Effects Of Intravenous Administration Of Dexme-Detomidine On Intraocular Pressure In Rabbits

Objectiveto observe the effect of intravenous different dose of α2-adrenoreceptor (α2AR) dexmedetomidine (DEX) on intraocular pressure (IOP)、pupil size (PS)、blood pressure (BP)、heart rate (HR) and respiration rate (RR) in rabbits.Methods30Japanese big ear rabbits were randomly divided into three groups(n=10in each group):DEX3μg/kg (group S)、9μg/kg (group M)、27μg/kg (group L). Three groups of drugs diluted in normal saline respectively for10ml were infusioned constantly for10min through the rabbit ear margin vein. To fix the rabbits in supine position,drop1～2drops of alcaine to ocular surface for topical anesthesia,drop two times at the time interval of3～5minutes,drop1drop at the time interval of30minutes during the experiment. Measure the IOP、PS of two eyes at basic value when the BP and RR of rabbits restore calm.To measure IOP at premedication and every30min after giving medicine for300min, the IOP value is the average of measured three times, two eyes measuring alternately, begin with the right eye. To measure PS at premedication、after giving medicine and every10min after giving medicine for60min. To measure BP、HR and RR at premedication after giving medicine and every10min after giving medicine for returning to basic value.ResultsThe IOP and PS between two eyes in rabbits is not statistical difference in the same dose of DEX (P>0.05). In group S, The IOP of right eye and left eye respectively decreased to minimum value14.19±0.40mmHg、14.21±0.44mmHg from basic value15.48±0.27mmHg、15.58±0.26mmHg at60min, having significantly statistical difference(P<0.05),returned to basic value at120min.compared with group S,The IOP of right eye and left eye of group M respectively decreased to minimum value11.21±0.35mmHg、11.25±0.42mmHg at90min, returned to basic value at240min, having significantly statistical difference(P<0.05). Compared with group M,The IOP of right eye and left eye of group L respectively decreased to minimum value9.54±0.30mmHg、9.60±0.43mmHg at60min, returned to12.99±0.34mmHg、13.05±0.47mmHg at300min, having significantly statistical difference (P<0.05). In group S, The PS of right eye and left eye respectively decreased to minimum value6.53±0.62mm、6.48±0.58mm from basic valeue7.10±0.62mm、6.80±0.76mm at10min, having no statistical difference (P>0.05). Compared with group S, The PS of right eye and left eye of group M respectively decreased to minimum value5.25±0.8mm0、5.29±0.87mm at lOmin, having significantly statistical difference (P<0.05).Compared with group M, The PS of right eye and left eye of group L respectively decreased to minimum value5.01±0.62mn、4.96±0.57mm at10min, having no statistical difference (P>0.05). The PS of group M and group L respectively returned to basic value at30min、60min. compared with group M, the blood pressure、heart rate and respiration rate of group L was significantly decreased (P<0.05), compared with group S, the blood pressure、heart rate and respiration rate of group M was significantly decreased (P<0.05).the time of blood pressure decreasing of group L was longer than group M,the time of blood pressure decreasing of group M was longer than group S(P<0.05).The time of heart rate decreasing of group M was longer than group S,compared with group M, the time of heart rate decreasing of group L is not significantly diferent (P>0.05).the time of respiration rate decreasing of group L was longer than group M,the time of respiration rate decreasing of group M was longer than group S (P<0.05).ConclusionThe degree and time of intraocular pressure decreasing is suitable in9μg/kg DEX, and no obvious respiratory inhibition, blood pressure and heart rate has no obvious decrease. but it can make pupil miosis, it must be used in combination with mydriatics in ophthalmic surgical which require complete dilation of the pupil.