Hemodynamic observations during paroxysmal hypertension in a pregnancy with pheochromocytoma.

A patient with pheochromocytoma diagnosed at 17 weeks' gestation was studied at rest, during an episode of paroxysmal hypertension, and during phenoxybenzamine treatment. Cardiac output was estimated noninvasively by Doppler technique. During paroxysmal hypertension, the mean blood pressure was 102 mmHg, cardiac output fell by 40%, and systemic vascular resistance rose by 250%. Phenoxybenzamine treatment did not change the resting cardiac output or systemic vascular resistance. These observations suggest that serious fetal compromise might occur even with mild episodes of hypertension associated with pheochromocytoma.