Ever wonder what doctors think about when they are prioritizing brain’s survival?
In this communication, I present the medical priorities physicians keep in mind when they are trying to optimize brain survival. And I present them in a pneumonic that will never let you forget it.
Emergency physicians, neurosurgeons, and general surgeons, especially trauma surgeons in particular, are always keenly aware of these key constraints when they focus on keeping the brain alive.
This discussion is for learning purposes only. Getting in a physician’s head. So, please… Let doctors be the ones deciding that kind of care.
And here’s the pneumonic!
“Bros before HOs“ — Brain before an “HO” word. You’ll see what I mean.
5 HO’s that decrease cerebral brain flow and so lead to secondary brain injury.
- HOt (normothermia is the goal)
- High CO2 🙂 (^^vent = goal)
HOt. Not good for the brain. Cooling the patient however in trauma situations has never really improved any outcomes. There is one paper however that proved that cooling the patient that required surgery to alleviate his brain disorder (like a bleed or something) was effective. But if surgery isn’t required, and cooling the patient at four to nothing. The goal is simply normal temperature. Hyperthermia is Bad for the brain.
HypOglycemia. Every one knows that the brain thrives on oxygen and sugar. So you got to keep the sugar levels “in the normal range” as best you can.
HypOtension. In a trauma situation, the last thing you want to do is lower systemic mean arterial blood pressure. You’ve got to keep that driving force pumping blood into the brain. Every ER doc knows this.
HypOxia. As stated above, the brain thrives on only two things really, oxygen and sugar. The brain, as complicated to tissue as it is, only requires these two things at all times.
And hypercarbia. This is the weakest contribution to the pneumonic. There’s really no “O” in hypercapnea (high CO2). So I like to think of it as High-CO2. And it’s easy to remember. You have to blow down CO2 somewhat to produce an alkalotic pH (greater than 7.4) in order to get the brain to constrict its blood vessels in order to retain a little acid to drive it back to 7.4, where it likes to be. And if you can get the cerebral blood vessels to constrict a little bit, that’s going to decrease flow. That in turn is going to decrease pressure in the brain. And that’s going to make the brain happy.
Brain before any of the H-oh words. That will prioritize the brain, and reduce the risk of secondary brain injury.