Frequently Asked Questions
All work with anesthetic gases must be performed with either dedicated exhaust (e.g., fume hood, local exhaust ventilation) and/or a scavenging system to prevent exposure. Exposures can occur when handling the gases or liquids, leakage from equipment, from the patient or animal breathing circuit during delivery of anesthesia, or as exhaled by the patient or research animal (e.g., during recovery).
Workers may be exposed to waste anesthetic gases when:
Clinical/Dental:
- Leaks occur in the anesthetic breathing machine, breathing system, hoses, and connections.
- Anesthetic gas seeps over the lip of the patient’s mask or from the tracheal tubing or coupling
- Patient is mouth-breathing or talking during dental work
Animal:
- Inducing anesthesia using liquid anesthetics and induction boxes
- Opening induction boxes
- Charcoal canister in scavenging system is saturated
All applications:
- Anesthetic gases escape during connection of the anesthesia system or scavenging system
- Filling vaporizers
- Leaks occur between subject and facemask/nose cone
- Liquid anesthetics spill
- Anesthesia system is flushed or purged at end of a procedure
- Ineffective or poor ventilation system or gas scavenging system
Clinical workers who may be exposed to anesthetic gases include:
- Anesthesiologists
- Nurse anesthetists
- Dentists
- Dental assistants
- Dental hygienists
- Operating-room nurses
- Operating-room technicians
- Other operating-room personnel
- Recovery-room nurses
- Other recovery-room personnel
- Surgeons
In animal research environments, the following workers may be exposed to anesthetic gases:
- Research staff
- Veterinary staff
- Animal care technicians
Most anesthetic gases have high odor thresholds. This means that anesthetic gases cannot be detected by their odor until concentrations are very high. For example, halothane cannot be detected by 50% of the general population until the concentration is more than 125 times the National Institute for Occupational Safety and Health (NIOSH) recommended exposure limit. Therefore, workers should never rely on odor as a warning of potential exposure to anesthetic gases.
Specific anesthetic gases and liquids used at UW are listed below. At room temperature, nitrous oxide is a gas. Mixed with oxygen, it is commonly used for sedation and pain relief in dentistry. The halogenated anesthetic agents are volatile liquids that are vaporized and mixed with other gases prior to inhalation by the patient or subject before or during surgery. Other gas mixtures always include oxygen or air but may also include gases such as nitrous oxide.
- Nitrous oxide
- Isoflurane
- Halothane
- Desflurane
- Sevoflurane
Washington state has established permissible exposure limits for nitrous oxide (WAC 296-841-20025). Recommended exposure limits were established (1977) by NIOSH and the American Conference of Governmental Industrial Hygienists (ACGIH) (1989) for nitrous oxide and certain halogenated anesthetic gases. Refer to the document Anesthetic Gases: Safe Use Guidelines for more information.
The specific health effects for nitrous oxide and the halogenated anesthetic gases are summarized below. An acute exposure is defined as a short-term exposure (i.e., minutes to days) to a relatively high concentration of an anesthetic gas. A chronic exposure includes long term exposures (i.e., months to years) to relatively low concentrations of anesthetic gases.
Nitrous Oxide
Acute exposure can cause:
- Lightheadedness
- Shortness of breath
Chronic exposure has been linked to:
- Reproductive effects
- Neurologic disease
- Liver/kidney disease
Halogenated Anesthetic Gases
Acute exposure can cause:
- Central nervous system effects (headache, drowsiness, nausea, irritability)
- Transient blurring of vision
- Difficulties with judgement and coordination
- Liver and kidney disease
Chronic halogenated anesthetics exposure has been linked to:
- Reproductive effects
- Cancer
- Liver and kidney disease
- Asphyxia
For more information consult the document Anesthetic Gases: Safe Use Guidelines.