Intravenous methylene blue as an aid to intraoperative localization and removal of the adrenal glands during laparoscopic adrenalectomy

Background We hypothesized that intravenous methylene blue will facilitate adrenal gland identification and resection during laparoscopic adrenalectomy. Methods Five mini-Hanford pigs were anesthetized and monitored per an approved Internal Review Board protocol. Timing of color changes in the adrenals was recorded after administering methylene blue at three different doses: 2.5 mg/kg, 5.0 mg/kg, and 7.5 mg/kg. The time required for laparoscopic adrenalectomy with and without methylene blue was recorded. Results No color change occurred after the 2.5 mg/kg dose. For the 7.5 mg/kg versus the 5.0 mg/kg dose there was a more rapid bluish color change (mean time, 1.89 minutes versus 3.45 minutes; P = 0.03) and a longer duration of bluish color change (mean time, 12.20 minutes versus 6.19 minutes; P = 0.01). Laparoscopic adrenalectomy using methylene blue resulted in a 34.5% faster median resection time (10.13 minutes versus 15.47 minutes). Conclusions Methylene blue concentrates in the adrenal glands and facilitates identification and resection of the adrenal glands by a laparoscopic approach.