Related Experiment Video
Updated: Aug 19, 2026

In Vitro Method to Control Concentrations of Halogenated Gases in Cultured Alveolar Epithelial Cells
Published on: October 23, 2018
Isocapnic hyperpnoea accelerates recovery from isoflurane anaesthesia
A Vesely1, J A Fisher, N Sasano
1Department of Anesthesia, University Health Network, University of Toronto, Toronto, Canada, M5G 2C4.
Background:
Hyperventilation should speed up elimination of volatile anaesthetic agents from the body, but hyperventilation usually results in hypocapnia. We compared recovery from isoflurane anaesthesia in patients allowed to recover with assisted spontaneous ventilation (control) and those treated with isocapnic hyperpnoea.
Methods:
Fourteen patients were studied after approximately 1 h of anaesthesia with isoflurane. Control patients were allowed to recover in the routine way. Isocapnic hyperpnoea patients received 2-3 times their intraoperative ventilation using a system to maintain end tidal PCO(2) at 45-50 mm Hg. We measured time to removal of the airway and rate of change of bispectral index (BIS) during recovery.
Results:
With isocapnic hyperpnoea, the time to removal of the airway was markedly less (median and interquartile range values of 3.6 (2.7-3.7) vs 12.1 (6.8-17.2) min, P<0.001); mean (SD) BIS slopes during recovery were 11.8 (4.4) vs 4.3 (2.7) min(-1) (P<0.01) for isocapnic hyperpnoea and control groups, respectively. Isocapnic hyperpnoea was easily applied in the operating room.
Conclusions:
Isocapnic hyperpnoea at the end of surgery results in shorter and less variable time to removal of the airway after anaesthesia with isoflurane and nitrous oxide.
More Related Videos
09:36Halogenated Agent Delivery in Porcine Model of Acute Respiratory Distress Syndrome via an Intensive Care Unit Type Device
Published on: September 24, 2020
07:15Preoxygenation Techniques for Tracheal Intubation in Critically Ill Adults Utilizing Oxygen Mask and Noninvasive Ventilation
Published on: December 5, 2025
Related Concept Videos
Stages of General Anesthesia
Inhalational Anesthetics: Overview
Hyperpnea and Hyperventilation
Acute Respiratory Failure-II
The underlying physiological abnormalities that contribute to hypoxemic respiratory failure include:
Acute Respiratory Failure-III
Acute Respiratory Failure-IV