Answer:
Atropine test is a simple pharmacological test based on the absence of cranial parasympathetic nervous influence on the heart in brain dead patients and may be a useful adjunct to testing brain stem function. A tachycardic response would demonstrate an intact cranial parasympathetic outflow. 2-3 mg of Atropine IV is then given. If there is less than 10 % or no increase in heart rate, this supports the diagnosis of brain death. Additional confirmatory tests are however required.