Oculocardiac Reflex during Strabismus Surgery

Purpose: To investigate the factors that influence development of oculocardiac reflex (OCR) during strabismus surgery and to discuss the preventive strategies. Methods: We examined patients undergoing surgery for strabismus. One hundred and sixty extraocular muscles of 73 patients were operated and 114 extraocular muscles of 50 patients who were operated under general anesthesia were evaluated. We investigated the incidence of the OCR and subsequent postoperative vaso-vagal response (VVR). Results: An overall rate of 74.0% of the patients and 53.8% of the muscles showed a positive OCR. Under general anesthesia, 74.0% of the patients and 50.9% of the muscles showed a positive OCR. There was a significant difference in the frequency of OCR between the medial rectus and the other muscles (p=0.009). The development of OCR is frequent during muscle traction in strabismus surgery. There was a significant association between positive OCR and subsequent postoperative VVR (p=0.039). Conclusions: The predictive factors of the OCR during strabismus surgery under general anesthesia were muscle type and procedure. Therefore cardiac monitoring during the operation is needed and gentle manipulation of the extraocular muscles is important especially when the medial rectus muscle. The estimation of OCR will be helpful for prevention of subsequent postoperative VVR.