Studies of Hemodynamic Changes in Humans Following Induction of Low and High Spinal Anesthesia

Abstract

Low and high spinal anesthesia were administered to a group of 10 waking patients without the use of vasopressor drugs. Preliminary evidence does not support the view that the induced hypotension is accompanied by significant splanchnic vasoconstriction or by homeostatic diversion of blood from the splanchnic bed to maintain the circulation in "more vital" areas. IN PREVIOUS communications we havepresented the data on the general hemodynamic and blood oxygen changes induced in humans by the administration of low and high spinal anesthesia."' 1' This paper deals with the changes observed in the splanchnic vascular bed in two groups of patients receiving low and high spinal anesthesia, but in whom no surgical procedure was performed. The general technic and methods have been previously described' and mention will be made of the technic only as it applies to the problem at hand. MATERIAL AND METHODSTen patients, nine men and one woman, with various medical diseases, were selected at random from the medical wards. Their ages ranged from 31 to 77 years; the average age was 52.4 years. Although none had active infections or temperature elevations at the time of the study, it must be emphasized that only one of these patients was entirely free of disease, and that most of them could not be considered normal control subjects. In three there was a history of chronic alcoholism, one had a fatty liver which was thought to be healed, and another This investigation was supported in part by a grant from the Cleveland Area Heart Society, Cleveland, Ohio. 894 was found to have mild congestive failure, conditions which are all known to derange the normal liver function and splanchnic blood flow. For the purpose of this study, however, the selection of completely normal individuals was not deemed necessary.After an overnight fast, 0.1 to 0.2 Gm. of pentobarbital sodium was administered and the patients were transported to the cardiovascular laboratory where the air temperature was maintained at 24 C., and the humidity was kept fairly constant. The right hepatic vein was uniformly catheterized employing a 6 to SF Goodale birdseye catheter, introduced into a medial arm vein, and the position of the tip checked repeatedly by fluoroscopic observation. An indwelling round tip no. 16 venous needle was introduced into a lateral arm vein for delivery of the bromsulfalein drip.

Effects of Subarachnoid Spinal Nerve Block and Arterial P Co 2 on Colon Blood Flow in the Dog

“…Nevertheless, the decrease in colon vascular resistance was greater than that in total peripheral resistance. This is contrary to the findings of Mueller, Lynn and Sancetta (1952), who found no significant change in splanchnic vascular resistance during high spinal anaesthesia at a time when total peripheral vascular resistance was decreased.…”