Background:  OCR commonly occurs during strabismus surgery, producing bradycardia, arrhythmias and even cardiac arrest after manipulation of orbital structures. Ketamine is NMDA receptor antagonist and acts as an analgesic.

Aim: To determine the effect of ketamine premedication on prevention of OCR during strabismus surgery.

Study design:  Randomized control trial

Methodology:  60 patients were randomly divided into two groups i.e., Ketamine 0.75mg/kg (Group K) and control (Group C). Group K patients were premedicated with 0.75mg/kg ketamine while Group C patients did not receive any premedication. Heart rate and ECG were observed 30 sec before and continuously after traction on extraocular muscles was applied upto end of surgery for bradycardia and arrhythmias. Percentage change in HR and presence of arrhythmias was documented. All the data was collected using case report form and analyzed using SPSS version 15.

Results: In Group C, 15(50%) cases had arrhythmias while in Group K, only 4(13.33%) cases had arrhythmias. Mean HR in Group C was 118.77±6.92/min and in Group K was 101.57±15.65/min. In Group C, oculocardiac reflex was present in 23(76.7%) cases and in Group K, OCR was present in 6 (20%) cases and prevented in 24 (80%) cases.

Conclusion:  Premedication with 0.75mg/kg IV ketamine significantly reduces the occurrence of oculocardiac reflex during strabismus surgery.

Keywords:  Ketamine, Oculocardiac Reflex, Premedication, Prevention, Strabismus