[The effects of intravenous anesthetics, propofol, fentanyl and ketamine on the excitability of spinal motoneuron in human: an F-wave study].
We have investigated the effects of various intravenous anesthetics, propofol, fentanyl and ketamine on the excitability of spinal motoneuron using an F-wave analysis in a total of 28 patients. All patients were divided randomly into three groups as follows; 2 mg.kg-1 intravenous bolus injection followed by 6 mg.kg-1.h-1 infusion of propofol (P group), 1 mg.kg-1 intravenous bolus injection followed by 1 mg.kg-1.h-1 infusion of ketamine (K group), and 5 micrograms.kg-1 injection of fentanyl (F group). The F-wave was determined after supramaximal electrostimulation of the median nerve in distal point. After establishing stable baseline values, intravenous injection of one of the three anesthetics was applied. The F-wave was recorded 3 minutes after the time of bolus administration. We found a significant (P = 0.018) reduction of the persistence from 77.5 +/- 15.2 to 40.9 +/- 16.8% in the propofol group. On the other hand, no significant changes in F-wave parameters were found in ketamine, or fentanyl group. These results suggested that motoneuron excitability in spinal cord could be inhibited by anesthetic dose of propofol, but not by ketamine or fentanyl.
Kakinohana
M
M
Division of Anesthesia, Okinawa Prefectural Miyako Hospital.
Motonaga
E
E
Taira
Y
Y
Okuda
Y
Y
D000328:Adult; D000368:Aged; D018686:Anesthetics, Intravenous / Q000008:administration & dosage / Q000494:pharmacology*; D003864:Depression, Chemical; D004558:Electric Stimulation; D019054:Evoked Potentials, Motor / Q000187:drug effects*; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D007275:Injections, Intravenous; D007649:Ketamine / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D008475:Median Nerve / Q000502:physiology; D008875:Middle Aged; D009046:Motor Neurons / Q000187:drug effects* / Q000502:physiology; D015742:Propofol / Q000008:administration & dosage / Q000494:pharmacology*
D018686:Anesthetics, Intravenous; D007649:Ketamine; D005283:Fentanyl; D015742:Propofol