Apparent Dead Space with the Anesthetic Conserving Device, AnaConDa®: A Clinical and Laboratory Investigation.

摘要

The anesthetic conserving device (ACD) reduces consumption of volatile anesthetic drug by a conserving medium adsorbing exhaled drug during expiration and releasing it during inspiration. Elevated arterial CO2 tension (PaCO2) has been observed in patients using the ACD, despite tidal volume increase to compensate for larger apparatus dead space. In a test lung using room temperature dry gas, this was shown to be due to adsorption of CO2 in the ACD during expiration and release of CO2 during the following inspiration. The effect in the test lung was higher than in patients. We tested the hypothesis that a lesser dead space effect in patients is due to higher temperature and/or moisture attenuating rebreathing of CO2.