The Oculocardiac Reflex: A Review

Abstract

Background A typical oculocardiac reflex (OCR) is a moderate trigemino-vagal bradycardia elicited by tension on an extraocular muscle (EOM) during strabismus surgery; however, many other orbital stimuli can elicit cardiac slowing including retinopathy of prematurity examination. Methods World literature related to trigeminovagal and oculocardiac reflex covering over 15,000 patients including 51 randomized clinical trials and case reports are analyzed and reviewed. Under an ongoing observational trial in Alaska, anesthetic, patient and surgical influences on routine strabismus surgery using prospective, uniform EOM tension are compared seeking sufficient sample size to characterize this individually widely variable cardiac response. Results With adequate sample size, and emphasizing clinical studies controlling type of EOM, muscle tension amount and duration, anticholinergic and opioid medications, the following augment OCR; rapid-acting opioids and dexmedetomidine while OCR is reduced in older patients, the right eye, less EOM tension, deeper inhaled agents, hypocarbia, anticholinergic medications and orbital block. In re-operations, the former are relatively poor predictors of subsequent OCR. Conclusion Profound bradycardia can occur in almost 10% of strabismus surgery cases without anticholinergic preventive measures, but reliable prediction of OCR remains elusive. With foreknowledge and careful anesthetic monitoring of the patient before EOM manipulation, residual adverse sequelae from OCR are fortunately very rare. Despite well over a century of experience, the teleology for this occasionally dramatic cardiac response to eye surgery is still not known.

Prediction of the Occurrence of the Oculocardiac Reflex Based on the Assessment of Heart Rate Variability. An Observational Study

“…According to a literature review by Arnold [31], the oculocardiac reflex may not be consistently predictable or preventable in a population of children with strabismus. Based on our results, which revealed no correlation between the incidence of OCR and several pre-phenomenon measures, the same statement can be applied to adult patients undergoing episcleral buckling as a treatment for retinal detachment.…”

“…NIBP measurement was started at the moment of traction, but the manoeuvre did not last long, so it is possible that it was not long enough to record the precise blood pressure value. However, NIBP is the standard method for intraoperative blood pressure monitoring, and the realtime blood pressure during OCR has only rarely been documented [31,39]. It is important to note that the OCR is defined as a change in chart rate, not blood pressure; therefore, this limitation should not be considered very important.…”

Restrictive strabismus and gaze-evoked oculocardiac reflex following pterygium repair with fibrin glue

“…Typically, bradycardia OCR is triggered by quick traction on extraocular muscles even with minimal force. 6 However, this is not unique to the muscles, as cases of OCR upon conjunctival traction, dissection, and closure have been reported. 7 We believe that previous scarring, and its location on top of the medial rectus, played a major role in this outcome.…”

Considerations for Corneal Surgery With Patients in the 10th Decade of Life

“…Although it has a rare incidence, it is a well-documented cause of asymptomatic bradycardia in ophthalmic surgery, believed to be induced by mechanical manipulation of the eye, and it can be augmented by the use of fast-acting opioids, such as fentanyl. 51 If not treated promptly, it can lead to complications such as cardiac arrest. 51 A well-planned surgical procedure and careful considerations with anesthesia can avoid these complications.…”