36 patients American society of anesthesiology (ASA) physical status I,II and III undergoing general anesthesia for elective transurethral resection of the prostate (TUR-P) surgery will be included in the study. Patients will be randomized into two groups; first group(control group) and second group (forced-air warming). Resistive heating will start when patients are transferred to the operating room table; forced-air warming will start before preoperative 30 minute.

The primary aim of this study was to compare the effect of prewarming on perioperative hypothermia in elderly patients undergoing TURP under general anesthesia. In addition, we aimed to evaluate the effects of prewarming on hemodynamic variables, PACU output time, tremor, patient comfort and satisfaction. The investigators plan to enroll 36 patients in 2 groups. Body temperature will be measured at the core temperature, hemodynamic variables. Shivering will be graded by visual inspection. Thermal discomfort scale, patient satisfaction will be evaluated. The investigators hypothesize will decrease the forced air prewarming incidence of perioperative hypothermia.

Inclusion Criteria:

• Patients aged 50-85 years undergoing general anesthesia for TURP surgery
• ASA physical status I and III patients
• Body mass index between 15 and 36 kg/m2
• General anesthesia time is 30-90 minutes

Exclusion Criteria:

• without written consent,
• inadequate Turkish comprehension,
• known impaired thermoregulation or thyroid disorders,
• severe hypertension (systolic blood pressure [SBP]>180 mmHg or diastolic blood pressure [DBP] > 110 mmHg in the operating suite admission),
• an angiotensin-converting enzyme inhibitor/angiotensin II receptor antagonist on the day of surgery,
• secondary hypertension (e.g., renal artery stenosis, pheochromocytoma, Cushing's syndrome),
• vascular disease,
• poor cutaneous perfusion,
• serious skin lesions
• baseline temperature ≥37.5°C (degrees centigrade)