Apnea test and norepi
- 0Oct 29, '05 by HillaryCHi everyone,
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.
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- 1Oct 30, '05 by papawjohnHey HillaryC
Sounds like your Pt had an extremely advanced case of DND (damned near dead). You must have done a really great job of resuscitating her and caring for her for some time--'cause usually a Pt doesn't get to that status (Levophed, Vasopressin, Dobutamine--IceWaterCalorimetrics, Apnea Test) in a short time. Good on ya!!
I don't have good insight into why one MD performed the Apnea test with Levo gtt at 30mcg/m and then the other did NOT with the same gtt at 24mcg. They have different ways of approaching their job--just like nurses do. My Bro-in-Law is a neurologist and I'll email him to see what he might contribute and post anything interesting.
You understand of course that the issue with the Levo is the vasoconstriction that would be restricting the circulation in the parenchyma of the Central Nervous System. The goal would be to have NO meds restricting that circulation before you decide that the Pt is brain dead. That's what the MD wants (but people in hell want ice water, as the old GI said).
For your info: Hunt-Hess Scale
I -minimal headache or nuchal rigidity
II -moderate headache or nuchal rigidity AND cranial nerve palsy
III -drowsiness, confusion, fixed deficit
IV -stupor, hemi-paresis, extention rigidity
V -deep coma, moribund
And: Fisher Scale
I -no subarachnoid blood visible
II -diffuse layer of blood
III -localized subarachnoid clot
IV -Intraventricular or parenchymal clot AND any subarachnoid clot
So if your pt had a Hunt-Hess 5 and a Fisher 4--she was really CTD (circling the drain).
I have a question about your post. You say her low EjectionFraction (20%) kept her from being 'coiled'. What is "coiling"? Is it a name for 'spiral Cat Scan'?
- 0Oct 30, '05 by sirI AdminQuote from papawjohnHello, John,
You say her low EjectionFraction (20%) kept her from being 'coiled'. What is "coiling"? Is it a name for 'spiral Cat Scan'?
Here is some good information on coiling after a subarachnoid hemorrhage (SAH). I am sure the surgery was delayed secondary to poor cardiac output.
- 0Oct 31, '05 by 1TulipHi y'all,
I asked the neurologist your questions. Here is his answer.
When you do an apnea test, there are two outcomes that would tell you the patient is brain dead. One, of course, is poor respiratory drive, hypercapnea, etc. The other is CV instability, i.e., the patient brady's down and/or drops their BP.
So, the first doctor was not wrong to do an apnea test on the patient who had pressors running. But the outcome was equivocal. The second doctor, wanting to get a clear cut answer, needed to be able to evaluate both criteria. If, perchance, during the second apnea test, the patient could mount some weak respiratory effort, but was not able to regulate heart rate and blood pressure, they would have failed the apnea test and the patient could be pronounced brain dead.
Does that make sense? Hope I explained it right.
- 0Oct 31, '05 by HillaryCThank you all for your responses. This has been very helpful. To answer some questions -- Gwenith, yes, I was referring to a Glasgow Coma Scale score of 3 (the T meaning she was intubated).
PapawJohn, I can understand why you would think this was a trauma patient. She was fine in the morning, then found on the floor by family with a massive aneurysm rupture out of nowhere. She was just in her late 40s. It was very sad; cases like that are so disturbing.
It's great to finally understand the Fisher and Hunt-Hess scales; it seems like we've been getting a lot of SAHs recently on my unit.
The neurologist's explanation about the apnea test does make sense, though it seems a bit weird that brain death could be declared in the presence of respiratory effort, however weak. I guess I have a lot to learn about the nervous system
Thanks again, everyone
- 0Nov 1, '05 by 1TulipYeah Hillary, I know what you mean about weak respiratory effort but still the pt. is "dead"??? But remember that cardiovascular control AND respiratory control centers are in the brain stem. Thus if either is not working well enough to support survival functions, then the patient is not only without cortical function, they've lost the most primitive parts of the CNS. It's an irreversible situation.
- 0Nov 29, '05 by Keysnurse2008PaPawJohn,
There are 2 types of aneurysms.One is a berry aneurysm and theses have small "necks " and are generally secured by opening the crani and surgically clipping it.The other type is a fusiform aneurysm...it has a looonnnnggg (long) irregular neck and is too large for a small surgical clip ...so they take these type patients to a Intervenetional radiology suite. And under fluroscopy/arteriogam...they take tiny coils...and insert them in the large neck of that fusiform aneurysm.It takes numerous coils to fill that large neck and occlude it off /secure it/seal it.I always tell everyone a good anaology is ...they are like little tiny tiny peices of a brillo pad.Imagine that and you will understand coiling. The coils are floated into place and then rbc's catch on them and seal them off.
- 0May 29, '06 by BRICKRNThis is one of those tough patients where it is very difficult to accomplish a complete all the requirements for the clinical exam to declare brain death. The considerations for halting an apnea exam, after a patient has met the examination of absent brain stem reflexes, include development of hypoxia ,hypotension or dysrythmia. As you were already on vasopressors the patient usually has difficulty tolerating acidosis(the reason you develop hypotension during the apnea test). We will almost always proceed to a confirmatory test like a nuclear med scan. The American Academy of Neurology Guidelines are available on line and help to answer questions regarding "accepted medical practice" and the declaration of brain death. If you work in a Neuro ICU and see cases like this often I would recommend getting Wijdiks book on determining brain death in adults. I have been involved in writing policies for the hospital where I work and found both references as excellent resources.