Predictors of hemodynamic instability during surgery for pheochromocytoma.

BACKGROUND: Resection of pheochromocytoma is often associated with hemodynamic instability (HDI). We examined patient and tumor factors that may influence HDI. The effect of pretreatment with nonselective α blockade phenoxybenzamine (PXB) versus selective α blockade on HDI and outcomes was also evaluated.
METHODS: The records of 91 patients who underwent adrenalectomy between 2002 and 2013 were retrospectively reviewed. HDI was determined by number of intraoperative episodes of systolic blood pressure (SBP) > 200 mmHg, those greater than or less than 30 % of baseline, heart rate > 110 bpm, and the need for postoperative vasopressors. Fishers exact, t test and regressions were performed.
RESULTS: Among 91 patients, 78 % received PXB, 18 % selective α blockade and 4 % no adrenergic blockade. Patient demographics, tumor factors and surgical approach were similar among the blockade groups. On multivariate analysis, increasing tumor size was associated with a significant rise in the number of episodes of SBP > 30 % [rate ratio (RR) 1.40] and an increased postoperative vasopressor requirement [odds ratio (OR) 1.23]. Open adrenalectomy and use of selective blockade were associated with an increased number of episodes of SBP > 200 mmHg (RR 27.8 and RR 20.9, respectively). Open adrenalectomy was also associated with increased readmissions (OR 12.3), complications (OR 5.6), use of postoperative vasopressors (OR 4.4) and hospital stay (4.6 days longer). There were no differences in other HDI measurements or postoperative outcomes among the blockade groups.
CONCLUSIONS: Tumor size, open adrenalectomy, and type of α blockade were associated with intraoperative HDI during pheochromocytoma resection. Selective blockade was associated with significantly more episodes of intraoperative hypertension but no perioperative adverse outcomes.