Effects of nitrous oxide on haemodynamic and electroencephalographic responses induced by tetanic electrical stimulation during propofol anaesthesia.
We studied the effect of nitrous oxide on haemodynamic and electroencephalographic responses caused by noxious stimulation during propofol anaesthesia. Thirty-four patients (ASA I-II) were anaesthetised with propofol 3 mg x kg(-1) and were randomly allocated to receive either 60% nitrous oxide in oxygen or 40% oxygen in air. Anaesthesia was maintained using propofol infusion of 10 mg x kg(-1) x h(-1) for the first 10 min, 8 mg x kg(-1) x h(-1) for the next 10 min and 6 mg x kg(-1) x h(-1) thereafter. Thirty minutes after the induction of anaesthesia, tetanic electrical stimulation (80 mA, 100 Hz) was applied to the ulnar nerve. Tetanic stimulation significantly increased blood pressure and heart rate in both groups (p < 0.005 or less), but did not induce any arousal pattern on the electroencephalograph. Nitrous oxide significantly attenuated the tetanic stimulation-induced increase in blood pressure (p < 0.05 or less), but not the heart rate.
Inada
T
T
Department of Anaesthesiology, Kansai Medical University Hospital, Moriguchi, Osaka, Japan.
Shingu
K
K
Nakao
S
S
Nagata
A
A
D000328:Adult; D019162:Anesthetics, Combined / Q000494:pharmacology*; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D018686:Anesthetics, Intravenous / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D004558:Electric Stimulation; D004569:Electroencephalography / Q000187:drug effects*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009609:Nitrous Oxide / Q000494:pharmacology*; D015742:Propofol / Q000494:pharmacology
D019162:Anesthetics, Combined; D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D009609:Nitrous Oxide; D015742:Propofol