'Anestheticography': on-line monitoring and documentation of inhalational anesthesia.

The safe practice of inhalational anesthesia requires control over the amount of volatile anesthetic delivered to the patient. With minimal fresh gas flow this is facilitated by continuous monitoring and recording of the agent's concentration ('Anestheticography'). Alterations brought about by routine clinical maneuvers become visible. We recorded the course of the inspiratory and expiratory concentration of volatile anesthetic (Isoflurane) by infrared absorption and a trend recorder. Changing the carrier gas composition during high flow from 75% to 25% nitrous oxide in oxygen resulted in a 10% increase of the inspiratory isoflurane concentration. Activating the oxygen bypass or exchanging …