comparison of intravenous lidocaine versus hyoscine on prevention of oculocardiac reflex in strabismus surgery

purpose: oculocardiac reflex (ocr) is a frequent event during strabismus surgery. the aim of this study is to compare the preventive effect of intravenous lidocaine and hyoscine on ocr.methods: this prospective, randomized clinical trial was performed on 75 patients (5-63 years old) underwent strabismus surgery. patients divided randomly into three groups. intravenous hyoscine (0.2 mg/kg), lidocaine (1.5 mg/kg) and distilled water were injected before induction with propofol for each group respectively under standard monitoring. heart rate, blood pressure and/or cardiac dysrrythmia were recorded immediately before/after injection and muscle hooking. decrease of heart rate more than 20%, hypotension (decrease more than 20% in systolic or diastolic pressure) or any cardiac dysrrythmia were defined as ocr. results: one hundred and thirty-six muscles were hooked during strabismus surgery. ocr was observed in 44 hooked muscles (32.3%). reflex was observed in hyoscine (34.2%), lidocaine (24.9%) and control (40.9%) groups (p=0.12). the most stretched muscles which caused ocr were medial rectus (56.8%) and lateral rectus (36.3%) muscles. ocr was greater in patients with age between 5-10 years (56%). conclusion: intravenous lidocaine and n-buthylbromide hyoscine both could reduce ocr occurrence but the difference was not statistically significant compared to the control group. ocr was seen greater in young patients (5-10 years old). some patients (specially children) need intervention to restore normal condition.   iranian journal of ophthalmology 201426(4):217-22 © 2014 by the iranian society of ophthalmology