Isocapnic hyperpnoea shortens postanesthetic care unit stay after isoflurane anesthesia.
BACKGROUND
We conducted a prospective controlled clinical trial of the effect of isocapnic hyperpnoea (IH) on the times-to-recovery milestones in the operating room (OR) and postanesthetic care unit (PACU) after 1.5 to 3 hours of isoflurane anesthesia.


METHODS
Thirty ASA grade I-III patients undergoing elective gynecological surgery were randomized at the end of surgery to either IH or the conventional recovery (control). Six patients with duration of anesthesia of <90 minutes were excluded from the analysis. The anesthesia protocol included propofol, fentanyl, morphine, rocuronium, and isoflurane in air/O(2). Unpaired t tests and analyses of variance were used to test for differences in times-to-recovery indicators between the two groups.


RESULTS
The durations of anesthesia in IH and control groups were 140.8 + or - 32.7 and 142 + or - 55.6 minutes, respectively (P = 0.99). The time to extubation was much shorter in the IH group than in the control group (6.6 + or - 1.6 (SD) vs. 13. 6 + or - 3.9 minutes, respectively; P < 0.01). The IH group also had shorter times to eye opening (5.8 + or - 1.3 vs. 13.7 + or - 4.5 minutes; P < 0.01), eligibility for leaving the OR (8.0 + or - 1.7 vs. 17.4 + or - 6.1 minutes; P < 0.01), and eligibility for PACU discharge (74.0 + or - 16.5 vs. 94.5 + or - 14.7 minutes; P < 0.01). There were no differences in other indicators of recovery.


CONCLUSIONS
IH accelerates recovery after 1.5 to 3 hours of isoflurane anesthesia and shortens OR and PACU stay.
Katznelson
Rita
R
Department of Anesthesia, Toronto General Hospital, Eaton North 3-453, 200 Elizabeth Street, Toronto, Ontario M5G 2C4, Canada. rita.katznelson@uhn.on.c
Van Rensburg
Adriaan
A
Friedman
Zeev
Z
Wasowicz
Marcin
M
Djaiani
George N
GN
Fedorko
Ludwik
L
Minkovich
Leonid
L
Fisher
Joseph A
JA
D000328:Adult; D000762:Anesthesia Recovery Period; D018685:Anesthetics, Inhalation; D017558:Elective Surgical Procedures; D005260:Female; D013509:Gynecologic Surgical Procedures; D006801:Humans; D006985:Hyperventilation; D007530:Isoflurane; D007902:Length of Stay; D008875:Middle Aged; D009873:Operating Rooms; D011446:Prospective Studies; D011997:Recovery Room; D013997:Time Factors
D018685:Anesthetics, Inhalation; D007530:Isoflurane