10 Minutes Prewarming and Warmed Intravenous Fluid on Core Temperature

Effect of 10 Minutes Prewarming and Warmed Intravenous Fluid on Core Temperature in Patients Undergoing Urologic Surgery Under General Anesthesia

Hypothermia occurs frequently during general anesthesia. This study is to evaluate the efficacy of 10 minutes of prewarming and warmed fluid during urologic surgery.

During general anesthesia, vasodilation distributes body heat and leads to hypothermia. Especially during urologic operation (transurethral resection of bladder and prostate), bladder irrigation worsens hypothermia. Hence, various methods are used to maintain core temperature during operation. Previous studies have demonstrated that prewarming of the patient is effective in maintaining core temperature perioperatively. However, more than 50% of patients who have applied prewarming for more than 30 minutes preoperatively are reported to fall in hypothermia. Hence, developing simple and effective method to prevent hypothermia is expected. Hence, the investigators planned to examine the effect of active warming (10 minutes of prewarming preoperatively and prewarmed intravenous fluid intraoperatively) on hypothermia in patients undergoing urologic operation under general anesthesia.

Warming group patients are applied prewarming with bair-hugger (43'C)(warm touch, COVIDIEN, full body blanket) for 10 minutes in the preanesthetic unit prior to induction of anesthesia. During operation, prewarmed intravenous fluid which was stored in the warming cabinet for more than 8 hours is connected and infused. Forced air blanket (warm touch, COVIDIEN, upper body blanket) with 38'C is applied for all patients during the operation.

No warming group patients are not applied prewarming devices. Intravenous fluid stored in room air is connected and infused during the operation. Forced air blanket (warm touch, COVIDIEN, upper body blanket) with 38'C is applied for all patients during the operation.

after completion of the operation, number of patients with hypothermia (<36'C) using esophageal stethoscope will be recorded.

shivering will be evaluated using 4 point shivering scale (0=none, 1=core and neck shivering, 2= upper extremity 3= whole body)

thermal comfort will be evaluated using thermal comfort scale ( 0= very cold, 5= fine, 10= very hot and uncomfortable)

Inclusion Criteria: patients undergoing urologic surgery(transurethral resection of bladder, prostate) Exclusion Criteria: moderate to severe cardiopulmonary, renal impairment thyroid disease any infection sign abnormal temperature prior to induction of general anesthesia (<36'C or >37.5'C) refusal to participate in the study unable to understand the study