Oxygen Uptake, Plasma Catecholamines and Cardiac Output during Neurolept‐Nitrous Oxide and Halothane Anaesthesias

Abstract

Cardiac output, oxygen uptake and plasma catecholamines were studied in patients both awake and during anaesthesia prior to and during upper abdominal surgery. Two different forms of anaesthesia were used: neurolept-nitrous oxide (NLA) and halothane (HALO) anaesthesia. Oxygen uptake was determined by using a masspectrometer, and cardiac output was measured according to the Fick principle. Plasma catecholamines were analysed by high performance liquid chromatography. Cardiac output fell by 40% during NLA and by 30% during HALO. Concomitantly, the oxygen uptake fell by 40% and 35%, respectively. A linear relationship between cardiac output and oxygen uptake could be established both in the awake state and during anaesthesia, with no significant change in the slope or position of the regression line when anaesthesia was commenced. Ventricular filling pressures fell during both anaesthetic procedures. Adrenaline fell to half the plasma concentrations seen in normal subjects under resting conditions, while noradrenaline returned to normal from an initially 30-40% increased value. Surgery caused no significant changes in either cardiac output or oxygen uptake, whereas plasma adrenaline increased by 20 times and noradrenaline by 60-90%. The findings suggest that the reduced oxygen uptake during anaesthesia causes the fall in cardiac output rather than any cardiodepressant action of the anaesthetic. It is possible that the anaesthetic depresses whole-body metabolism by either blocking the effects of catecholamines or interfering with cellular metabolism.

Temporary adrenal dysfunction with descending thoracic aortic occlusion

“…However there was significant time effect on the cortisol levels (ANOVA p B0.001). More specifically in the DT AXC study group the cortisol level decreased from baseline before unclamping (8.692.6 mg/dl vs. 10.292.6 mg/dl, p 00.048), although this difference was considered marginal when adjusting the alpha level for multiple comparisons. Cortisol levels in the DT AOC group were lower than baseline 30 min after restoration of flow to the distal circulation (7.391.5 mg/dl vs. 10.292.6 mg/dl, p00.004) and then returned to normal.…”

Vascular Aging and Hemodynamic Stability in the Intraoperative Period

“…Anesthetics can influence hemodynamic stability directly by altering cardiac function, vascular reactivity, or affecting cardiovascular reflexes (Mallow et al, 1976; Westenskow et al, 1978; Bennett and Stanley, 1979; Waxman et al, 1980; Brismar et al, 1982; Fairfield et al, 1991). Because cardiac and vascular function are in many ways compromised with aging, the circulatory effects of anesthetics are exacerbated in the elderly (Tokics et al, 1985).…”

Aventilatorischer Massenfluss während Apnoe

“…In der Literatur wird in tiefer Narkose ein um bis zu 35% reduzierter O 2 -Verbrauch gegenüber dem Wert im Wachzustand beschrieben [6]. aus in den Lungenkapillaren ein pulsatiler Fluss existieren [22].…”