Comparative effects of etomidate, ketamine, propofol, and fentanyl on myocardial contractility in dogs.
OBJECTIVE
The present study was carried out to determine the direct effects of etomidate, ketamine, propofol, and fentanyl on myocardial contractility, and whether fentanyl would enhance the myocardial depression caused by propofol.


METHODS
The anesthetics were injected directly into the circuit that supplied blood to the left circumflex coronary artery (LCX) in anesthetized open-chest dogs. Myocardial contractility was evaluated from measurements of percent segmental shortening (%SS).


RESULTS
Etomidate, ketamine, and propofol significantly reduced %SS in a dose-dependent manner. The %SS values with 1.6 and 3.2 mg of etomidate were similar to those with 3.2 and 6.4 mg of ketamine, respectively, and the %SS value with 6.4 mg of propofol was similar to those with 3.2 and 6.4 mg of ketamine. Fentanyl alone had no effects on myocardial performance and did not influence the effect of propofol on %SS.


CONCLUSIONS
On the basis of clinical doses, the direct myocardial depressant effect of ketamine is more than twice as potent as that of etomidate and slightly more than that of propofol. Fentanyl has no inotropic effect and does not enhance the direct myocardial depressant effect of propofol.
Kawakubo
A
A
Department of Anesthesia, Hamamatsu Medical Center, 328 Tomizuka, Hamamatsu, Shizuoka 432-8002, Japan.
Fujigaki
T
T
Uresino
H
H
Zang
S
S
Sumikawa
K
K