22 The incidence of perioperative hypothermia and the effect of normothermia measures in the era of new surgical approaches

Abstract Aim Although disruptive scientific evidence fueled the inclusion of perioperative normothermia measures in to the bundles to prevent hypothermia, data on the specific tools to adequate implement normothermia measures in patients at risk are lacking. Also, is unknown how the evolving new surgical devices devoted to facilitate both less invasive and precision surgical techniques influence on the efficacy of classical normothermia measures. Pragmatic prospective observational study was designed to clarify which surgical patients are at risk for perioperative hypothermia and the efficacy of the available physical normothermia measures in the era of evolving new surgical devices and techniques. Methods The study was approved by the Ethic Committee of the center. Adults patients submitted to major surgical procedures were included. Perioperative continuous core temperature (CT) monitoring has been assessed with the SpotOn system. Conventional normothermia measures applied during surgical procedures were registered. Warmed Body Surface Area (WBSA) Score was constructed following the rule of nine (burned patients). Surgical procedures were classified depending of the anatomical compartment involved: Articular, Head and Neck, Organ-Cavity and Trunk. Also, Organ-cavity surgical procedures were further classified depending on the type of surgical access: Open, laparoscopic and robotic. Variables were summarized as mean ± SD or 95% c.i. or as median and interquartile range, when appropriate. Differences in AUC below 35.5° among different anatomical compartment surgical procedures and depending on the operative access (open, laparoscopic and robotic), were analyzed by employing the non-parametric Kruskall Wallis test. Differences in mean CT throughout the time points among groups were tested using one-way analysis of variance. Multiple comparisons were performed using Scheffé’s test. We considered differences significant at P < 0.05. Results Eighty-nine patients were included for the final analysis, 51.7% (41.4 to 62) women with mean age of 62.9 (59.8 to 66.0) years and ASA II in 55.7% (49.4 to 69.7) of patients. Warmed forced air blanket was the most normothermia measure employed (100%, 84.6%; 91.7% and 100% in Organ-cavity, articular, Head and Neck and Trunk surgeries, respectively). Compared to open procedures, WBSA was significantly lower in both laparoscopic and robotic surgical procedures (54% versus 27% and 18%, respectively, P < 0.001). CT was assessed during each surgical procedure at the specific time points. CT dropped early on after anesthesia induction. Organ-Cavity surgical procedures persistently demonstrated significant lower CT values during the overall procedure. Head/Neck dropped sharply showing early recovery and finally achieving hyperthermia values. Also Time-weighted average CT was significantly lower in Organ/Cavity surgical procedures. We further explore CT variables in Organ-cavity group of patients, taking in to the account the technique of surgical access. Regarding CT relevant variables, we observed that endoscopic procedures showed lower mean CT values overall (non-significant), higher AUC below the threshold (35.5°C) (non-significant), a higher percentage of patients 35.5°C (significant), mainly in robotic access group Conclusion Perioperative hypothermia is not an homogenous adverse event. Despite endorsement of conventional normothermia measures, patients submitted to organ-cavity surgical procedures are at risk for perioperative hypothermia. New and adapted normothermia measures for endoscopic and robotic based surgery are urgent needed.