The Importance of Compensating Vasoconstriction in Unanesthetized Areas in the Maintenance of Blood Pressure During Spinal Anesthesia 1

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

“…Peripheral Blood Flow. The data in this report substantiate the observations of others 6' 11,29,31,38,40 that the rate of blood flow increases in the extremities after spinal block, and that in the case of low spinal anesthesia there is a compensatory vasocontriction in the upper extremities. The increased blood flow in the anesthetized fingers and toes is maintained only so long as the mean blood pressure remains above the normal arteriolar pressure.…”

Cardiovascular responses to bladder distension in paraplegic patients

“…This splanchnic vasoconstriction could be responsible for the rise in peripheral resistance and the resulting rise in blood pressure. This explanation would be in close agreement with that put forward by Neumann et al (1945), who observed a dilatation of the vessels of the toes in all patients during spinal anaesthesia but observed vasoconstriction in the fingers in all patients in whom the blood pressure was maintained.…”

“…The work of Milwidsky & de Vries (1948), Pugh & Wyndham (1950) and of Brigden, Howarth & Sharpey-Schafer (1950) emphasized the necessity of a knowledge of cardiac output and muscle blood flow in order to interpret the vascular disturbances in the allied condition of spinal anaesthesia. The relative importance of changes in heart output and peripheral vasoconstriction was also discussed by Neumann, Foster & Rovenstine (1945), in the light of measurements of blood flow in the skin only.…”

Extradural Block in Major Surgery of the Hip

“…Figure 2 is an attempt to illustrate the rough correlation that exists between the maximum fall in systolic pressure (expressed here as a percentage of tie pre-operative level) and the level of the preoperative systolic pressure. These results are in line with those reported by Pugh and Wyndham (1950) in spinal anaesthesia, and are probably explicable in the light of the findings of Neumann, Foster and Rovenstine (1945) and Milwidsky and de Vries (1948). Plethysmographic and other studies by these workers revealed a compensatory vasoconstriction above the level of the block.…”