[Desflurane and errors of gas selection on vaporizer analyzer]

Area of Science:

• Anesthesiology
• Medical Device Technology
• Patient Safety

Background:

• Monochromatic infrared gas spectrometers (MIS) calculate volatile agent (VA) concentration using IR absorption and a specific gain factor.
• These devices cannot identify the actual VA present, leading to potential discrepancies between displayed and actual concentrations.
• While desflurane vaporizers prevent misfilling, erroneous VA selection on the MIS remains a risk.

Purpose of the Study:

• To evaluate the displayed concentrations on a Capnomac Ultima (Datex) monitor following incorrect volatile agent (VA) selection.
• To categorize the potential errors arising from misidentifying anesthetic agents.

Main Methods:

• Desflurane, isoflurane, or enflurane were delivered at constant concentrations.
• The MIS successively measured and displayed concentrations for desflurane, sevoflurane, isoflurane, enflurane, and halothane.
• Displayed concentrations were compared against actual vapor concentrations.

Main Results:

• Errors were categorized into dangerous (displayed concentration much lower than actual, e.g., desflurane/sevoflurane misselection), evident (displayed concentration >10 vol%), and uncomfortable (displayed and actual concentrations similar, e.g., isoflurane instead of desflurane).
• Dangerous errors occurred when desflurane or sevoflurane were erroneously selected.
• Uncomfortable situations arose when isoflurane was selected instead of desflurane, requiring careful device checking.

Conclusions:

• Erroneous volatile agent (VA) selection on monochromatic infrared gas spectrometers (MIS) can lead to significant and potentially dangerous miscalculations of anesthetic agent concentrations.
• The risk of misidentification necessitates vigilant monitoring and verification of device settings by clinicians.
• Implementing strict checking protocols for MIS settings is crucial for patient safety in anesthesia delivery.