Occupational exposure to inhalational anesthetics during cardiac surgery on cardiopulmonary bypass.

Background: Eventual hazards from occupational exposure of operating room personnel to inhalational anesthetic agents cannot yet be definitively excluded. We determined if occupational exposure of operating room personnel to waste anesthetic gases during cardiopulmonary bypass (CPB) complies with the established governmental limits.

Methods: Ten adults underwent inhalational anesthesia for coronary artery bypass grafting with nitrous oxide and either sevoflurane (n = 5) or desflurane (n = 5). The administration of inhalational anesthetic agents was stopped before initiation of CPB. Gas samples were obtained before and during CPB every 90 seconds from the breathing zones of anesthesiologist (A), surgeon (S), and perfusionist (P). Time-weighted averages (TWA) over the time of exposure were calculated.

Results: The surgeon's exposure to nitrous oxide was 9.3 +/- 1.9 parts per million (ppm) before and 3.0 +/- 1.4 ppm during CPB (A: 6.7 +/- 1.1 ppm and 0.5 +/- 0.1 ppm; P: 3.7 +/- 1.4 ppm during CPB). Occupational exposure to desflurane was 0.21 +/- 0.10 ppm before and 0.62 +/- 0.28 ppm during CPB for the surgeon (A: 0.02 +/- 0.01 ppm and 0.02 +/- 0.003 ppm; P: 0.82 +/- 0.26 ppm during CPB), thereby exceeding the given limit of 0.5 ppm. Exposure levels of sevoflurane were below the 0.5 ppm limit at all times, as were nitrous oxide levels (threshold limit: 25 ppm).

Conclusions: Although occupational exposure to inhalational anesthetic agents was low at most times during the study and none of the operating room staff complained about subjective or objective impairment or discomfort, all measures must be taken to further minimize occupational exposure, including sufficient air conditioning and routine use of waste gas scavenging systems on CPB equipment.