Oculocardiac Reflex During Peribulbar Block: Importance of Early Monitoring

A case report published in Cureus has highlighted the clinical importance of patient monitoring during regional anesthesia to ensure the early recognition of the oculocardiac reflex (OCR). The report details the experience of a 64-year-old woman with no known comorbidities who developed sudden bradycardia while undergoing a peribulbar block.

The oculocardiac reflex, also known as the Aschner reflex or the trigeminovagal reflex, is a recognized autonomic phenomenon. It is characterized by a reduction in heart rate that occurs in response to the stimulation of ocular structures.

Physiology and Identification of the Reflex

First described in 1908, the OCR involves a physiological response where stimulation of the eye or surrounding tissues triggers a decrease in heart rate. According to data from ScienceDirect, the reflex is formally defined as a decrease in heart rate that is greater than 20% of the patient’s baseline.

Several specific triggers can induce this response, including:

• Applied pressure to the globe of the eye.
• Traction of the extraocular muscles (EOM).
• Stimulation of other orbital structures.

Clinical Occurrences and Risks

Medical literature indicates that the oculocardiac reflex is most frequently encountered during strabismus surgery. However, the Cureus case study demonstrates that the reflex can also manifest during regional anesthesia techniques, such as a peribulbar block.

In the reported case, the 64-year-old patient experienced sudden bradycardia during the administration of the block, despite having no prior medical conditions that would typically predispose a patient to such an event.

The Importance of Early Recognition

The case report emphasizes that monitoring is essential for the early recognition of the oculocardiac reflex. Because the reflex can cause a sudden drop in heart rate, continuous monitoring allows medical providers to identify the onset of bradycardia immediately and take necessary action to maintain patient stability during ocular procedures.