Oculocardiac reflex: pathophysiology and case report

The Oculocardiac Reflex: A Review

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.

Oculocardiac reflex in an adult with a trapdoor orbital floor fracture: case report, literature review, and differential diagnosis

Orbital floor blowout fractures can result in a variety of signs and symptoms depending on the severity of the bone defect. Large defects often result in enophthalmos and restriction of ocular movement; yet the timing of surgery can be delayed up to two weeks with good functional outcomes. In contrast, an orbital trapdoor defect with entrapment of the inferior rectus muscle usually elicits pain with marked restriction of the upward gaze and activation of the oculocardiac reflex without significant dystopia or enophthalmos. When autonomic cardiac derangement is diagnosed along with an orbital floor fracture, it has been suggested that the fracture should be treated immediately. Otherwise, it will result in continued hemodynamic instability and muscular injury and may require a second surgery. This article reports the management of an unusual presentation of a trapdoor blowout orbital floor fracture surgery with oculocardiac response in an adult, with emphasis on its pathophysiology, management, and differential diagnosis.

Trigemino-cardiac reflex during orbital floor reconstruction: a case report and review

Trigemino-cardiac reflex is occurrence of hypotension and bradycardia upon surgical manipulation of areas supplied by the trigeminal nerve, and has been reported during craniofacial maxillofacial and ocular surgeries. Communication between the anaesthetic and surgical team is essential, and cessation of the precipitating stimulus is the first and most important therapeutic step. We report a case of immediate, reproducible, and reflexive response of Bradycardia and dysrhythmia upon manipulation of orbital fracture during orbital floor reconstruction in a 65-year-old man. Upon recognition of the reproducible relationship between falcine stimulation and increased vagal tone, the patient was given atropine in an effort to block cholinergic hyperactivity. After atropine administration, no further dysrhythmias occurred and surgery was carried uneventfully.

Delayed trigeminocardiac reflex induced by an intraorbital foreign body. Case report

OBJECTIVE

To emphasize the importance of the mechanism and surgical approach to trigeminocardiac reflex (TCR) developing 48 h after orbital trauma due to a foreign body.

CASE REPORT

After gunshot injury of a 17-year-old male patient, computerized tomography evaluation revealed a right globe perforation and an intraorbital metallic foreign body in the right orbita adjacent to the lateral wall. The ocular perforation was repaired, but the foreign body was not removed. Constant bradycardia (45/min) developed 48 h after the operation. Since there were no cardiological findings, a temporary cardiac pacemaker was inserted and on the 6th postoperative day, the foreign body was removed through orbitolateral approach. After the removal of the foreign body, bradycardia completely recovered.

CONCLUSION

In the presence of an intraorbital foreign body accompanied by globe perforation, TCR may develop 48 h after the trauma and insertion of a temporary pacemaker may be required to control the cardiac rhythm. In this paper, the delayed TCR complication presented an indication for the removal of the intraorbital foreign body.

Pediatric orbital floor fractures: Nausea/vomiting as signs of entrapment

OBJECTIVE: We sought to explore whether nausea and vomiting are predictive of entrapment.

STUDY DESIGN AND SETTING: We retrospectively evaluated the data regarding orbital floor fractures in children younger than 19 years old presenting at a tertiary care center from 1990 to 2001. Zygomatic, naso-orbital ethmoid, and displaced orbital rim fractures were excluded from our analysis. Data on the fracture type, signs and symptoms, ocular motility, surgical repair, and resolution of diplopia were also collected.

RESULTS: Twenty-nine orbital floor fractures were identified. One fourth of the children had nausea/ vomiting, and half had trapdoor fractures. Seventeen percent of patients had entrapment of the inferior rectus. The positive predictive value of nausea/vomiting with a trapdoor fracture for entrapment was 83.3% ( P = 0.002, Fisher exact test). Half the patients required surgical intervention, most commonly for diplopia or gaze restriction. Gaze impairment did not resolve in 2 patients.

CONCLUSION: Patients with trapdoor fractures who present with nausea/vomiting are at a high risk of inferior rectus entrapment and poor outcome. (Otolaryngol Head Neck Surg 21003;129:000-000)

The intraoperative oculocardiac reflex as a predictor of postoperative vaso-vagal responses during adjustable suture surgery

Adjustable suture surgery has become a popular method of strabismus correction in those cases in which results are less predictable, such as reoperations, thyroid ophthalmopathy, and blind eyes. Complications related to adjustable strabismus surgery are, in general, no different than those related to standard surgical techniques. We noticed a subgroup of patients who experienced significant vaso-vagal responses (V-VR) during postoperative adjustment and sought to discover a method of identifying these patients prior to adjustment. Sixty patients were studied prospectively from July 1991 to July 1992. All patients had surgery under general anesthesia and were adjusted 24 hours later. A positive oculocardiac reflex (OCR) occurred when a 10% or greater intraoperative change in heart rate was associated with traction on an extraocular muscle. A positive V-VR postoperatively consisted of one or more subjective findings (dizziness, light-headedness, nausea, or body temperature changes), and two or more objective findings (10% or greater change in heart rate, hypotension, pallor, diaphoresis, vomiting, disorientation, or loss of consciousness). Variables studied for predictive value included OCR, age, sex, strabismus type, previous surgery, muscle adjusted, and systemic disease. Twenty-five patients (41.6%) had a positive V-VR during adjustment. Twenty-seven patients (45%) had a positive OCR. Eighty-five percent of patients with a positive OCR and 9% of patients with a negative OCR had a positive V-VR. Younger patients were also more likely to have a positive V-VR. A positive intraoperative OCR under general anesthesia during strabismus surgery is highly predictive of a postoperative V-VR during planned adjustment.