Renal vasoconstriction produced by ether and cyclopropane anaesthesia

Abstract

In man and animals, ether and cyclopropane anaesthesia bring about substantial renal vasoconstriction. Opinion differs as to whether its cause is nervous, humoral or the local action of the anaesthetic. The following investigation attempts to decide this point.The method used was identical in principle with that employed by Richards & Plant (1922). Single kidneys of anaesthetized dogs were perfused at a controlled rate and the changes in perfusion pressure induced by ether or cyclopropane were recorded. METHODSSixteen 5-16 kg mongrel dogs were anaesthetized with pentobarbitone sodium (23-38 mg/kg) and a constant level of anaesthesia maintained by continuous intravenous infusion (0.04 mg/kg/min).After intubation, 100% oxygen was given in closed circuit with a carbon dioxide absorber. One or other renal artery was cannulated through a flank incision, care being taken as far as was possible to avoid damage to the renal nerves which could be seen along the surface of the artery. The blood for perfusion was led into the flow-meter and pump from a cannula in the left carotid artery. Heparin (30-40 mg) was given before cannulation.When the kidney was denervated, all structures seen approaching the hilus, other than the artery, vein and ureter, were severed. Completeness of denervation was confirmed by the absence of prompt renal vasoconstriction during a rapid bleed of 100 ml. of blood from the carotid artery into the reservoir, the blood being immediately retransfused. In two dogs, so that denervation should be unequivocal, the perfused kidney was removed from the body and placed in saline at a thermostatically controlled temperature of 38.5°C. In these experiments on the isolated kidney a cannula was placed in the renal vein, and the blood returned from the kidney to the general circulation via another cannula in the left jugular vein. Plastic Portex tubing was used throughout and the circuit was charged with 140 ml. of a 6 % solution in normal saline of Dextran (Intradex, Crooke's Laboratories).The flow-meter has been described previously (de Wardener & Miles, 1952). The pump, however, was a new adaptation in which the motor, piston and platform of the standard Dale Schuster pump were used (Fig. 1). At each stroke its piston was made to compress a short length of rubber tubing, thus forcing a quantity of blood past an outlet valve in the direction of the kidney; an inlet valve prevented flow in the reverse direction. Rubber flap valves were used.

Renal Circulatory Responses to General Anaesthesia in the Rabbit: Studies Using Radioactive Microspheres

“…The demonstration of reduced natriuresis in the presence of an increase in blood flow to the deep renal cortex in rabbits anaesthetized with ether provides a further example of dissociation between increase in deep cortical blood flow and sodium excretion. Miles & De Wardener (1952) distinguished the direct renal vasodilator effects of ether from a vasoconstrictor effect mediated via the autonomic nervous system. It is clear from whole-animal studies (D. J. Warren & J. G. G. Ledingham, unpublished work) that ether stimulates the sympatho-adrenal system.…”

The Effects of Some Anaesthetics and Ancillary Agents on Adrenoceptive Receptors

“…It is worth nothing, however, that ether would not be the best choice as an anaesthetic agent for an animal in a pre-existing state of acidosis before induction of anaesthesia. Another effect of enhanced sympathoadrenal activity is depression of renal function; constriction of the renal vascular bed and consequent reductions in renal blood flow and the excretion of water and electrolytes occur during anaesthesia (Habif et a/., 1951 ; Miles and de Wardener, 1952). The modifications of renal function are rapidly reversed in the post-anaesthetic phase.…”

Blood serum fluoride levels with methoxyflurane anaesthesia

“…[4][5] Until approximately 10 years ago, inhalational and parenteral anaesthetics administered judiciously and even in moderate overdose had not been found to cause a direct adverse effect on the renal parenchyma in animals or man unless they accompanied or followed severe surgical trauma and multiple blood transfusions. Nevertheless, urine output is almost invariably reduced during surgical anaesthesia, with reductions in renal blood flow, glomerular filtration rate and osmolar clearance.…”