Stimulation of trigeminal nerve during gap arthroplasty surgery causes?

 # Stimulation of trigeminal nerve during gap arthroplasty surgery causes?

A. Paroxysmal atrial tachycardia

B. Ventricular tachycardia

C. Bradycardia

D. Torsades de pointes

The correct answer is C. Bradycardia.

Trigeminocardiac Reflex (TCR) 

■ This basically means that stimulation of the trigeminal nerve causes vagally mediated bradycardia, which, in severe cases may even cause asystole. 

■ The trigeminocardiac reflex is the sudden-onset of dysrhythmia and hypotension during manipulation of any of the branches of the trigeminal nerve. The trigeminal nerve and cardioinhibitory vagus nerve constitute the afferent and efferent pathway in the reflex arc. 

■ In pediatric patients, the sympathetic nervous system is not fully developed, giving the parasympathetic nervous system greater control and increased tone. A severe and sudden bradycardia can often be the result of this parasympathetic hypertonia or "increased vagal tone " 

■ It is important to note that the incidence is inversely proportional to age with a sharp decline in incidence for children over the age of 3. 

■ Oculocardiac reflex (Aschner phenomenon) is a type of TCR due to stimulation of the ocular division of the trigeminal nerve.