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Abstract #25375 Published in IGR 12-1
Intraoperative changes in intraocular pressure under sevoflurane and propofol anesthesia during spinal surgery in prone position
Hayashi H; Kawaguchi M; Hasuwa K; Kurita N; Inoue S; Furuya HJournal of Neurosurgical-Anesthesiology 2009; 21: 418
Postoperative visual loss (POVL) following spinal surgery in prone position is a rare but devastating. The reported incidence ranges from 0.03% to 0.2%.(1) Although a number of intraoperative factors have been implicated, exact etiology remains undetermined. Increasing intraocular pressure (IOP) caused by prone positioning has been recognized as one of important risk factors for POVL. Increased IOP can cause low perfusion pressure of the optic nerve head, resulting in POVL. The purpose of this study is to investigate intraoperative change of IOP under sevoflurane and propofol anesthesia during spinal surgery in prone position. Method: After institutional approval and written informed consent were obtained, 21 patients undergoing elective spinal surgery in prone position under general anesthesia were enrolled in this study. There were no patients with preoperative glaucoma. Patients were randomly allocated to one of two groups according to anesthetic agents used for maintenance of anesthesia; sevoflurane group (n=11) and propofol group (n= 10). Bilateral IOPs were intraoperatively measured using the Tonopen handheld tonometer (Tonopen XL, BIO RAD, Osaka). Measurements were performed at the following 5 points; (1) after the induction of anesthesia in supine position (baseline), (2) 5 minutes after postural change to prone position, (3) 60 minutes after prone position, (4) 120 minutes after prone position, and (5) 5 minutes after postural change to supine position at the end of operation. Result: There were no significant differences in demographic variables between the two groups. In both groups, a significant increase in IOP was observed at the beginning of prone position and continued until 5 minutes after postural change to supine position. IOP peaked at 120 minutes after prone position with mean IOP values of 25 and 22mm Hg (11 and 8mm Hg at baseline) in sevoflurane and propofol group, respectively. There were no significant differences in IOP and %changes of IOP between the two groups. No patients had ophthalmological complication after spinal surgery in both groups. Conclusion: IOP significantly increased when patients were placed in prone position under sevoflurane and propofol anesthesia. The increase of IOP during prone positioning for a relatively short period was comparable between sevoflurane and propofol anesthesia.
H. Hayashi. Department of Anesthesiology, Nara Medical University, .
Classification:
12.17 Anesthesia (Part of: 12 Surgical treatment)
6.1.3 Factors affecting IOP (Part of: 6 Clinical examination methods > 6.1 Intraocular pressure measurement; factors affecting IOP)
