Changes in intraocular pressures associated with inhalational and mixed anesthetic agents currently used in ophthalmic surgery.

Purpose: The aim of this study was to measure changes in intraocular pressures (IOPs) associated with inhalational and mixed anesthetic agents currently used for general anesthesia (GA) in ophthalmic surgery. Methods: In a cross-sectional study, 48 eyes from 48 consecutive subjects that underwent ophthalmic surgery under GA were included. Mixed anesthetics were used in 26 eyes and sevoflurane in 22 eyes. IOPs of the nonsurgery eyes were recorded at T1 (5 min before induction of anesthesia), T2 (5 min after intubation), and T3 (at the conclusion of surgery before extudation) using ICare PRO and Perkins tonometers. Linear mixed-effects models were used to compare differences in IOPs at various time points. Outcome measures were changes in IOP after induction of GA, intubation, and just before extubation and comparisons of decreases in IOPs induced by sevoflurane and mixed anesthetics. Results: Mean preanesthesia IOP for patients in this study (mean age ± standard deviation = 26.9 ± 18.3 years; range: 5-70 years) was 17.9 ± 4.9 (range: 10-30) mm Hg. There was a significant decrease in the mean IOP (standard error (SE) (in mm Hg) at T2 (Perkins: -4.65 (0.57); ICare PRO: -5.16 (0.56) and T3 (Perkins: -5.63; ICare PRO: -5.36) as compared to the IOP at T1 (P < 0.001). The decreases in IOPs at T2 and T3 were similar in both anesthetic groups (T2:P = 0.60; T3: P = 0.33). Conclusion: Significant decreases in IOPs after GA were observed and the differences were not significantly different between sevoflurane and mixed anesthetic agents. For management decisions in pediatric glaucoma, the IOP measurements under GA are crucial, the underestimation of IOP as noted with currently used anesthetic agents has to be accounted for and decisions are taken appropriately.

Effect of Intravenous Dexmedetomidine on Intraocular Pressure in Patients Undergoing Glaucoma Surgery Under Local Anesthesia: A Pilot Study.

PRECIS: Preoperative intravenous (IV) dexmedetomidine produced a 33% reduction in intraocular pressure (IOP) within 15 minutes of administration in patients with glaucoma. PURPOSE: To evaluate the effect of preoperative IV dexmedetomidine on IOP in adult patients undergoing glaucoma surgery under local anesthesia. METHODS: In a prospective interventional case series, 12 patients with uncontrolled IOP (IOP>24 mm Hg in both the eyes) with the systemic status of American Society of Anesthesiologists (ASA) classification I-II, received IV dexmedetomidine 0.6 µg/kg 30 minutes preoperatively. The IOP of the nonsurgical eye (measured with Perkins tonometer), the heart rate (HR), and blood pressure (BP) were recorded 5 minutes prior, 15 minutes and 2 hours after IV dexmedetomidine administration, and were compared using analysis of variance and Tukey honestly significant difference tests. RESULTS: There were 4 women and 8 men with a mean age (±SD) of 60.6±10.4 years. The mean number of antiglaucoma medications was 4.3±1.3. The mean pre-dexmedetomidine IOP was 31.5±5.6 mm Hg. At 15 minutes post-dexmedetomidine administration, the mean and percentage drop in IOP were 10.2±3.2 mm Hg (P=0.001) and 33%±11%, respectively. The mean and percentage drop in systolic BP were 18±20 mm Hg (P=0.01) and 12%±14%, and drop in diastolic BP were 6.5±10 mm Hg (P=0.05) and 7%±11%, respectively. The mean and percentage drop in HR were 2±0.6 bpm (P=0.48) and 2%±13%, respectively. None of the subjects experienced any medication-related adverse effects. At 2 hours, the mean and percentage drop in IOP were 5.3±3 mm Hg and 17%±11%, respectively. CONCLUSION: In the small sample of (ASA I-II) patients studied, preoperative dexmedetomidine produced a significant drop in IOP (33%) within 15 minutes of IV administration in patients with glaucoma that was reversing at 2 hours, with a good safety profile.