantly reduce surgical site infection rates, though masks should still be worn when performing sterile procedures or when there is risk of splash exposure.
Evidence Assessment
The available guidelines explicitly acknowledge the controversy surrounding mask use for SSI prevention. Multiple infection control guidelines from 2008 state that "the use of facemasks to decrease the incidence of postoperative wound infection has been questioned" and note that "the wearing of masks remains an area of contention" 1. These guidelines recommend masks primarily for:
- Protection against splash exposure to blood and body fluids
- When performing sterile procedures under full aseptic conditions
- Protection of the anesthesiologist from infectious respiratory droplets from patients
Notably, the 2020 World Journal of Emergency Surgery guideline on intraoperative SSI control does not mention face masks as a recommended intervention for SSI prevention 2.
Research Evidence
The clinical trial data supports the guideline ambiguity:
The highest quality randomized controlled trial enrolled 827 patients and found no significant difference in SSI rates between masked (11.5%) versus unmasked (9.0%) non-scrubbed operating room staff (OR 0.77,95% CI 0.49-1.21, p=0.151) 3
An earlier RCT of 3,088 patients found 4.7% infection rate with masks versus 3.5% without masks (not statistically significant, p>0.05) 4
A 2014 systematic review of four studies encompassing 6,006 patients found no difference in postoperative infection rates whether surgical masks were used or not 5
A 2014 review confirmed that while masks reduce bacterial counts in the OR, there is no evidence that masks reduce the prevalence of surgical site infection 6
Clinical Recommendation Algorithm
For routine anesthesia practice:
- Masks are not required for SSI prevention when the anesthesiologist is not performing sterile procedures
- Local hospital protocols should guide practice, as this remains institutionally variable 1
Masks ARE indicated when:
- Performing sterile procedures (central lines, epidurals, spinals) under full aseptic conditions 1
- Risk of splash exposure to blood, body fluids, or secretions exists 1
- Patient has infectious respiratory disease requiring droplet precautions 1
Important Caveats
Proper mask technique matters if worn:
- Do not pull down mask to speak
- Change if damp or contaminated
- Handle only by the ties
- Single-use only 1
What actually prevents SSI: The most recent 2023 JAMA review identifies evidence-based interventions that DO reduce SSI: avoiding razors for hair removal, chlorhexidine-alcohol skin prep, maintaining normothermia, perioperative glycemic control, appropriate antibiotic prophylaxis, and negative pressure wound therapy 7. Focus infection prevention efforts on these proven interventions rather than mask wearing by non-scrubbed personnel.
The evidence consistently shows that while masks may reduce bacterial dispersal theoretically, this does not translate into reduced SSI rates in clinical practice for non-scrubbed OR personnel including anesthesiologists 3, 4, 5, 6.