The Effect of Operating Room Size on Orthopaedic Surgical Site Infection Rates

Role of Operating Room Size on Air Quality in Primary Total Hip Arthroplasty

BACKGROUND

Airborne biologic particles (ABPs) can be measured intraoperatively to evaluate operating room (OR) sterility. Our study examines the role of OR size on air quality and ABP count in primary total hip arthroplasty (THA).

METHODS

We analyzed primary THA procedures done within 2 ORs measuring 278 ft² and 501 ft² at a single academic institution from April 2019 to June 2020. Temperature, humidity, and ABP count per minute were recorded with a particle counter intraoperatively and cross-referenced with surgical data from the electronic health records using procedure start and end times. Descriptive statistics were used to evaluate differences in variables. P-values were calculated using t-test and chi-squared test.

RESULTS

A total of 116 primary THA cases were included: 18 (15.5%) in the "small" OR and 98 (84.5%) in the "large" OR. Between-group comparisons revealed significant differences in temperature (small OR: 20.3 ± 1.23 C versus large OR: 19.1 ± 0.85 C, P < .0001) and relative humidity (small OR: 41.1 ± 7.24 versus large OR: 46.9 ± 7.56, P < .001). Significant percent decreases in ABP rates for particles measuring 2.5 um (-125.0%, P = .0032), 5.0 um (-245.0%, P = .00078), and 10.0 um (-413.9%, P = .0021) were found in the large OR. Average time spent in the OR was significantly longer in the large OR (174 ± 33 minutes) compared to the small OR (151 ± 14 minutes) (P = .00083).

CONCLUSION

Temperature and humidity differences and significantly lower ABP counts were found in the large compared to the small OR despite longer average time spent in the large OR, suggesting the filtration system encounters less particle burden in larger rooms. Further research is needed to determine the impact this may have on infection rates.

The Association of Immediate-Use Steam Sterilization with the Incidence of Orthopaedic Surgical Site Infections: A Propensity Score-Matched Cohort Study

BACKGROUND

Immediate-use steam sterilization (IUSS), formerly termed "flash" sterilization, has been historically used to sterilize surgical instruments in emergency situations. Strict guidelines deter its use, as IUSS has been theorized to increase the risk of surgical site infections (SSIs), leading to increased health-care costs and poor patient outcomes. We sought to examine the association between the use of IUSS and the rate of orthopaedic SSIs.

METHODS

The cases of 70,600 patients who underwent orthopaedic surgery-total knee or hip arthroplasty, laminectomy, or spinal fusion-from January 2014 to December 2020, were retrospectively reviewed for IUSS use. Of this group, 3,526 patients had had IUSS used during surgery. A propensity score-matched (PSM) analysis was conducted to account for known predictors of SSIs and included a total of 7,052 patients. The risk difference (RD), relative risk (RR), odds ratio (OR), and McNemar test compared the SSI risk for patients whose procedure had included the use of IUSS and those whose procedure had not included IUSS.

RESULTS

After propensity score matching, 111 (1.57%) of the 7,052 matched patients developed an SSI. Of the 111 patients, 61 (54.95%) were in the IUSS group and 50 (45.05%) were in the non-IUSS group. The estimated probability for developing an SSI was 1.42% for the patients in the non-IUSS group versus 1.73% for the patients in the IUSS group (RR = 0.82 [95% confidence interval (CI)]: 0.57 to 1.19], RD = -0.3% [95% CI: -0.9% to 0.27%]).There was no evidence that the proportion of SSI was greater in the IUSS group (McNemar test, p > 0.29).

CONCLUSIONS

SSI rates were not significantly different between IUSS and non-IUSS patients undergoing orthopaedic surgery. Future prospective studies are warranted to further explore the utility of IUSS during orthopaedic procedures.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.