Effects of isoflurane-nitrous oxide and halothane-nitrous oxide anaesthesia on myocardial contractility assessed by transoesophageal echocardiography.
In order to evaluate the direct effect of isoflurane-nitrous oxide and halothane-nitrous oxide anaesthesia on cardiac contractility in 20 adults, we have used a method based on left ventricular end-systolic wall stress (LVESWS) vs velocity of circumferential fibre shortening with corrected heart rate (Vcfc), obtained by transoesophageal echocardiography. We found that LVESWS (index of afterload) decreased significantly with isoflurane-nitrous oxide (n = 10) in concentrations of 1.5-1.95 MAC, but there were no significant changes in LVESWS with halothane-nitrous oxide (n = 10). Vcfc decreased significantly with halothane-nitrous oxide in concentrations of 1.5-1.95 MAC, but this index did not change significantly with isoflurane-nitrous oxide. However, there was no significant difference between the two groups in LVESWS or Vcfc. In the analysis of the LVESWS-Vcfc relationship, myocardial contractility associated with isoflurane-nitrous oxide anaesthesia did not differ significantly from that associated with halothane-nitrous oxide anaesthesia at equiMAC concentrations. The results suggest that halothane-nitrous oxide anaesthesia, at 1.5-1.95 MAC, maintained myocardial contractility in similar anaesthetic concentrations to isoflurane-nitrous oxide.
Kikura
M
M
Department of Anaesthesiology and Intensive Care, Hamamatsu University School of Medicine, Japan.
Ikeda
K
K
D000328:Adult; D000769:Anesthesia, Inhalation; D001794:Blood Pressure / Q000187:drug effects; D002245:Carbon Dioxide / Q000502:physiology; D003864:Depression, Chemical; D004305:Dose-Response Relationship, Drug; D017548:Echocardiography, Transesophageal; D005260:Female; D006221:Halothane / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007530:Isoflurane / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000187:drug effects*; D009609:Nitrous Oxide / Q000494:pharmacology
D002245:Carbon Dioxide; D007530:Isoflurane; D009609:Nitrous Oxide; D006221:Halothane