Case of the Month #32 Brain Stem Death

Published 03/10/2022

What are the reflex arcs involved in each brain-stem test?

Test

Procedure

Afferent

Efferent

Pupillary Reflex

Bright light shone into each eye to look for direct and consensual pupil constriction

II

III

Corneal Reflex

Cornea is brushed looking for a blinking response

V

VII

Response to painful stimuli

Supraorbital stimulus looking for facial grimacing

V

VII

Vestibulo-ocular reflex

Tympanic membrane visualised. 50ml of cold water is steadily injected into each ear canal looking for eye nystagmus

VIII

III, IV, VI

Gag Reflex

Direct stimulation of the pharynx looking for gagging

IX

X

Cough Reflex

A suction catheter is passed down the endotracheal tube to stimulate the carina looking for a cough

X

X