Vascular reactivity to phenylephrine and angiotensin II: comparison of direct venous and systemic vascular responses.

The objective of this study was to determine the relationship between peripheral venous responsiveness (use of the dorsal hand vein compliance technique) and systemic vascular responsiveness (measurement of blood pressure changes) to phenylephrine and angiotensin II in humans. There was a significant correlation (r = 0.70, p less than 0.02) between the dose causing a 20 mm increase in mean arterial pressure and the dose producing half-maximal response in the hand vein (log ED50) for phenylephrine but not for angiotensin II. There was no correlation between the systemic responses to angiotensin II and phenylephrine, but there was a significant correlation (r = 0.70, p less than 0.02) between the log ED50 measurements for phenylephrine and angiotensin II in the hand vein experiments. These findings suggest that systemic and hand vein responsiveness to phenylephrine are similar. Consequently, in evaluating alpha-adrenergic receptor mediated responses, the dorsal hand vein compliance approach offers a satisfactory alternative to the use of systemic hemodynamic changes.