A Prospective, Randomized, Controlled, Study Investigating Intraoperative Temperature and Postoperative Pain Course Following Gynaecological Laparoscopy

During the first 30 to 40 minutes of anaesthesia, a patient's temperature can drop to below 35.0°C. Reasons for this include loss of the behavioural response to cold and the impairment of thermoregulatory heat-preserving mechanisms under general or regional anaesthesia, anaesthesia-induced peripheral vasodilation, the use of cold dry insufflation gases. For these reasons, institutions employ a range of techniques to prevent hypothermia, including forced air warming (peri-operatively), use of warmed intravenous fluids, temperature monitoring and control of room temperature. Despite these interventions audits demonstrate that 20-56% of patients are hypothermic during the perioperative period. A factor often dismissed as a cause of peri-operative hypothermia during laparoscopic procedures is dry and cold insufflation gas. During laparoscopic procedures the abdomen is continuously insufflated with cold, dry CO2 resulting in desiccation and heat loss which consequently induces hypothermia in the patient. Clinical evidence suggests that the risk of hypothermia can be reduced using warm and humidified gas, as has been shown in animal models, in clinical trials and confirmed in a metaanalysis in humans. Only gas at body temperature and fully saturated with moisture will prevent loss of energy from the peritoneum surface - because it is physically not possible to evaporate fluids into a fully saturated gas. Therefore, the fluid layer will be maintained, minimizing energy loss from the body, decreasing the hypothermia induced by the evaporative losses in laparoscopic surgery and stabilizing the fibrinolytic activity of the peritoneum. The aim of this investigation is to assess the impact of forced air warming, warm humidified insufflation gas and the combination of the two on intraoperative temperature maintenance and the postoperative pain course as well as the fibrinolytic activity in peritoneal fluid following laparoscopic procedures (duration > 60 min) in a prospective, randomized, controlled, mono-centric study. Therefore 150 subjects will be randomized in 3 groups of 50 subjects each. First group will be treated with forced-air warming blanket (bair hugger). Second group will be treated with warmed, humidified insufflation via the F&P HumiGard™ Surgical Humidification System. Third group will be treated with both, warming blankets and warmed, humidified insufflation. The peri-operative temperature of patients might be higher in patients of the third group with the combination of both treatments. The investigators hypothesize that VAS scores for pain (especially shoulder pain), and MEDD usage will differ between groups. Wound infection incidence and time spent in PACU are also expected to differ. Fibrinolytic activity in the peritoneal fluid is expected to be higher in patients undergoing laparoscopic procedures with humidified gas insufflation, since the trauma to the peritoneum will be less.