Expert: Ronald Levy, M.D. - 4/2/2007

Question
Hello!  I'm hoping you can help me understand the half-life or cumulative affect of the morphine.  Trauma patient, non surgical mgmt of brain injury, was getting 2 mcg/h morph sulf through an IV for six days and all vitals were hanging in there.  On Day 7, an order was written to increase his dose to 10 mcg/h.  A few hours into this he definitely looked better.  I next saw him 24 hrs after the increase and I thought he'd been poisoned or something!
They did a brain death test on him at 30 hrs, IV line in place & he didn't breathe spontaneously so that was it for him.  Can you help me understand how much morphine was in his system at the end of this?

Answer
First of all, I think your doses are wrong as the normal parenteral dose for an adult is 0.8 to 10 mg/hr. The first question becomes "was it the morphine that lead to his deterioration or was it the brain injury itself". I tend to think it was the later as the doses you describe are not excessive by any means. We have some pain patients who receive over 50 mg/hr. As to how much was in his system, there is no way to determine that. As for the brain death test, one of the requirements for that test is that there are no drugs on board so they would have had to wait until the Morphine wore off (6-8 hours) before they could do the test. I don't know what the original brain injury was but it is nore likely that this is the culprit here. Of course this is just a guess on my part as I can't look at the record.

Hope this helps,

Ronald Levy, MD
Associate Professor of Anesthesiology
UTMB-Galveston