Supplemental Oxygen During Surgery Reduces Risk of Wound Infection

Patients who received a higher concentration of supplemental oxygen during colorectal surgery had a significantly reduced risk of wound infection, according to a study in the Oct. 26, 2005 issue of JAMA.

Surgical wound infections prolong hospitalization by an average of 1 week and substantially increase the cost of care, according to background information in the article. These infections are possibly the most common serious complication of surgery and anesthesia. Supplemental oxygen during and after surgery has been variously reported to halve or double the risk of surgical wound infection.

F. Javier Belda, MD, PhD, of the Hospital Clínico Universitario de Valencia in Spain, and colleagues conducted a study to determine whether supplemental perioperative oxygen reduces the risk of wound infection. The double-blind, randomized controlled trial included 300 patients aged 18 to 80 years who underwent elective colorectal surgery in 14 Spanish hospitals from March 1, 2003, to Oct. 31, 2004. Baseline patient characteristics, anesthetic treatment, and potential confounding factors were recorded. Patients were randomly assigned to an oxygen/air mixture with a fraction (concentration) of inspired oxygen (Fio2) of 30 percent or 80 percent intraoperatively and for six hours after surgery.

A total of 143 patients received 30 percent perioperative oxygen and 148 received 80 percent perioperative oxygen. Surgical site infection (SSI) occurred in 35 patients (24.4 percent) administered 30 percent Fio2, and in 22 patients (14.9 percent) administered 80 percent Fio2.

We found that 80 percent supplemental oxygen reduced the risk of SSI by 39 percent. When controlling for multiple contributing factors, the reduction in SSI risk associated with 80 percent Fio2 was nearly 54 percent. Patients with infections had significantly longer hospital stays and delays to ambulation, the researchers write.

This result is consistent with most available in vitro data and 1 other appropriately designed randomized controlled trial. Supplemental oxygen appears to confer few risks to the patient, has little associated cost, and should be considered part of ongoing quality improvement activities related to surgical care, the authors conclude.

In an accompanying editorial, E. Patchen Dellinger, MD, of the University of Washington School of Medicine, Seattle, comments on the topic of preventing wound infection, a large number of other factors and interventions are known to influence risk for SSI in operative patients. For many of these interventions, there is essentially no controversy, and yet they are not being consistently delivered to patients. Recent surveys of actual practice in the United States show that proper choice of prophylactic antibiotic, timing of antibiotic delivery, avoidance of shaving the surgical site, keeping the patient warm in the operating department, and maintaining normoglycemia are not achieved in 10 percent to 55 percent of patients. Recent quality improvement SSI surveillance data from 1 hospital has demonstrated that when an SSI does occur, in more than 70 percent of the cases, known preventive measures, such as antibiotic delivery and maintenance of normothermia, were not achieved. A focused effort to change these conditions can result in a dramatic reduction in SSI.

 Surgeons and members of surgical teams should all be working in these areas until more definitive information about oxygen concentrations in the operating department becomes available. Surgeons should encourage the broader use of higher oxygen tensions for their patients undergoing major abdominal procedures and be more involved in quality improvement initiatives aimed at reducing SSI, Dellinger concludes.

References: JAMA.2005; 294:2035-2042 and  JAMA.2005; 294:2091-2092

Source: American Medical Association