[O2 uptake and CO2 production during total intravenous propofol-alfentanil anesthesia under steady-state conditions. Is O2 uptake a parameter for assessing the depth of anesthesia?].
Depending on surgical and anaesthesiological procedures, anaesthesia leads to a reduction of O2 uptake (VO2), CO2 production (VCO2) and resting energy expenditure (REE). A controversial discussion on the degree of metabolic depression has continued in the literature fueled by a lack of studies in patients under standardised conditions. The goal of this study was to evaluate whether O2 consumption and/or CO2 production can be correlated to various depths of anaesthesia and whether VO2 could be a parameter to control narcosis. 12 patients (ASA I-II) scheduled for urological surgery of the lower abdomen, were given total intravenous anaesthesia with propofol and alfentanil. During a 60 minutes period the patients were first anaesthesized with an ED50 and then titrated to a dosage correlating with an ED95. The premedicated but awake patients each showed a REE which was about 10% below the calculated basal metabolism. Steady-state general anaesthesia led to an approximately 30% reduction of VO2, VCO2 an REE. Patients with adequate anaesthesia revealed no changes in oxidative metabolism with increased or decreased depth of anaesthesia. VO2 as a leading parameter proves to be problematic. It is useful as a measure for insufficient depth of general anaesthesia but fails to indicate overshooting anaesthesia depth.
Hausmann
D
D
Institut für Anästhesiologie, Rheinische Friedrich-Wilhelms-Universität Bonn.
Stoeckel
H
H
Krajewski
W
W
Schüttler
J
J
D000328:Adult; D015760:Alfentanil; D000771:Anesthesia, Intravenous; D002245:Carbon Dioxide / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology*; D015742:Propofol
D002245:Carbon Dioxide; D015760:Alfentanil; D015742:Propofol
O2-Aufnahme und CO2-Produktion bei total intravenöser Propofol-Alfentanil-Narkose unter Steady-State-Bedingungen. Ist die O2-Aufnahme ein Parameter zur Abschätzung der Narkosetiefe?