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Abstract #10808 Published in IGR 6-2
Effect of acetazolamide on the optic disc oxygenation in miniature pigs
Petropoulos IK; Pournaras JA; Munoz JL; Pournaras CJKlinische Monatsblätter für Augenheilkunde 2004; 221:367-70
BACKGROUND: The purpose of our study was to evaluate the variations of the optic disc PO (2) during normoxia and hyperoxia (100 % O2), before and after intravenous administration of acetazolamide. MATERIAL AND METHODS: PO2 measurements were obtained at intervascular areas of the optic disc in 11 anaesthetized miniature pigs using oxygen-sensitive microelectrodes introduced through the vitreous cavity by a micromanipulator. PO2 was measured continuously during 10 minutes under systemic normoxia and systemic hyperoxia. Oxygen measurements were repeated under these conditions after intravenous injection of acetazolamide (bolus of 500 mg) in 8 animals. RESULTS: In systemic hyperoxia, the optic disc PO2 increased moderately (δPO2 = 4.7 ± 2.5 mmHg; p < 0.001; n = 11) in parallel with systemic PaO (2). Acetazolamide led to a slow and progressive increase in the optic disc PO (2) (δPO2 = 2.1 ± 1.7 mmHg; p > 0.1; n = 8 after 10 min, while δPO2 = 4.3 ± 3.2 mmHg; p < 0.05; n = 8 after 30 min), in parallel with a slow and progressive increase in systemic PaCO2. The optic disc PO2 increased much more significantly after injection of acetazolamide under systemic hyperoxia (δPO2 = 13.3 ± 3.1 mmHg; p < 0.001; n = 8). CONCLUSIONS: Systemic hyperoxia alone is not sufficient to increase substantially the optic disc PO2 in miniature pigs due to a vasoconstrictor effect. Intravenous injection of acetazolamide can increase the optic disc PO2 progressively, due to a vasodilatory effect of elevated systemic PaCO 2. The association of acetazolamide injection with systemic hyperoxia can further improve the oxygenation of the optic disc. LA: German
Department of Ophthalmology, University Hospitals of Geneva, Geneva, Switzerland.
Classification:
11.5.1 Systemic (Part of: 11 Medical treatment > 11.5 Carbonic anhydrase inhibitors)