[Effect of spinal anesthesia on peripheral hemodynamics]

Abstract

In eight persons central hemodynamic parameters as well as peripheral circulatory parameters were measured before and during spinal anaesthesia (L3/4; 5 ml Carbostesin mit Adrenalin): heart rate, arterial pressure, central venous pressure, peripheral venous pressure, peripheral blood flow, venous capacity (Cv 70) using a venous pressure of 70 mm Hg (lethysmographic method) as well as intravascular basic volume. Intravascular basic volume and the venous capacity are representing total intravascular volume; changes in this parameter- in correlation to a well defind intravenous pressure - give information on the distensibility of capacitance vessels. During spinal anesthesia an increase in resting blood flow of the calf as well as in total blood volume was noted as a result of a decreasing total peripheral resistance and changes in blood distribution (shunting, nutritive blood supply). Intravascular total blood volume in the calf increased from 9.7 +/- 1.0 ml/100 ml to 10.9 +/- 1.1 ml/100 ml, being caused mainly by changes in basic volume not so much by changes in venous capacity. These results may be interpreted as an increase in distensibility of the low pressure vessels during spinal anesthesia.