Blood circulation in the kidney of the cat under methoxyflurane (penthrane) anaesthesia

In order to establish whether methoxyflurane causes any change in renal vascular resistance, the renal venous flow was measured by means of a drop recording technique in six cats under methoxyflurane anaesthesia. Arterial pressure was recorded simultaneously, and the renal vascular resistance was calculated. Methoxyflurane caused a significant reduction of the renal vascular resistance to about 85% of control value at an anaesthetic depth characterised by loss of the corneal reflex. At a deeper anaesthetic stage characterised by steady state circulation and absence of any reflexes, no further significant fall in renal vascular resistance occurred. Autoregulation and depression of the sympathetic activity are assumed to explain the reduction of the renal vascular resistance.