Effect of Prewarming During Induction of General Anesthesia Combined With Warmed Intravenous Fluid on Core Temperature.

Hypothermia is of continuous issue in patients undergoing general anesthesia. During urologic operation (transurethral resection of bladder and prostate), bladder irrigation worsens hypothermia. Hence, various methods including prewarming of the patient are used to maintain core temperature during operation.

Prewarming is found to be effective in maintaining core temperature perioperatively by increasing peripheral tissue heat content. However, applying more than 30 minutes of prewarming may be impractical as a clinical routine practice. Hence, developing simple and effective method to prevent hypothermia is expected.

Here, the investigators planned to examine the effect of active warming (10 minutes of warming during induction of general anesthesia and prewarmed intravenous fluid intraoperatively) on hypothermia in patients undergoing urologic operation under general anesthesia.

• warming during induction of anesthesia (Procedure): Warming group patients are applied air-forced warming device (bair-hugger 43'C) with blanket (warm touch, COVIDIEN, full body blanket) during induction of anesthesia in the operation room.
• Prewarmed intravenous fluid administration (Procedure): Prewarmed intravenous fluid is connected.

Primary outcomes

• incidence of hypothermia at the end of the operation [approximately 1-2hours after induction (at the end of operation)]: number of patients with hypothermia (<36'C) using esophageal stethoscope will be recorded.

Secondary outcomes

• change in temperature drop before and end of operation [on arrival at the OR upto 1-2hours after induction (at the end of the operation)]: change in core temperature will be observed
• thermal comfort [upto 1hour after end of the operation (at discharge of postanesthesia care unit)]: thermal comfort scale ( 0= very cold, 5= fine, 10= very hot and uncomfortable) will be used.
• incidence of shivering [upto 1 hour after end of the operation (on arrival at the postanesthesia care unit)]: 4 point shivering scale (0=none, 1=core and neck shivering, 2= upper extremity 3= whole body) will be used.

Sex: All, ages: 20 Years to 90 Years, accepts healthy volunteers

Inclusion Criteria:

* patients undergoing urologic surgery(transurethral resection of bladder, prostate)

Exclusion Criteria:

* moderate to severe cardiopulmonary, renal impairment
* previous 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

• In-Jung Jun, MD, PhD, Principal investigator, assistant professor