Demographic and surgical factors affecting the oculocardiac reflex during strabismus surgery

PURPOSE: Determination of demographic and surgical factors affecting oculocardiac reflex (OCR) in strabismus surgery.
METHODS: 38 patients were included in the study. 74 muscles were operated. Horizontal muscle recession or resection, inferior oblique (IO) muscle recession surgery were performed. Patient’s age, gender, heart rate (HR) at the beginning of surgery, surgery duration, presence of OCR, number of muscles, and muscle type were recorded. A 20% decrease in HR during muscle traction constituted the patient group with OCR.
RESULTS: : 43 medial rectus (MR), 19 lateral rectus (LR), 9 IO, 2 superior rectus, and 1 inferior rectus muscle surgeries were performed. OCR occurred in 20 (52.6%) patients. When the OCR and non-OCR groups were compared, no significant differences were found in terms of age, gender, surgery duration, and HR. The mean number of operated muscles in patients with OCR was 2.15±0.87 muscles, and in patients without OCR, it was 1.72±0.46 muscles (p=0.72). 4 (20%) of the patients with OCR had undergone single muscle surgery, 8 (40%) had undergone 2 muscle surgeries in the same eye, and 8 (40%) had undergone bilateral surgery (p=0.70). In the OCR group, there were 14 (32.6%) MR, 4 (21.1%) LR, and 7 (75%) IO, and the difference was due to IO (p=0.024). OCR occurred in 18 (40%) muscles in horizontal muscle recession, 2 (10.5%) in resection, and 7 (75%) in IO recession (p=0.02), and the difference was due to IO recession. When muscle traction was released, OCR returned to normal in all patients.
CONCLUSION: OCR is a life-threatening process that may have complications such as bradycardia and asystole. We think that OCR will be frequently encountered during IO surgery and that the surgery should be performed with low traction.