The Effects of Furosemide and Hypoxia on CIick-Evoked Otoacoustic Emissions in Anesthetized Guinea Pigs

Abstract

From the concepts of well known ototoxic effects of loop diuretics and hypoxic state, twenty anesthetized guinea pigs with diuretics and/or hypoxia were evaluated with click-evoked otoacoustic emissions (CEOAEs) by timesequential monitoring. Furosemide 25 mg/kg was infused intravenously and CEOAEs were measured before and 5, 10, 20, 30, 45 and 60 minutes after injection in 8 guinea pigs. Both echo responses and reproducibilities were decreased significantly at 10 minutes after injection and showed minimal level at 20 minutes. Recovery of CEOAEs was noted by spectral analysis at 30 minutes after injection, and full recovery of CEOAEs was evident after then. At 60 minutes after injection, hypoxia of 20 seconds by turning off the artificial respirator was added. The CEOAEs showed statistically significant decreases compared with those of prehypoxic state (p<O.OI). The CEOAEs of 8 guinea pigs with injection of furosemide. 50 mg/kg showed decreased responses and no fr recoveries for the 60 minutes observation periods. Findings from this study support the clinical utility of CEOAEs as a screening test for early detection of various ototoxicities.