Operating rooms (ORs) are controlled environments designed for patient safety during surgical procedures. The distinct chill in the air is not arbitrary; it is a carefully managed parameter serving multiple, interconnected functions. This low temperature is a deliberate result of engineering and clinical necessity, primarily driven by infection control, the physical demands on the surgical team, and compliance with strict environmental regulations.
Maintaining Sterile Conditions
The low temperature is directly linked to the sophisticated air handling system necessary for infection prevention. Operating rooms receive a high volume of highly filtered air, exchanged at a rate of 20 to 25 times per hour. This rapid exchange constantly dilutes and removes airborne contaminants from the surgical field.
The cool air prevents the formation of warm convection currents. Warm air rising from heat sources, like surgical lights and staff bodies, can carry skin particles and bacteria, potentially contaminating the surgical site. The cooler ambient temperature stabilizes the airflow, ensuring contaminants settle quickly toward the floor for removal by the ventilation system.
A temperature range between 68°F and 73°F is optimal because it inhibits the proliferation and growth rate of airborne microorganisms. Controlling the relative humidity between 20% and 60% is also paramount for sterility. High humidity promotes microbial growth, while very low humidity can increase static electricity that may damage equipment.
Optimizing Surgeon Performance
The rigorous requirements of surgical attire necessitate a cool environment for the comfort and focus of the operating team. Surgeons, nurses, and technicians wear multiple layers of fluid-resistant and impermeable apparel, including gowns, gloves, and masks, which effectively traps body heat.
Lengthy, physically demanding procedures cause surgical personnel to generate significant internal heat. Without a cool ambient temperature, staff would quickly overheat, leading to fatigue, distraction, and excessive perspiration. Perspiration is a major concern because it compromises the sterile field by increasing the shedding of skin particles and microorganisms through the gown material.
A cooler room maintains the concentration and dexterity of the surgical team by reducing the physiological stress of working under intense lighting and heavy protective layers. The temperature balances the need for a clean environment with maintaining peak human performance.
Regulatory Standards for Temperature Control
Specific administrative and engineering mandates enforce the narrow temperature range found in operating rooms. Organizations like the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) establish strict parameters. ASHRAE Standard 170 recommends maintaining temperatures between 68°F and 75°F (20°C and 24°C), depending on the specific procedure.
This narrow band is determined by biological concerns and the requirements of specialized equipment. Sophisticated electronic devices used in surgery, such as monitoring and imaging systems, are sensitive to heat and humidity fluctuations. Maintaining a controlled climate prevents equipment malfunction and ensures the reliability of sterile supplies.
Managing Patient Hypothermia Risk
Although the cold environment is necessary for sterility and staff performance, it introduces a significant risk for the patient lying exposed and immobile. General anesthesia impairs the body’s natural ability to regulate temperature, causing rapid heat redistribution from the core. This can lead to perioperative hypothermia, defined as a core body temperature below 96.8°F (36°C).
Hypothermia is a serious complication that increases the risk of surgical site infection, slows medication metabolism, and delays recovery. To counteract the cold room, surgical teams employ active warming measures. These methods include forced-air warming blankets placed over the patient, and warmed intravenous fluids administered throughout the procedure.
Patients are also placed on heated mattresses or pads to minimize heat loss from the operating table. The use of these warming devices ensures the patient’s core temperature remains stable, mitigating the risks associated with the necessary cool environment.