Direct blood pressure monitoring in patients with pheochromocytoma

In patients with pheochromocytoma, blood pressure was monitored continuously for 2 days using direct measurement techniques. Systolic blood pressure sometimes increased to more than 300 mmHg. These sudden elevations of blood pressure were associated with increased levels of plasma catecholamines. Pre-operative prazosin and propranolol therapy lowered mean systolic and diastolic blood pressure throughout the 2 day observation periods and was associated with decreased hematocrit levels. However, these agents did not prevent the rapid elevation of blood pressure.