What causes Oculocardiac reflex?

Oculocardiac Reflex (Fig. The oculocardiac reflex (OCR) is a reflex resulting in severe bradycardia caused by traction applied to the extraocular muscles (especially the medial rectus muscle), pressure on the globe, ocular trauma, traction on the conjunctiva, or occasionally by placement of a retrobulbar block.

What is trigeminal cardiac reflex?

The trigemino-cardiac reflex (TCR) is defined as the sudden onset of parasympathetic dysrhythmia, sympathetic hypotension, apnea or gastric hypermotility during stimulation of any of the sensory branches of the trigeminal nerve.

Which cranial nerve is bradycardia?

trigeminal nerve
The trigeminocardiac reflex (TCR) manifests as bradycardia or asystole with hypotension when any branch of the trigeminal nerve is stimulated [1].

Is Oculocardiac reflex normal?

Incidence of the OCR varies widely in literature depending on the clinical conditions. Two studies reported the incidence of the OCR during strabismus surgery as 56% and 68%, while rates were lower in facial surgery (specifically an orbitozygomatic approach), where the rate was 31.7%.

Does atropine block vagal response?

Atropine works by blocking peripheral muscarinic receptors of the heart and causes increased firing at the sinoatrial node as well as conduction through the AV node. This opposes the vagal response, or the efferent limb, of the OCR.

Is jaw jerk reflex normal?

Normally this reflex is absent or very slight. However, in individuals with upper motor neuron lesions the jaw jerk reflex can be quite pronounced.

Does vagus nerve affect blood pressure?

Mechanoreceptors in the aortic arch relay blood pressure (BP) levels through vagal nerve (VN) fibers to the brainstem and trigger the baroreflex, lowering the BP.

What does vagus nerve stimulation do?

Vagus nerve stimulation prevents seizures by sending regular, mild pulses of electrical energy to the brain via the vagus nerve. It is sometimes referred to as a “pacemaker for the brain.” A stimulator device is implanted under the skin in the chest. A wire from the device is wound around the vagus nerve in the neck.

What is the oculocardiac reflex?

The oculocardiac reflex also known as trigeminovagal reflex, Aschner phenomenon, Aschner reflex, or Aschner-Dagnini reflex, is a reduction in heart rate (bradycardia) associated with traction applied to extraocular muscles and/or compression of the eyeball 1) .

Does Oculocardiac reflex cause sinus bradycardia?

The oculocardiac reflex most commonly results in sinus bradycardia. However, it also has a reported association with reduced arterial pressure, arrhythmia, asystole, and even cardiac arrest.

How is Oculocardiac reflex used to evaluate syncope?

Historically, the oculocardiac reflex was used as a diagnostic tool to evaluate syncope, as well as to terminate supraventricular tachycardias, but this is no longer done given the limited clinical application and the associated risks.

What are the ophthalmologic applications of the reflex reflex?

The reflex has most often been encountered during ophthalmologic procedures such as strabismus surgery, though it has also been seen in cases of facial trauma, regional anesthetic nerve blocks, and mechanical stimulation.