Oculocardiac reflex during retinal surgery using peribulbar block and nitrous narcotic anesthesia

BACKGROUND AND OBJECTIVES: This study was designed to examine the effects of local and general anesthesia on the oculocardiac reflex (OCR) in adults during retinal detachment surgery, with an aim of determining the safest type of anesthesia and on which extraocular muscle traction causes a higher incidence of OCR. PATIENTS AND METHODS: The study was performed on 30 American Society of Anesthesiologists-I patients (age range 40-60 years) who were undergoing retinal detachment surgery. Fifteen patients underwent surgery with general anesthesia and 15 were given a local peribulbar block. A fixed traction of 400 g was applied to all the extraocular muscles, and the heart rate, rhythm, and electrocardiogram of each patient was monitored. RESULTS: The overall incidence of OCR was higher with general anesthesia (63.3%) than with local anesthesia (14.4%). There was a significant decrease in heart rate for the rectus muscles (P<.0005) as well as the oblique muscles (P<.005) during traction with general anesthesia. All four rectus muscles were equally sensitive in eliciting the reflex. The incidence of dysrhythmias was 20% with general anesthesia and 6.67% with local anesthesia. CONCLUSION: This study showed that local anesthesia produces less bradycardia and ectopic arrhythmias and, therefore, may be safer and better than general anesthesia for surgeries in which traction of extraocular muscles is required.