Maintaining perioperative normothermia during laparoscopic and open urologic surgery

A multi-center study to predict the risk of intraoperative hypothermia in gynecological surgery patients using preoperative variables

OBJECTIVES

Hypothermia is highly common in patients undergoing gynecological surgeries under general anesthesia, so the length of hospitalization and even the risk of mortality are substantially increased. Our aim was to develop a simple and practical model to preoperatively identify gynecological surgery patients at risk of intraoperative hypothermia.

METHODS

In this retrospective study, we collected data from 802 patients who underwent gynecological surgery at three medical centers from June 2022 to August 2023. We further allocated the patients to a training group, an internal validation group, or an external validation group. The preliminary predictive factors for intraoperative hypothermia in gynecological patients were determined using the least absolute shrinkage and selection operator (LASSO) method. The final predictive factors were subsequently identified through multivariate logistic regression analysis, and a nomogram for predicting the occurrence of hypothermia was established.

RESULTS

A total of 802 patients were included, with 314 patients in the training cohort (mean age 48.5 ± 12.6 years), 130 patients in the internal validation cohort (mean age 49.9 ± 12.5 years), and 358 patients in the external validation cohort (mean age 47.6 ± 14.0 years). LASSO regression and multivariate logistic regression analyses indicated that body mass index, minimally invasive surgery, baseline heart rate, baseline body temperature, history of previous surgery, and aspartate aminotransferase level were associated with intraoperative hypothermia in gynecological surgery patients. This nomogram was constructed based on these six variables, with a C-index of 0.712 for the training cohort.

CONCLUSIONS

We established a practical predictive model that can be used to preoperatively predict the occurrence of hypothermia in gynecological surgery patients.

CLINICAL TRIAL REGISTRATION

chictr.org.cn, identifier ChiCTR2300071859.

Protocol-driven prevention of perioperative hypothermia in the pediatric neurosurgical population

OBJECTIVE

Perioperative hypothermia (PH) is a preventable, pathological, and iatrogenic state that has been shown to result in increased surgical blood loss, increased surgical site infections, increased hospital length of stay, and patient discomfort. Maintenance of normothermia is recommended by multiple surgical quality organizations; however, no group yet provides an ergonomic, evidence-based protocol to reduce PH for pediatric neurosurgery patients. The authors' aim was to evaluate the efficacy of a PH prevention protocol in the pediatric neurosurgery population.

METHODS

A prospective, nonrandomized study of 120 pediatric neurosurgery patients was performed. Thirty-eight patients received targeted warming interventions throughout their perioperative phases of care (warming group-WG). The remaining 82 patients received no extra warming care during their perioperative period (control group-CG). Patients were well matched for age, sex, and preparation time intraoperatively. Hypothermia was defined as < 36°C. The primary outcome of the study was maintenance of normothermia preoperatively, intraoperatively, and postoperatively.

RESULTS

WG patients were significantly warmer on arrival to the operating room (OR) and were 60% less likely to develop PH (p < 0.001). Preoperative forced air warmer use both reduced the risk of PH at time 0 intraoperatively and significantly reduced the risk of any PH intraoperatively (p < 0.001). All patients, regardless of group, experienced a drop in core temperature until a nadir occurred at 30 minutes intraoperatively for the WG and 45 minutes for the CG. At every time interval, from preoperatively to 120 minutes intraoperatively, CG patients were between 2 and 3 times more likely to experience PH (p < 0.001). All patients were warm on arrival to the postanesthesia care unit regardless of patient group.

CONCLUSIONS

Preoperative forced air warmer use significantly increases the average intraoperative time 0 temperature, helping to prevent a fall into PH at the intraoperative nadir. Intraoperatively, a strictly and consistently applied warming protocol made intraoperative hypothermia significantly less likely as well as less severe when it did occur. Implementation of a warming protocol necessitated only limited resources and an OR culture change, and was well tolerated by OR staff.

Unplanned perioperative hypothermia and agreement between oral, temporal artery, and bladder temperatures in adult major surgery patients

Accurate body core temperature measurement is essential in perioperative areas to quickly recognize and address abnormal temperatures. The purposes of this prospective, descriptive study were to accurately identify unplanned perioperative hypothermia (UPH) in 64 elective major surgery patients; to describe factors that increased the risk of UPH; to describe active/passive warming measures; to describe thermal comfort in patients with and without UPH; and to compare oral, temporal artery, and bladder temperatures. Based on bladder temperatures, 52% of the patients had UPH in the operating room (OR) and 42% on postanesthesia care unit (PACU) admission. The temporal artery thermometer did not detect any hypothermia. Descriptive data and Bland-Altman plots showed lack of agreement between the temporal artery thermometer readings and those of the oral and bladder thermometers. The patient's thermal comfort report did not accurately reflect hypothermia. Factors found to increase the risk of UPH included older age, BMI lower than 30, and OR ambient temperature lower than 68°F. All but one patient had active warming in the OR; active warming was infrequently used in the PACU. Based on our findings and findings in previous studies, we do not recommend using the temporal artery thermometer in perioperative areas. To prevent UPH, we recommend aggressive use of convective and conductive warming measures in perioperative areas and increasing OR ambient temperatures.