Occupational exposure to sevoflurane during cardiopulmonary bypass

Volatile anaesthetic agents are widely used for maintenance of anaesthesia in all kinds of surgical procedures. Despite the implementation of measures such as adequate ventilation of the operating room and the use of efficient scavenging systems, concern remains about the risks for occupational exposure, especially in situations associated with an increased risk of anaesthetic gas waste, such as with the use of volatile anaesthetic agents on cardiopulmonary bypass. The present contribution reports the results of a preliminary safety assessment involving measurements of sevoflurane concentrations in the ambient air of a cardiac surgery operating room. In 22 cardiac surgical procedures with cardiopulmonary bypass (11 with open and 11 with closed venous reservoir), measurements of trace concentrations were obtained every 10 min at the following sites: at the outlet of the oxygenator, at the outlet of the cardiotomy reservoir, in the breathing zone of the perfusionist and above the surgical field. The concentrations were measured on-line using a photoacoustic infrared spectrometer. Mean sevoflurane waste concentrations remained consistently below the recommended target value of 4.68 ppm throughout the observation period at the different measurement sites. These results indicate that, with the use of sevoflurane on cardiopulmonary bypass, the recommended levels for occupational exposure are not exceeded, provided adequate operation room ventilation and waste gas scavenging is performed.