There are a lot of times where a neurologist will not want to treat the BP until the SBP >180 or even >200, such as in cases of ischemic stroke...lowering the BP too much would deprive the brain of blood, O2 and nutrients.
I don't work on a neuro floor but all of our docs go by "Keep MAP >____" as opposed to the SBP.
Good question. It could be an institutional preference. We cover our hospital's Neuro/Neurosurgey ICU's as an intensivist consult service and I also notice that our Neurosurgeons and Neurovascular physicians also prefer to use SBP in driving the hypertension goals for patients on Triple H Therapy. There is no clear answer why. There are studies on cerebral hemorrhage that used SBP in determining what the BP goal is as far as blood pressure lowering but I haven't found an overwhelming preference to SBP with Triple H. In fact, I found a review article that actually surveyed practices among Neurocritical Care Society members and the respondents were split on either using MAP (52%) and using SBP (49%). Clearly, there doesn't seem to be a consensus on this yet.
Are you a neuro critical care team? Again, it just doesn't make sense when your cpp is calculated via map.
The reason I ask is that we have put people on phenylephrine, norepinephrine, vasopressin, and epinephrine to reach ridiculous map goals via sbp (and most time neurosurgeons won't believe our artlines) while these patients maps are in the 140s to maintain a sbp 180-200.
MAP is a more consistent measurement and is the better perfusion indicating metric. BP is dynamic, but overpressure injury in neuro is going to come from the peak overpressure, SBP. So I'd imagine that the parameters are built upon the measurement reflecting the problem being addressed, promoting cerebral perfusion vs protecting against anyeurism/hemmorage. Or so I understand it... someone tell me if I am way off.
Summit, that makes sense in the general scheme of things in terms of microvascular injury to brain tissue and hemorrhage risk. Many studies in stroke and aneurysmal bleeding recommend SBP measurements as the goal. There are even new studies that say that a high SBP in adults is a precursor to later cognitive issues in older age. However, I thought the OP was specifically asking about Triple H, a therapy which is used in secured anuerysms where the active issue is vasospam and no longer bleeding.
I was only asking about triple H therapy for vasospasm patients.
I think we would have better cardiac outcome with the same neuro outcome if we used maps. A lot of times these patients require 5 pressors and inotropes to get the patients sbp to 200. Meanwhile there ef goes from normal to 20% fast.
I'm a newer ICU nurse, but I asked the same question of one of our Intensivist docs. He stated that current research suggests that for any patient with risk of increased ICP should maintain a MAP above 70 or more depending on physician preference since it is shown that 65 is needed for sufficient profusion and the extra is needed to perfuse the brain tissue in order to counteract the added pressure from swelling/bleeding or whatever is raising the ICP. For other patients he stated that often it just falls to physician preference and for him he titrates vasoconstrictive meds based on a SBP when the patient's baseline pulse pressure is widened. This is because the relative low DBP's can greatly affect what MAP calculation and make it less accurate in relflecting perfusion.... This helped me, I hope it helps you too.