Effect of upper versus lower body forced air warming in preventing perioperative hypothermia in patients undergoing lumbar spine surgeries: An observational study

Patients meeting the inclusion criteria will be selected, and informed consent will be obtained in the preoperative setting by the principal investigator. Baseline characteristics, including age, sex, BMI, ASA status, and will be recorded preoperatively. In the preoperative area, body temperature will be measured with a thermometer by the preoperative nurse, and also train the patients to use the thermal comfort scale. After transfer to the operating room, patients will be covered with a cotton blanket, and baseline vitals will be recorded. Following IV access, anaesthesia will be induced, and a nasopharyngeal probe will be inserted for core temperature monitoring. Standardized anaesthesia will be maintained with inhalational agents. After prone positioning, as per discretion of attending anesthesiologist either upper or lower body blanket is placed over the patient by the anaesthesia technician. In the upper warming group, the blanket will be placed above the T4 level, covering the back and both arms. In the lower warming group, the blanket will be positioned below the coccyx, covering both legs and the lower buttocks. Intraoperative warming will be provided via a forced-air warmer, with temperature readings recorded every 15 minutes by the PI. The warmer will be adjusted based on core temperature by the attending Anesthesiologist. If core temperature is less than 36.5 degree celsius then warming temperature is adjusted to 45 degree celsius, if core temperature is 36.5 to 37.5 degree celsius then warming temperature is adjusted to 40 degree celsius, and turned off if  greater than 37.5 degree celsius. At the end of surgery, the forced-air warmer will be removed and the patient will be placed in the supine position, the patient is fully covered with a cotton blanket. After reversal from anaesthesia, the nasopharyngeal probe and tracheal tube will be removed. The patient is transferred to the post-anaesthesia care unit (PACU). The thermometer will be used to monitor temperature every 10 minutes (up to 30 min) by the post anaesthesia care nurse. Patients will rate shivering intensity (0=no shivering,1= intermittent, low intensity ,2=moderate shivering,3=continuous intense shivering) and thermal comfort (0mm=coldest imaginable,50mm=pleasant,100mm=warmest imaginable) every 10 minutes following arrival in the post anaesthesia care unit (PACU). Before discharge, Patient will rate their satisfaction with perioperative temperature management on a 5-point Likert scale (0=very dissatisfied, 1=dissatisfied, 2=neutral, 3=satisfied, 4=very satisfied). Additional data on adverse effects, blood loss, transfusions, anaesthesia time, unwarmed period, and fluid volume will be observed and data is collected by the principal investigator.