I was discussing with my teacher about a pt. scenario. The patient was involved in a road accident. To keep it short, there were major head injuries, including internal head injuries, and hence high intracranial pressure (which would require a craniotomy). However, the patient also suffered severe abdominal bleeding from the spleen, as well as a possible pneumothorax. In regards to the severe abdominal bleeding, the pt. has becom hypovolaemic, and hence tachy, hypotensive, and hypoxic.
When I was discussing the need for hydration (along with blood transfusion), my teacher said that hydration is not a concern - due to the complication of the intracranial pressure. She said to consider the rold of dehydration in head injury, particularly regarding the balance between decreased volume, and the desire for increase in perfusion.
Is there a paradox here? Whats more of a concern - intracranial pressure, or hypovolaemia - which is leading to brain hypoxia?
Jun 4, '09
The Intracranial pressure has priority because it affects the functioning of brain cells. Priority is decided pretty much by what is going to die first. Brain cells die the most rapidly of any cells of the body when intracranial pressure is increased. Normal cells functions can not be carried out and that includes getting oxygen to the cells. Hypovolemia (water deprivation) takes a lot longer to kill a cell of the brain.
Jun 5, '09
If your patient bleeds out the ICP isn't going to matter. ABCs, address the bleeding first. Any green EMT could tell you that.
Source - Experience in prehospital EMS and neuroscience critical care
Jun 5, '09
Yes, MurseMikeD is correct. Any green ED nurse would also know that ABC (Airway, Breathing, Circulation) is the priority order. In fact, this is also taught in a basic BLS class, in addition to ACLS and TNCC (trauma nurse certification).
Think of it this way-if you don't have anything to circulate to the brain (meaning, blood loss) the brain won't get O2, so the effect of increased ICP won't matter because the patient dies from the hypovolemia (hypovolemia can also be caused from blood loss and is not restricted only to water loss-hypovolemic shock).
Jun 5, '09
As part of treating the "C" in ABCs, Giving blood/fluids will increase blood pressure, and therefore perfusion to the brain. Without brain perfusion, tissue dies. It's not uncommon for traumatic brain injury patients to have high blood pressure goals--this will make sure blood gets to the injured tissue and prevents further secondary injury. So, treat the blood pressure ASAP.
Better yet, give the blood to treat hypovolemia and find out if you can open up the EVD to decrease ICP. With an EVD, there's no reason why you can't treat the hypovolemia and ICP at the same time.
Look up CPP (central perfusion pressure) and how it's calculated. CPP is arguably the most importand factor in treating brain injury. It requires a high BP and a low ICP. If you understand CPP and how it can fluctuate and be treated, everything will fall into place.
Last edit by leosrain on Jun 5, '09
Jun 5, '09
You'll surely have an opportunity to learn the finer points of how cerebral perfusion pressure and mean arterial pressure relate to intracranial pressure at some point in your education. This is really a back-to-basics scenario though. Airway, breathing, and circulation are your top priorities, in that order. You treat those issues first, because they'll kill your patient first.
Air goes in and out, blood goes round and round, and any variation on that is bad.
Jun 6, '09
I agree, the issue here is does the pt have enough volume to maintain CPP? If the BP isn't sufficient to produce a MAP of at least 60, then perfusion to the brain is compromised. (CPP=MAP-CVP). It's all about having enough blood to perfuse, IMO. ICP can be reduced with a ventricular drain if it is out of control. Hope that helps.
Jun 7, '09
Agree with most - priority is always circulation. You can then get a drain in to get the ICP down.
Jun 16, '09
I've seen people A/O with ICP (brain bleed after a fall, hx. of coumadin use) who ultimately died from a herniated brainstem, but it wasn't immediate. Bleeding to death is. And since the pt in your scenario had a period of hypoxia, you want to oxygenate that brain ASAP. Bad can always be worse.
And while most of my hands on is with fresh CVAs, we want their BP up to aid in perfusion, too -- we can always give them mannitol if the ICP gets higher than the doc wants (but watch the kidney function).
Jun 16, '09
hypovolaemic will be the first issue...
I'm glad to see even though I haven't gone to clinicals yet I know the difference with this question.
Being a CNA is definitely worth it.
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