The purpose of this study is to determine whether a custom-made forced-air warming mattress can prevent heat loss in patients undergoing vascular surgery better than a circulating-water mattress

A reusable, custom-made forced-air warming mattress was made of a light to medium weight water resistant canvas, sewn like mattress with 2 arms placed underneath the patient. An open hole at proximal part of one arm was designed to attach with a hose of warm air delivery device. Small holes (2-3 mm2), 5 inches apart were punched on the upper surface of this mattress around the patient except for the area underneath the patient that the holes were 9 inches apart. The weight of the patient will obstruct the air flow and prevent direct blowing of warm air onto the underside of patients. There is a special appendage connected to the upper part of mattress which can connect warm air to cover the patient's chest. There is a special appendage connected to the upper part of mattress which can convect warm air to cover the patient's chest. The mattress is 97 inches x 97 inches, with 2 arms of 25 inches x 16 inches and a special appendage of 45 inches x 12 inches for covering the chest with warm air delivery. This size is proper for patient of 170 cm. height. In order to reuse it, the mattress can be washed, dried and sterilized by gas or autoclaved for more than 50 times. A sterile sheet well enhance the sterile environment of the operating field.

Inclusion Criteria:

Patients undergoing vascular surgery

Exclusion Criteria:

Preoperative fever