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Abstract #27318 Published in IGR 12-4
The effect of the alpha-2 agonist brimonidine on intraocular pressure during prone spine surgery
Farag E; Wang L; Yang D; Kalfas I; Cata J; Kurz AJournal of Neurosurgical-Anesthesiology 2010; 22: 404
Introduction: Vision loss after spine surgery is a devastating problem,(1) which results from impaired perfusion of the eye or occlusion of retinal vessels due to increased intraocular pressure (IOP). The topical (alpha)2- agonist brimonidine has been used successfully as monotherapy for glaucoma to decrease IOP.(2) Alpha-2 agonists also have a neuroprotective effect on retinal ganglion cells. We therefore tested the hypothesis that brimonidine drops limit the increase in IOP that normally accompanies prolonged prone spine surgery. Methods: Sixty-five patients were randomized to 1 drop per eye of brimonidine or placebo. Drops were given 1 hour before induction of anesthesia and thereafter every 8 hours during surgery. Patients were simultaneously randomized to receive either crystalloid or colloid fluid replacement. Anesthesia was standardized. IOP was measured with a pneumatonometer before induction of anesthesia, after induction in supine position, every 30 minutes in the prone position, and during recovery. The primary outcome was time-weighted IOP, and was assessed by analysis of covariance. Results: The randomized groups were well balanced at baseline. IOP in the brimonidine patients was significantly, 4.2 (95% confidence interval: 7.8, 0.57) mm Hg, less than in the placebo patients (P=0.024, Fig. 1). Brimonidone did not affect change from baseline IOP (P=0.058) or the fraction of patients with IOP >50mm Hg (P=0.80). Discussion: The increase in IOP during prone spine surgery was substantial, and maximum IOP exceeded 50mm Hg in about a fifth of the patients. The (alpha)2 agonist brimonidine significantly reduced intraoperative IOP. However, the reduction was small and unlikely to be clinically important. Furthermore, the fraction of patients developing IOP >50mm Hg was similar in each group. Topical brimonidine thus does not appear to be a clinically useful way of preventing increased IOP during prolonged prone spine surgery.
E. Farag. Cleveland Clinic, United States.
Classification:
11.3.3 Apraclonidine, brimonidine (Part of: 11 Medical treatment > 11.3 Adrenergic drugs)
9.4.15 Glaucoma in relation to systemic disease (Part of: 9 Clinical forms of glaucomas > 9.4 Glaucomas associated with other ocular and systemic disorders)
