Changes in the T-wave amplitude of ECG during isoflurane anaesthesia.
R/T-wave amplitude ratio of electrocardiogram (ECG), heart rate (HR) and systolic arterial pressure (SAP) were recorded in 15 patients awake, at 1 minimal alveolar concentration of isoflurane before and during surgery, and in deep anaesthesia (electroencephalogram burst suppression) during surgery. R/T-wave amplitude ratio and HR were sensitive to both surgery and changes in the level of isoflurane anaesthesia; induction of anaesthesia, skin incision and the rapid increase in the concentration of isoflurane all significantly decreased the T-wave amplitude, without influence on the R-wave. Changes in the T-wave amplitude correlated directly to HR. SAP increased at skin incision and decreased when the anaesthesia was deepened. The authors conclude that the R/T-wave amplitude ratio of ECG provides a reliable method for monitoring the sympathetic tone during isoflurane anaesthesia.
Annila
P
P
Department of Clinical Sciences, Tampere University Hospital, Finland.
Jäntti
V
V
Lindgren
L
L
Yli-Hankala
A
A
D000328:Adult; D000769:Anesthesia, Inhalation; D001794:Blood Pressure / Q000187:drug effects; D062109:Dermatologic Surgical Procedures; D004562:Electrocardiography / Q000187:drug effects*; D004569:Electroencephalography / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007530:Isoflurane / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D013514:Surgical Procedures, Operative; D013997:Time Factors
D007530:Isoflurane