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A929
October 19, 2009
2:00 PM - 4:00 PM
Room Area M
Comparison of Effects of Propofol and Thiamilal Plus Sevoflurane on Automated QT Interval
  **   Makito Oji, M.D., Yoshiaki Terao, M.D., Ph.D., Tomomi Tanise, M.D., Makoto Fukusai, M.D., Ph.D., Koji Sumikawa, M.D., Ph.D.
Anesthesia, Nagasaki Rosai Hospital, Sasebo, Nagasaki, Japan
Background:

Various drugs including anesthetics could cause QT interval prolongation. It remains controversial whether propofol could prolong heart rate(HR)-corrected QT interval(QTc) or shorten QTc. The present study was carried out to determin QTc interval change during anesthetic induction with target-controlled infusion(TCI) of propofol in comparison with thyamilal plus sevoflurane.

Materials and Methods:

After approval of Institutional Research Committee, written informed consent was obtained from each patient. We studied 54 patients undergoing elective spine surgery. HR, non-invasive blood pressure(NIBP), 12-lead electrocardiogram(ECG), and bispectral index(BIS) were monitored for the study. Three-lead ECG was recorded continuously for the analysis of incidence of arrhythmia. All the patients received fentanyl, 3mcg/kg iv, prior to induction. The patients were allocated into one of two groups at random. Group P (n=27) received TCI of propofol, 5mcg/ml, and group S (n=27) received thiamylal, 5mg/kg iv, followed by sevoflurane, 3 to 5% inhaled concentration. Vecronium, 0.15mg/kg, was given 2min after starting the anesthetics. After anesthetic induction, TCI of propofol was controlled between 3 to 5mcg/ml in group P, and sevoflurane, 2 to 3% end-tidal, in group S to maintain BIS below 50. Tracheal intubation was performed 2.5min after the injection of vecronium. After intubation, the target concentration of propofol was reduced to 3mcg/ml in group P, and the end-tidal concentration of sevoflurane was decreased to 1% in group S. HR, NIBP, 12-lead ECG, and BIS were recorded immediately before fentanyl(T1), anesthetic agents(T2), muscle relaxant(T3), intubation(T4), and 2min after intubation(T5). QT interval were automatically measured by software(QTD-1; Fukuda Denshi, Tokyo, Japan), and were corrected by HR according to Bazzet formula. QTc intervals in 12-lead ECG were calculated as the mean value of consecutive three ECG waves at each measurement. Results were expressed as median(interquartile range). Intergroup comparisons were performed with Mann-Whiteney U test and chi-square test. Innergroup comparisons were performed with Friedman test and Wilcoxon test. Significance was determined as P < 0.05.

Results:

There were no significant differences in demographic characteristics between 2 groups. As shown in table, QTc interval was shortened in group P, and not significantly changed in group S after induction. After tracheal intubation, QTc interval was not significantly changed from baseline in group P, and was prolonged in group S. HR decreased at T4 in both groups. There was no significant difference in the incidence of arrhythmia between 2 groups.[table1]Conclusion:

During anesthetic induction, propofol shortens QTc, which is reversed by tracheal intubation, whereas thiamylal plus sevoflurane prolongs QTc after tracheal intubation.

From Proceedings of the 2009 Annual Meeting of the American Society Anesthesiologists.
Table 1- Change of HR and QTc in group P and S
VariableGroupT1 (baseline)T2 (fentanyl)T3 (agents)T4 (vecronium)T5 (intubated)
HRP75 (62, 93)74 (58, 83)68 (59, 75)63 (55, 69)*73 (66, 86)
(bpm)S70 (67, 74)67 (64, 78)73 (66, 77)64 (58, 68)*69 (62, 75)
QTcP439 (422, 455)432 (416, 442)*426 (410, 435)#*423 (412, 429)#*436 (423, 448)#
(msec)S442 (417, 461)438 (417, 457)445 (423, 467)445 (423, 467)459 (436, 482)*
median(interquartile range); #: p<0.05 vs. group S, *: p<0.05 vs. T1