Central haemodynamics and regional blood flow during halothane-nitrous oxide anaesthesia and controlled ventilation. An experimental study in the rat.
The haemodynamic effects of halothane-N2O/O2 anaesthesia with controlled ventilation were studied in rats, using the microsphere method. Mean arterial blood pressure was significantly reduced but only minor effects on cardiac output (CO), heart rate, and systemic vascular resistance were seen. During anaesthesia, there were significantly increased fractions of CO delivered to brain, lungs, small intestine and liver (hepatic artery), while the fractions to spleen, stomach and carcass were decreased. Fractional distribution and regional blood flow to heart, kidneys, adrenals and preportal area remained unchanged. When anaesthesia was prolonged from 60 to 90 min, no further changes in central or regional haemodynamics were seen. Considering the minor effects on central haemodynamics and the absence of changes in central and regional haemodynamics at 60 and 90 min, this anaesthesia model should be useful in experimental research.