Purpose

The purpose of this document is to provide guidelines regarding recommended scheduling for anesthesia machine/vaporizer calibration and maintenance. You are advised to follow the manufacturer recommendations if they differ from this document.

Policy

Anesthesia machines and vaporizers must be in good working condition to reduce anesthetic gas leaks, to have the best performance of scavenging equipment, and ensure the appropriate percentage of anesthetic is being delivered. Personnel must be trained in the proper use of anesthetic machines and vaporizers prior to operation.
Each piece of equipment involved in the delivery of inhalant anesthetics should be evaluated regularly to assure its proper function and integrity.

Guidelines 

1. Vaporizer Service:
   Accuracy of anesthetic agent delivery must be verified annually or any time the vaporizer has not been in service for more than a year. If the verified delivery is +/- 10% out of calibration, the unit should be serviced by an authorized service center.
   
   All anesthetic vaporizers should be serviced by qualified personnel (authorized service center) as recommended by the manufacturer. Manufacturer recommendations range from one to three years depending on the model.
   
   Discoloration (yellowish-brown) in the “Fill” sight glass of a vaporizer is a clear sign of the need for service by an authorized service center.
2. Waste Gas Scavenging Systems:
   An effective mechanism of waste gas scavenging is essential as waste anesthetic gases may adversely affect liver, kidney and the central nervous system of chronically exposed personnel.
• F-Air canisters: Charcoal canisters may be used to absorb halogenated waste gases, but not nitrous oxide. A log indicating the hours used must be indicated on the side of the canister, the total hours must not exceed 12 (or as indicated by the manufacturers recommendation); alternately the canister may be weighed PRIOR to its initial use and again at each use thereafter. When the weight indicates an increase of 50 gm from the initial weight, the canister must be discarded and a new canister installed.
• Soda lime/Baralyme (CO2 absorbers) should be change regularly. CO2 absorbers react with water; the pH change of becoming saturated with CO2 will activate a change in the ethylene violet dye indicator contained in these absorbers. These indicators can change back to white-grey if enough time is allowed, this however does not indicate the absorbers are still functional, therefore the absorbers should be change as soon as a color change is indicated. The absorbers should be disposed of as biohazardous waste.
• Fume hood: Open drop anesthesia techniques must be conducted in a fume hood that has been tested and certified by Physical Plant.
3. Documentation:
   Vaporizer must have documentation of date of delivery test with the initials for the person who performed the test and the test results. Vaporizers should have a certificate of the calibration date affixed after each service.
4. Services available:
   Following are a list of services available on campus and thru private industry.
1. For verification of gas delivery concentration of anesthesia machines/vaporizers:

• CLAS (Center for Laboratory Animal Science)
  CLAS Bldg. R-1
  (530) 752-0514

• Med. Dean’s Office/Dept. of Surgery
  CLAS Bldg. H-1
  (530) 752-7756

2. Qualified Service Centers:

• Vet Equip
  P.O. Box 10785
  Pleasanton, CA 94588-0785
  (800) 466-6463
  (925) 463-1828
  (925) 463-1943 FAX
  http://www.vetequip.com/

• Highland Medical
  26111 Ynez Rd., Suite 15
  Temecula, CA 92591
  (800) 826-5951
  http://www.highlandmedical.net/

References

OSHA Health Care Workers Guidelines/Chap5b

Approved by IACUC: 9/23/04