After induction of anesthesia, surgeon holds medial rectus and anesthetist looks at the monitor to check?
ANSWER: (A) Oculocardiac reflexREF: Miller's Anaesthesiology 7th Ed Ch 75OCULOCARDIAC REFLEXThe oculocardiac reflex was first described by Aschner and Dagnini in 1908.Traction on the extraocular muscles or pressure on the globe causes bradycardia, atrioventricular block, ventricular ectopy, or asystole. It is especially seen with traction on the medial rectus muscle, but can occur with stimulation of any of the orbital contents, including the periosteum.The reflex is trigeminovagal. The afferent limb is from orbital contents to ciliary ganglion to ophthalmic division of the trigeminal nerve to the sensory nucleus of the trigeminal near the fourth ventricle. The efferent limb is via the vagus nerve to the heart.The reflex maybe seen more often with procedures under topical anesthesia. Retrobulbar block is not uniformly effective, however, at preventing the reflex. Orbital injections can trigger the response. The response is exacerbated by hypercapnia or hypoxemia.In the event of arrhythmia, the anesthesiologist first should ask the surgeon to stop manipulations. The ventilatory status is assessed. If significant bradycardia persists or recurs, intravenous atropine is administered in 7 ug/kg increments. Rarely, severe bradycardia or asystole occurs. Although chest compressions might be required to allow the atropine to circulate, usually the heart rhythm returns to normal isnth cessation of manipulation alone. The response fatigues with repeated stimulation.Pretreatment with intravenous atropineorglycopyrrolatecanbeeffective. Pretreatment may be indicated in patients with a history of conduction block, vasovagal responses, or b-blocker therapy
Oculocardiac reflex
Hypertension
O2 delivery
Response to Painful stimulus
Anaesthesia For Special Situations