Maintaining a clean environment is fundamental to patient safety during surgical procedures. Operating rooms must adhere to rigorous standards to minimize the risk of surgical site infections (SSIs), which can compromise patient outcomes. Achieving cleanliness requires a multilayered approach involving infrastructure, chemical agents, and methodical cleaning processes. Sterilization is not a single action but a continuous, integrated system that governs air quality, surface decontamination, and equipment handling.
Defining Asepsis and Sterilization
The terms used to describe cleanliness in a hospital setting are often confused, but they represent distinct levels of microbial control. Cleaning is the first step, involving the physical removal of foreign material, such as dust, soil, and organic matter, usually with a detergent and water solution. This action reduces microorganisms, preparing it for the next step.
Disinfection is the process of inactivating most pathogenic microorganisms, but it does not destroy all bacterial spores. High-level disinfection is used for items that contact mucous membranes or non-intact skin. Sterilization, by contrast, is an absolute term that describes the complete destruction of all microbial life, including highly resistant bacterial spores and viruses.
The goal for the surgical environment is asepsis, which is the absence of disease-producing microorganisms. While surgical instruments are sterilized in a separate department, the operating room itself cannot be continuously sterile in the absolute sense because human staff are present. Asepsis is maintained through protocols that prevent contamination from reaching the patient and the sterile field.
Maintaining the Sterile Environment: Air and Surface Preparation
Controlling the air quality is a foundational component of maintaining a clean surgical environment before a procedure even begins. Operating rooms rely on specialized Heating, Ventilation, and Air Conditioning (HVAC) systems to constantly filter and circulate the air. These systems provide at least 20 to 30 air changes per hour to dilute airborne contaminants.
A positive pressure differential is maintained inside the operating room relative to the surrounding corridors and support areas. This means air flows outward when a door is opened, preventing unfiltered air and contaminants from being drawn into the controlled surgical space. Air supplied to the room is passed through High-Efficiency Particulate Air (HEPA) filters, which are capable of trapping 99.97% of airborne particles measuring 0.3 micrometers or larger, including bacteria and mold spores.
Surface preparation is a methodical process undertaken before the first case of the day. A preliminary step, often called damp dusting, involves wiping down horizontal surfaces and equipment with a hospital-approved disinfectant or detergent before the sterile supplies are brought in. This removes any settled dust and debris that may have accumulated overnight. The establishment of the sterile field marks the creation of a contamination-free zone that must be protected throughout the procedure.
Terminal Cleaning: Decontaminating the Operating Room
The most intensive environmental decontamination occurs after a surgery is completed, known as terminal cleaning or turnover cleaning. Turnover cleaning takes place between surgical cases and focuses on the immediate area used by the patient and staff, while a more comprehensive terminal clean is performed at the end of the daily surgical schedule. The process must be systematic to ensure no area is missed and to prevent cross-contamination.
Cleaning staff work in a top-to-bottom and clean-to-dirty sequence, starting with high-level surfaces like surgical lights and ventilation grates and moving downward. The floors are always cleaned last to avoid splashing contaminants back onto previously disinfected surfaces. All horizontal surfaces, including the operating table, monitors, and anesthesia equipment, are wiped down using specific chemical agents.
Hospital-grade disinfectants are used for this process, including agents like quaternary ammonium compounds or accelerated hydrogen peroxide-based solutions. The effectiveness of these chemicals is dependent on the manufacturer’s specified contact time, which is the amount of time the surface must remain visibly wet for the agent to inactivate the target microorganisms. Proper disposal of biological waste is managed, with materials and sharps sealed in designated biohazardous waste containers before the room can be reset.
Quality Assurance and Regulatory Oversight
Hospitals rely on established standards to verify that cleaning procedures are effective and consistent. Visual inspection is insufficient, so facilities utilize testing methods to confirm that surfaces are adequately decontaminated. One common technique is Adenosine Triphosphate (ATP) testing, which measures the amount of residual organic matter remaining on a surface after cleaning.
A swab is taken from a surface and processed in a luminometer, which provides a reading in Relative Light Units (RLUs) within seconds. Since ATP is a molecule present in all living cells, a high RLU count indicates that organic residue, which can harbor pathogens, was not removed effectively. This rapid feedback allows cleaning staff to immediately re-clean any surfaces that fail to meet the established cleanliness threshold.
Environmental standards are provided by national organizations. The Centers for Disease Control and Prevention (CDC) and the Association of periOperative Registered Nurses (AORN) publish guidelines that hospitals use to develop their specific policies and procedures. These guidelines cover everything from air exchange rates to the proper use of disinfectants, ensuring a consistent level of environmental control is maintained across all surgical settings.