BACKGROUND
Among the health risks associated with occupational exposure to anesthetic waste gases are an increased risk of both spontaneous abortion and congenital abnormalities among children born to women and wives of men who work with anesthetic gases.
Acute exposure to anesthetic waste gases has been associated with central nervous system effects such as headaches, irritability, nausea, and fatigue. Some test data indicates that impairments of perceptual, cognitive, and motor skills may result from exposure to concentrations of nitrous oxide as small as 50 PPM.
The American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit values for the anesthetic agents are 50 PPM for nitrous oxide, 50 PPM for halothane and 75 PPM for enflurane. The National Institute of Occupational Safety and Health (NIOSH), however, felt that no safe level of waste anesthetic gases could be defined because information on health effects is not completely definitive. The levels set by NIOSH are those that are attainable with proper anesthetic techniques, well maintained equipment, scavenging systems and ventilation. The recommended exposure limit (REL) for nitrous oxide is 25 PPM Time Weighted Average (TWA) during the period of anesthetic administration. The REL for the halogenated agents is 2 PPM, but NIOSH believes that if nitrous oxide concentrations are maintained below 25 PPM then the levels of the halogenated agents can be maintained below 0.5 PPM. The NIOSH document states that the "environmental limits should be regarded as the upper boundary and every effort should be made to maintain exposures as low as is technically feasible". OSHA currently does not have a standard for waste anesthetic gas exposure. However, OSHA has cited several hospitals for high anesthetic gas exposures under the General Duty Clause.

PURPOSE
The purpose of this policy is to outline the program elements of the UNC-CH Clinical Facilities and UNC Hospitals' Waste Anesthetic Gas Policy; to identify personnel who are exposed to waste anesthetic gases (WAGs); to categorize by procedure and/or task the concentration of waste anesthetic gases to which they are exposed; to evaluate techniques and ventilation used to reduce the airborne exposures; and to recommend corrective actions to reduce personnel exposures.

POLICY
Responding to the scientific literature indicating that there may be adverse health effects associated with exposure to waste anesthetic gases, UNC-CH Clinical Facilities and UNC Hospitals have established a program for the safe use of anesthetic gases that meets or exceeds the recommendations of occupational health advisory agencies (National Institute for Occupational Safety and Health and the American Society of Anesthesiologists) and complies with JCAHO accreditation criteria.

RESPONSIBILITIES

1. UNC-CH Environment, Health and Safety Office and UNC Hospitals’ Environmental Health and Safety Department - The UNC-CH Environment, Health and Safety Office and the UNC Hospitals’ Environmental Health and Safety Department will be responsible for sampling and maintaining records on all air sampling and shall prepare and forward a written report of the sampling results to the appropriate department manager for distribution to the affected employees.
2. UNC-CH Facilities Services and Medical Engineering Department - The Medical Engineering Department has the responsibility for preventative maintenance on anesthetic equipment to assure that the equipment is working properly so as not to harm the patient or expose the employees to high levels of anesthetic waste gases.
3. Anesthesiology Department/Dental Clinic and All Other Departments Using Anesthetic Agents - These departments have the responsibility for work practice control. Work practices may contribute to the majority of the anesthetic waste gases released into the scavenged operating room air. Therefore, it is essential to use proper anesthetic techniques.
   1. All departments using anesthetic gases shall be responsible for providing annual anesthetic gas safety training to their affected employees.
   2. All departments using anesthetic gases shall maintain records on training sessions including dates, topics, and attendees. Copies of these records shall be forwarded to the UNC-CH Environment, Health and Safety Office and the UNC Hospitals’ Department of Environmental Health and Safety.
   3. All departments using anesthetic gases shall encourage employees in the proper use of work practices designed to reduce ambient waste anesthetic gases during the anesthesia administration period.
4. Employee
   1. The employee shall be responsible for using anesthetic gases in a manner consistent with the design of the machine and the scavenging system used.
   2. The employee shall ask their supervisor for assistance in the event of problems or difficulties.

PROCEDURES

1. Scavenging systems
   Anesthesiologists and Certified Nurse Anesthetists are responsible for implementation and Medical Engineering is responsible for maintenance of equipment.
   1. Scavenging systems must be used with all anesthesia machines.
   2. Exhausts where anesthetic gases are vented must be separated from intakes in such a manner that prevents waste anesthetic gases from entering any ventilation intakes.
   3. Scavenging systems shall be checked for leakage semi-annually by Medical Engineering.
2. Anesthesia machines
   Medical Engineering and the Anesthesiology Technicians are responsible for maintaining the equipment.
   1. High-pressure systems shall be leak tested semi-annually by Medical Engineering.
   2. Low-pressure systems shall be tested with each use by the Anesthetist or Anesthesiologist.
3. Environmental monitoring
   UNC-CH Environment, Health and Safety Office and the UNC Hospitals’ Environmental Health and Safety Department are responsible for implementation.
   1. Sampling will be conducted on an annual basis in the areas where anesthetic gases are used by the UNC-CH Environment, Health and Safety Office and UNC Hospitals’ Environmental Health and Safety Department and whenever ventilation of anesthetic equipment or scavenging techniques are modified. Medical Engineering shall notify UNC-CH Environment, Health and Safety or UNC Hospitals’ Environmental Health and Safety to advise when ventilation of anesthetic equipment or scavenging techniques are modified.
      1. Personal sampling will be performed in the breathing zone of affected personnel during the anesthesia administration period using the Miran 1B. Areas where patients are recovering after anesthetic gas administration, such as the PACU, will be monitored as patients emit gases without the use of scavenging systems.
      2. Area sampling will be accomplished through infrared analysis using the Miran 1B.
   2. Results of monitoring will be forwarded to department managers for sharing with effected employees within thirty- (30) day of receipt of the results.
4. Ventilation
   1. Hospital minimum total air change rates will be strictly followed. NIOSH recommends at least 15 air exchanges per hour.
5. Product Labeling and Work Site Posting
   1. All areas where there is a potential exposure to anesthetic gases shall be posted with a sign that reads:
      (NAME OF AGENT)
      CAUTION: HARMFUL IF INHALED CONTINUOUSLY
      Use with adequate ventilation and/or scavenging equipment.
   2. Warning labels for anesthetic gases must not be removed from the product.
6. Occupational Health
   1. University Employees Occupational Health Clinic (UEOHC) and UNC Hospitals Occupational Health Service (OHS) provide counseling for employees, especially pregnant women, concerned about health effects related to occupational exposures including anesthetic gases. Employees desiring counseling should call UEOHC at 966-9119 or OHS at 966-4480 and make an appointment.
   2. Any employee who has problems or symptoms they feel are due to an occupational exposure to chemicals should fill out an incident report and be seen immediately in UEOHC or OHS.

IMPLEMENTATION
It is the responsibility of the Anesthesiology, Medical Engineering, UNC-CH Environment, Health and Safety, and UNC Hospitals’ Environmental Health and Safety Departments to implement this policy.
Reference: NIOSH Guidelines for Protecting the Safety and Health of Health Care Workers, U.S. Department of Health and Human Services. NIOSH publication No. 88-119, Government Printing Office, 1988.