Cooling Vest May Reduce Heat Stress During Surgery

The investigators will propose a randomized cross-over trial using a uniform and strongly balanced 4-period design in which will include four operations for each surgeon. Surgeons will be randomized to 1 of 4 sequences: ABBA, BAAB, AABB or BBAA. The design is "uniform" in that each treatment appears the same number of times within each sequence (uniform within sequence) and if each treatment appears the same number of times within each period (uniform within each period). It is strongly balanced with respect to first-order carryover effects because each treatment precedes every other treatment, including itself, the same number of times

The subjects will be randomly assigned to use either the CoolSource™ cooling vest (worn between scrubs) and a conventional surgical gown for each of 4 surgeries. Sequence of treatments within the subjects will be randomized (ABBA, BAAB, AABB or BBAA), and determined using the PLAN procedure in SAS, such that each surgeon will wear vest and non-vest twice. The sequencing will not be shared with any study personnel. Allocation for each case will be concealed with a web-based system that will be accessed only shortly before surgery.

The investigators will target an ambient temperature of 21°C ± 1°C, and try to maintain the same temperature of each of the four study cases for each surgeon. The CoolSource vest holds six reusable cooling packs located bilaterally on the shoulders, angled flank along the base of the rib cage, and along each side of the spine, mid-back. The vest will be donned over hospital-issued scrubs after all temperature sensing devices have been applied and before surgical hand scrubbing. The subjects will wear the vest throughout surgery, and for a few additional minutes while postoperative assessments are made (details below).

The weight of the disposable cooling vest is 1 kg which is evenly distributed over both shoulders. The cooling packs have an insulated cover to reduce condensation or sweating while seated inside the vest pocket. The flexible frozen reusable cooling packs will be inserted into each of the six pockets and the vest belt will be tied to hold the cooling packs securely. The disposable cooling vests will be discarded after each case, and the cooling packs returned to a freezer.

Eligibility Criteria:
Inclusion Criteria:

* Surgeons who perform elective major orthopedic surgery such as total hip and knee arthroplasties scheduled for 90 to 150 minutes at the Cleveland Clinic Main Campus.
* Orthopedic surgeons ages of 25-65 years old, as body temperatures may be lower and less stable in the elderly (Waalen \& Buxbaum, 2011), who operate frequently enough to participate in four cross-over cases.
* Surgical helmet system is consistently worn for each of the surgeon's four cases, if used in the first case.

Exclusion Criteria:

* Surgical cases that require surgeons to sit on stools during the procedure, which may impact temperature and energy expenditure.
* - Surgeons who report having a recent illness within 24 hours prior to the surgery, symptoms producing a febrile condition;
* Surgeons who worked the previous evening.
* Surgeons who wear lead X-ray gowns.