The patient is placed on appropriate preoperative medications and is taken for surgical removal of the tumor. During the procedure, he rapidly becomes hypotensive. His blood pressure falls from 110/89 mm Hg to 80/50 mm Hg. Which of the following is the most appropriate therapy for this patient’s hypotension?
- A. Bolus of normal saline followed by continuous normal saline infusion [55%]
- B. Dobutamine infusion [9%]
- C. Dopamine infusion [14%]
- D. Intravenous colloid bolus [2%]
- E. Intravenous phentolamine bolus [20%]
Even with adequate preoperative alpha blockade and adequate fluid replenishment, some patients with pheochromocytoma have intraoperative and postoperative complications. Hypotension is an important intraoperative complication due to decreased circulatory catecholamine levels following tumor removal. In addition, persistent preoperative alpha blockade results in decreased vascular tone. Intra- and postoperative hypotension usually responds well to normal saline bolus. Pressors may be required in patients who do not respond to intravenous fluids. Other complications include hypertensive crisis, hypoglycemia, and cardiac tachyarrhythmias.
(Choices 8 and C) Dopamine and dobutamine are less effective in those with pheochromocytoma and intraoperative hypotension as the majority of these patients are on preoperative long-acting alpha blockade. As a result, the vascular response to vasoconstrictors is reduced.
(Choice D) Studies have not shown that colloids are superior to crystalloid solution in the management of acute hypotension. In addition, colloids are more expensive than normal saline.
(Choice E) Intravenous infusion of phentolamine or sodium nitroprusside is preferred for managing intraoperative severe hypertension.
Educational objective: Intraoperative hypotension in patients with pheochromocytoma usually responds to an intravenous bolus of normal saline. Intravenous bolus of phentolamine is used for acute severe hypertension (not hypotension) during surgery for pheochromocytoma.