The effect of high spinal anesthesia on the renal hemodynamics and the excretion of electrolytes during osmotic diuresis in the hydropenic normal pregnant woman

Effect of dopamine on hypotension induced by spinal anesthesia

Chronically instrumented, near-term pregnant sheep were subjected to autonomic blockade with spinal anesthesia. Systemic arterial pressure, heart rate, and uterine blood flow decreased and uterine vascular resistance increased during the spinal blockade. Infusion of dopamine during the spinal hypotension corrected the disturbed circulatory parameters. These data provide evidence that: (1) the peripheral circulation of the near-term pregnant sheep is as sensitive as that of pregnant women to autonomic blockade, (2) the sensitivity is probably related to factors other than the changes in venous pressure in areas below the pelvis, and (3) dopamine represents a useful agent in the management of spinal hypotension.

Observations on the hemodynamic properties of a thiophanium derivative, Ro 2-2222 (arfonad), in human subjects

Observations on the hemodynamic properties of a thiophanium derivative (Arfonad) have been made on normotensive nonpregnant and pregnant subjects and on patients with hypertensive complications of pregnancy. The drug was given by single intravenous injections and by intravenous drip infusion. The hypotensive effects of single injections where compared with those of a standard tetraethylammonium chloride (TEAC) test. The authors observed that the hemodynamic effects of Arfonad were similar in some respects to those of tetraethylammonium chloride or spinal anesthesia. A fall in the cardiac output occurred when the blood pressure fell following Arfonad administration. The authors discuss these hemodynamic effects in terms of differences in response to ganglionic blocking agents of the various groups of subjects studied.