The operating room (OR) is a highly specialized environment where every parameter, including temperature, is strictly controlled. The distinctly cold air is not an accident but a deliberate environmental condition dictated by established protocols. This intentional reduction in ambient temperature manages the two primary risks of surgery: infection and operational failure. The cold maintains sterility, supports high-tech equipment, and ensures the surgical team performs optimally.
Controlling Infection and Sterility
Lowering the temperature is a long-standing measure that creates an environment less hospitable to microorganisms. Cooler temperatures actively inhibit the growth of bacteria and other pathogens on surfaces and in the air. This is a foundational component of infection control, prioritizing the minimization of bacterial activity.
The cold air also supports the OR’s sophisticated ventilation system. Operating rooms utilize high-efficiency particulate air (HEPA) filtration and laminar airflow to move clean air over the surgical field. Introducing cold air facilitates the high air exchange rate required by these systems, sometimes exceeding 20 air changes per hour.
A lower temperature also manages relative humidity, which must be kept within a specific range, often between 20% and 60%. Excessively high humidity promotes the growth of mold and mildew, potentially compromising sterile packaging and surgical materials. Maintaining a cool, dry environment preserves the integrity of sterile supplies and surgical drapes throughout the procedure.
Operational Requirements for Equipment and Staff
The low ambient temperature is a practical necessity for managing the heat generated by modern surgical technology. Operating rooms are filled with powerful, heat-producing devices, including high-intensity surgical lights and electronic monitoring screens. Maintaining a cool room prevents these machines from overheating, ensuring they function reliably throughout the procedure.
The cold also addresses the physiological needs of the surgical team, who wear multiple layers of protective gear. Staff wear sterile gowns, masks, gloves, and sometimes lead aprons, which can quickly lead to overheating and discomfort. A cool environment helps the staff remain alert and focused during lengthy operations, minimizing fatigue.
Keeping the room cool also prevents excessive perspiration from the staff. Sweat is a source of moisture and potential contaminants that risks compromising the sterile field. By reducing the risk of moisture breaching the sterile barriers of gowns and drapes, the cool temperature helps maintain sterility.
Active Patient Warming Strategies
While the room must be kept cool for sterility and operational reasons, the patient’s own body temperature must be carefully maintained. Unintended perioperative hypothermia, defined as a core body temperature below 96.8°F (36°C), is a serious complication. It can slow recovery, increase the risk of surgical site infection, and contribute to higher rates of bleeding. Therefore, the patient is actively kept warm throughout the procedure.
Specific warming strategies are implemented to counteract the cold environment and the effects of anesthesia, which impairs the body’s natural temperature regulation. The goal is to ensure the patient’s core temperature remains stable, typically at or near 98.6°F (37°C).
Methods used to maintain normothermia include:
- Forced-air warming blankets, which deliver heated air through a hose into a specialized blanket draped over the patient.
- Warmed intravenous (IV) fluids administered to prevent internal heat loss.
- Heated mattresses placed beneath the patient.
- Circulating water blankets placed beneath the patient.
These methods allow the OR to remain cool for safety and operational efficiency while simultaneously protecting the patient from the adverse effects of cold exposure.