Vital capacity and patient controlled sevoflurane inhalation result in similar induction characteristics.
OBJECTIVE
To compare patient controlled inhalational induction (PCI) with the most commonly used sevoflurane induction technique, vital capacity inhalational induction (VCI).


METHODS
Following approval of the Research Ethics Board, 124 outpatients undergoing knee arthroscopy were randomly assigned to receive either PCI or VCI sevoflurane followed by laryngeal mask airway (LMA) insertion and sevoflurane maintenance. In the PCI group, the circle circuit was not primed. The patients were asked to hold the facemask themselves and breathe normally with sevoflurane 8% in oxygen at a flow rate of 4 L x min(-1). In the VCI group, the circle circuit was primed and patients were asked to take vital capacity breaths with sevoflurane 8% at an oxygen flow rate of 8 L x min(-1). The LMA was inserted as soon as the patient's jaw was relaxed. Time from induction to LMA insertion was recorded and insertion conditions rated. The amount of sevoflurane used for LMA insertion was calculated. Vital signs were monitored at one-minute intervals until ten minutes after LMA insertion.


RESULTS
Demographic data were comparable. There were no differences with respect to LMA insertion time (PCI - 3.4 min vs VCI - 3.3 min), laryngospasm (PCI - 7% vs VCI - 5%), mean arterial pressure, heart rate, SaO(2) as well as patient's overall satisfaction.


CONCLUSIONS
PCI was comparable to VCI in sevoflurane induction with respect to the speed of induction, side effects during induction and patient satisfaction. However, PCI requires no special training and is widely applicable to all patient populations.
Yogendran
Suntheralingam
S
Department of Anesthesia, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada. Suntheralingam.yogendran@uhn.on.ca <Suntheralingam.yogendran@uhn.on.ca>
Prabhu
Atul
A
Hendy
Ayman
A
McGuire
Glenn
G
Imarengiaye
Charles
C
Wong
Jean
J
Chung
Frances
F
D000328:Adult; D016058:Analgesia, Patient-Controlled; D000769:Anesthesia, Inhalation; D018685:Anesthetics, Inhalation; D001182:Arthroscopy; D004569:Electroencephalography / Q000187:drug effects; D005260:Female; D006439:Hemodynamics; D006801:Humans; D017214:Laryngeal Masks; D008297:Male; D008738:Methyl Ethers; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D010149:Postoperative Pain / Q000453:epidemiology; D017060:Patient Satisfaction; D020250:Postoperative Nausea and Vomiting / Q000453:epidemiology; D011446:Prospective Studies; D000077149:Sevoflurane; D014797:Vital Capacity
D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane