I work in a SICU that gets a lot of neuro patients. Yesterday I had a patient with a very bad SAH (I don't really understand what the Fischer and Hunt & Hess scales mean, but she had grades 4 and 5). She had arrested twice early in the admission, and was found to have an EF of 20%, so coiling had to be put off until she was stable. She finally was coiled more than 24 hours later, but came back from the coiling a 3T (she had been a 6-9T). Her pupils were fixed and dilated, and she had no cough, gag, or corneal reflexes. Doll's eyes and cold calorics tests were negative. So, the first apnea test was done. Her pCO2 rose by 30, but there was evidence of very weak respiratory effort, so she couldn't be declared brain dead. The apnea test was to be repeated in the morning (I left at 0730). I called the day shift nurse to find out how things had gone, and he told me the intensivist who was on in the morning said an apnea test couldn't be done because the patient was on too much norepi (she was on 24). However, she'd been on 30 when we did the apnea test the night before. They ended up going to nuclear med for a perfusion scan, which showed no blood flow to the brain.
My question is, has anyone heard this about the apnea test and norepi? She was also on vasopressin and dobutamine.