caloric test in brain death exam

Q: During 'caloric testing' for brain death examination, water should be used at? (select one)

A) Iced (zero) degree

B) Room temperature

Answer: A

During caloric testing for brain death examination, water should be chilled/iced. That's why it is also called the 'cold caloric test.' This is probably the strongest stimulus to determine brain death from all clinical exams. Few important points to remember besides using iced water:

• The external ear should be examined before confirming the patency of ear canal. Tympanic membrane should be visible.
• Each ear should be tested separately, 5 minutes apart. 
• At least 50 mL of ice water should be instilled into each ear canal 
• Head should be elevated to 30 degrees

If the eyes conjugately move toward the irrigated side, the brain death exam is negative (which means the patient can't be declared dead).

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References:

1. Hicks RG, Torda TA. The vestibulo-ocular (caloric) reflex in the diagnosis of cerebral death. Anaesth Intensive Care. 1979 May;7(2):169-73. doi: 10.1177/0310057X7900700210. PMID: 507352.

2. Machado C. Diagnosis of brain death. Neurol Int. 2010 Jun 21;2(1):e2. doi: 10.4081/ni.2010.e2. PMID: 21577338; PMCID: PMC3093212.

3. Munakomi S, Lui F. Caloric Reflex Test. [Updated 2023 Apr 5]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK557481/