By Scott Cathey, Senior Plumbing Designer
Reliable medical gas and vacuum systems are at the pinnacle of patient care. They provide life-supporting gases that are crucial for the proper treatment of patients in critical care areas. The ongoing operation and maintenance of these systems are vital to ensuring that they remain safe and dependable for patients, who rely on them for survival.
The National Fire Protection Association (NFPA) has a standard for electrical systems, as well as medical gas and vacuum systems, in healthcare facilities. NFPA 99 covers the performance, maintenance, installation, and testing of the medical gas system. NFPA defines facilities by a risk category of 1 through 4.
- Category 1: Failure of the piped gases and vacuum system would likely result in major injury or death to the patients, staff, or visitors.
- Category 2: Failure of the piped gases and vacuum systems would likely cause minor injury to patients, staff, or visitors.
- Category 3: Failure of the gas and vacuum supply would not likely cause minor injury to patients, staff, or visitors.
- Category 4: Failure of the gas and vacuum supply would have no impact on patients, staff, or visitors.
Most freestanding ambulatory surgical centers (ASCs) require either Category 1 or 2 because the administration of general anesthesia frequently occurs. In addition, the use of supplemental oxygen usually accompanies regional anesthesia and monitored anesthesia care.
Category 1 systems have multiple pumps to ensure continued flow of the medical gases and vacuum systems. Another difference between the four categories is the alarm features, which are more sensitive in the Category 1 system.
Guidelines have been set by the Facility Guidelines Institute (FGI) for the total number of outlets for medical gases and vacuum systems for ORs. State authorities having jurisdiction in some cases may have medical gas outlet requirements for ORs per that state. The Joint Commission has made recommendations as well. General recommendations include one oxygen and one vacuum station for minor surgery ORs, two oxygen and two vacuum stations for intermediate surgery ORs, and two oxygen and three vacuum stations for major surgery OR stations. Each station must have an adequate flow rate for proper delivery to the patient and adequate functioning of connected equipment. All medical piped gases must be identified by a color-coding system: oxygen (green), nitrous oxide (blue), nitrogen (black), medical air (yellow), and medical-surgical vacuum (white).
Medical gas and vacuum piping serving an OR can be delivered through multiple applications. Surgical ceiling columns or booms are the most common. Ceiling columns can be either rigid in design or retractable. When designing the facility, the ceiling columns should be placed at opposite ends of the OR table to provide easy access for the anesthesiologist. Extra electric outlets and receptacles can be placed on these columns for convenience. Medical booms that descend from the ceiling typically include medical gases and suction as well as electrical outlets. The placement of these booms may critically impact patients throughout the procedure, as well as safety for staff and patients. Typically, the anesthesia boom is placed behind and slightly to the right of the head of the OR bed, so the gas outlet and circuit are to the right of the anesthesiologist. With this configuration, neither the patient nor the staff need to walk through or around the boom to access the OR table or equipment.
The total medical gas consumption for the facility must be calculated. One must consider the procedures done at the facility, number of outlets, and the number of procedures to be performed monthly. In the acute care setting, consider oxygen utilization to be 1000 ft3 (28 m3) per bed per month. Any facility requiring more than 35,000 ft3 per month must have a bulk storage system of oxygen. Those requiring less than 35,000 ft3 per month can use a cylinder manifold system for oxygen supply.
The common source for nitrous oxide is the cylinder manifold system. Nitrous oxide should not be stored at temperatures lower than 20F or higher than 125F as the lack of heat for vaporization will occur, and it will be unable to maintain the line pressure. Medical compressed air can be delivered to the facility via a cylinder manifold or a medical air compressor system.
At the end of the medical gas installation the installer is to perform and document “installer performed testing” of distribution piping and components per NFPA 99. At the completion of the “installer performed testing” the system must be verified by a third-party verifier meeting the requirements of ASSE 6030, Professional Qualifications Standard for Medical Gas Systems Verifiers. The verifier test and documents that the system is clean and operating per NFPA 99 for patient use.