Tissue oxygen saturation, measured by near-infrared spectroscopy, and its relationship to surgical-site infections

Background Surgical-site infections (SSIs) are common after major abdominal and groin bypass surgery. Tissue oxygen tension has been shown to predict these infections accurately. This study assessed whether a non-invasive measurement of tissue oxygenation, tissue oxygen saturation as measured by spectrophotometry, was as accurate. Methods Fifty-nine patients having major abdominal or groin bypass surgery had tissue oxygen saturation measured by near-infrared spectrophotometry at the incision site and in the arm before operation, and at 12, 24 and 48 h after surgery. Masked outcome assessments for SSI were made at 7 and 30 days after operation. Results In this retrospective analysis, 17 patients (29 per cent) developed an SSI. At 12 h after operation there was a significant difference in tissue oxygen saturation at the surgical site between patients who developed an SSI and those who did not (mean(s.d.) 43·4(18·1) versus 55·8(22·0) per cent; P = 0·032). These oxygen saturation readings were found to be more specific and sensitive in predicting SSIs than the National Nosocomial Infection Surveillance system. Discussion There is a difference in postoperative surgical-site oxygen saturation between patients who subsequently develop SSIs and those who do not. Prediction of SSIs provides opportunities for intervention and prevention.