Bi-spectral index guided closed-loop anaesthesia delivery system (CLADS™) in pheochromocytoma

Abstract

Anaesthetic management of pheochromocytoma is far from satisfactory even though various techniques are available. Feasibility as well as safety of Bi-spectral Index (BIS)-guided closed-loop control of anaesthesia has been shown in various clinical settings. We evaluated the performance of BIS-guided closed-loop-anaesthesia-delivery system (CLADS) in patients undergoing resection of pheochromocytoma. Thirteen patients (7 males and 6 females, 15-65 years) who underwent adrenalectomy for pheochromocytoma in the past 4 years operated by a single surgeon were included in the study. Closed-loop-control of propofol-anaesthesia was induced and maintained with target BIS value =50. Median performance error and median absolute performance error of target BIS control were 2 (2-7) [median (IQR)] and 10 (8-10), respectively. BIS was maintained within 50 +/- 10 for 87 +/- 8.6% (mean +/- SD) of the valid CLAD time. Heart rate (HR) and mean arterial pressure (MAP) were maintained within +/-25% of the baseline value for 90.3 +/- 12.1% and 76.3 +/- 13.2% of the time duration, respectively. BIS increased significantly following intubation, incision and tumor handling (P = 0.001, 0.001 and 0.03 respectively). There was a significant fall in both HR and MAP following induction of anaesthesia (P = 0.001), and MAP following tumor excision (P = 0.045) as compared to the baseline. Though maximum HR within 5 min post-intubation, post-incision and during tumor handling were significantly higher (P = 0.001, 0.014 and 0.037) compared to just before the respective event, they were not statistically different from the baseline. Though maximum MAP within 5 min post-intubation, post-incision and during tumor handling were significantly higher compared to MAP just before the respective event (P = 0.001, 0.021 and 0.001), they were not significantly different compared to the baseline value except maximum MAP during tumor handling (P = 0.001). CLADS performed well in patients undergoing pheochromocytoma surgeries which represent one of the few clinically extreme situations.