Improved Patient Recovery After Anesthesia With Hypercapnia Hyperpnoea

Patients received intravenous fentanyl at the discretion of the attending anesthesiologist. Anesthesia was induced with a remifentanil infusion, lidocaine, propofol, and rocuronium or succinylcholine at the anesthesiologist's discretion. Maintenance anesthesia was 6% end tidal desflurane with oxygen flows of 2 L/min (though clinicians could deviate from this at their discretion). Clinicians were directed to maintain blood pressure at ±20% of baseline. A baseline remifentanil infusion was used throughout each case, and both remifentanil and fentanyl were titrated at the anesthesiologist's discretion. Ventilation was adjusted to maintain an end tidal carbon dioxide concentration (EtCO2) of 35 mmHg. Ondansetron 4 mg was given prophylactically before the end of surgery.

The Quick Emergence Device is placed between the endotracheal tube and the anesthesia breathing circuit to enable hypercapnia when ventilation is increased. The end-tidal gas sampling line is connected between the device and the endotracheal tube connector. Minute ventilation is doubled and the EtCO2 is elevated to approximately 48 mmHg from the previous maintenance level of 35 mmHg.