More hypotension in patients taking antihypertensives preoperatively during shoulder surgery in the beach chair position.

PURPOSE: Hypotension is common in patients undergoing surgery in the sitting position under general anesthesia, and the risk may be exacerbated by the use of antihypertensive drugs taken preoperatively. The purpose of this study was to compare hypotensive episodes in patients taking antihypertensive medications with normotensive patients during shoulder surgery in the beach chair position. METHODS: Medical records of all patients undergoing shoulder arthroscopy during a 44-month period were reviewed retrospectively. The primary endpoint was the number of moderate hypotensive episodes (systolic blood pressure ≤ 85 mmHg) during the intraoperative period. Secondary endpoints included the frequency of vasopressor administration, total dose of vasopressors, and fluid administered. Values are expressed as mean (standard deviation). RESULTS: Of 384 patients who underwent shoulder surgery, 185 patients were taking no antihypertensive medication, and 199 were on at least one antihypertensive drug. The antihypertensive medication group had more intraoperative hypotensive episodes [1.7 (2.2) vs 1.2 (1.8); P = 0.01] and vasopressor administrations. Total dose of vasopressors and volume of fluids administered were similar between groups. The timing of the administration of angiotensin-converting enzyme inhibitors and of angiotensin receptor antagonists (≤ 10 hr vs > 10 hr before surgery) had no impact on intraoperative hypotension. CONCLUSIONS: Preoperative use of antihypertensive medication was associated with an increased incidence of intraoperative hypotension. Compared with normotensive patients, patients taking antihypertensive drugs preoperatively are expected to require vasopressors more often to maintain normal blood pressure.