Maintaining normothermia may reduce risk of post-surgery infections

Issue: August 2007

Taking steps to ensure normothermia in patients after surgery should be routine for all hospitals to help reduce the risk of nosocomial infections, according to results of a new study.

The study, conducted by Anne Marie Pettis, RN, and her colleagues in the Infection Prevention team at Highland Hospital in Rochester, N.Y., found that normothermia was significantly associated with a reduced risk of infections. Furthermore, improvements in patients’ temperature control were more likely when anesthesiologists were asked to keep temperature reports for all patients.

Pettis presented the study at the 34th Annual Education Conference and International Meeting of the Association for Professionals in Infection Control, held recently in San Jose, Calif.

Temperature and infection

Pettis noted that previous studies have shown that hypothermia increased the risk of surgical site infections following colorectal surgery. Pettis and colleagues theorized that this would also be true for other types of surgery. With this in mind, Highland Hospital created the Surgical Site Infection Task Force. The goal of this task force was to improve the core temperature of all patients undergoing surgery to above 36 degrees Celsius (96.8 degrees Fahrenheit).

The task force identified a variety of possible factors that could potentially contribute to hypothermia in patients during or following surgery. These included cold laparoscopic gasses, the use of interventions in the operating room, patient’s age, type of surgery, anesthesia and anesthetist.

Median temperatures for 338 patients who had undergone various types of surgery were examined. Median temperatures were recorded during surgery and following surgery for all patients.

These records indicated that in the operating room, the median temperature for half of the patients was below 36 degrees Celsius; 25% were at or below 35.6 degrees Celsius.

In the post-operating stage, the median first temperature was 36.2 degrees Celsius; 25% of patients were at or below 35.7 degrees Celsius during this time.

Factors affecting temperature

Pettis said the researchers concluded that several of the potential factors were associated with a risk of hypothermia.

“Age was loosely correlated with operative temperature; however, the slope was flat over 50 years,” Pettis said. “Similarly, there was no definite association with case duration. Spinal anesthesia was associated with a much lower median temperature than general anesthesia. The median temperature also varied by type of surgery. Patients undergoing ear, nose and throat surgery had higher median temperatures; those undergoing prosthesis operations had lower median temperatures.”

The results also showed that the patient’s primary anesthetist was a significant predictor of the post-operative temperature. Patients whose anesthetists regularly monitored and recorded their temperatures were more likely to maintain optional temperature.

Pettis said her hospital has now implemented a system to better monitor patients for normothermia. “We determined that if our goal was to keep 90% to 95% of our patients warm during and immediately following surgery, we needed to aim for a median temperature of 37 degrees Celsius,” she said. “The monitoring system that we implemented should be helpful in assessing optimal surgical conditions to promote normothermia.”

For more information:

Pettis A. Temperature check for surgical site infection prevention. Presented at: the 34th Annual Education Conference & International Meeting of the Association for Professionals in Infection Control; June 24-27, 2007; San Jose, Calif.