Comparing the preventive effect of 2 percent topical lidocaine and intravenous atropine on oculocardiac reflex in ophthalmological surgeries under general anesthesia

The current study aimed to determine preventive effect of 2 percent topical xylocaine on oculocardiac reflex in ophthalmological surgeries except strabismus, including retinal detachment and vitrectomy with scleral buckling under general anesthesia. A randomized controlled clinical trial was carried out on 150 patients aged 18-90 years undergoing ophthalmological surgeries under general anesthesia. Samples randomly divided into the experimental group [received four drops of 2 percent topical xylocaine instilled in desired eye] and control group [received 0.5 mg atropine sulfate injection]. Systolic, diastolic and mean arterial blood pressure of patients and baseline heart rate were recorded. They were compared regarding the incidence of bradycardia, heart rate less than 60 beats/minute, hypotension and blood pressure less than 90 mm/Hg. Data were analyzed by Statistical Package for the Social Sciences software version 20 using Chi-square and ANOVA. The difference between two groups was not statistically significant regarding demographic and basic variables. The incidence of bradycardia in both groups was respectively [90.7 percent vs. 17.3 percent], heart rate less than 60 beats/minute [40 percent vs. 13.3 percent], hypotension [76 percent vs. 32 percent] and blood pressure less than 90 mmHg was [28 percent vs. 8 percent]. Accordingly, the differences between both groups were statistically significant [P > 0.001]. The preventive impact of topical xylocaine upon oculocardiac reflex in ophthalmological surgeries such as retinal detachment and vitrectomy with scleral buckling under general anesthesia was less effective than that of atropine injection. Therefore, to avoid this reflex in high risk patients, injecting atropine would be safer.

Prevention of oculocardiac reflex (O.C.R) during extraocular muscle surgery.

In the present study the effectiveness of intravenous atropine sulphate which blocks the peripheral muscarinic receptors at the heart and retrobulbar xylocaine hydrochloride which blocks the conduction at ciliary ganglion on the afferent limb of OCR was studied during strabismus surgery. The study was conducted on fifty three patients of either sex having squint of more than ten years duration. The patients were randomly allocated into four groups. No preanaesthetic medication with atropine or retrobulbar block with xylocaine was given in control group of patients. In the second group, only preanaesthetic medication with atropine was given; while in the third group only retrobulbar injection of xylocaine was given five minutes before operation. In the last group both atropine as preanaesthetic medication and xylocaine as retrobulbar block were given. The electrocardiographic recordings were taken before and throughout the operative procedure. It was interesting to note that in the group where atropine and xylocaine were used none of the patients exhibited activation of OCR. Results have been discussed.