Traumatic Brain Injury

Traumatic brain injury was the cause of over 837,000 visits, hospitalizations, and deaths in children in 2014. Management of these patients in the ICU can be challenging. Fortunately, we have Doctor Pramod Pulaamba, pediatric surgeon and intensivist at Montreal Children's Hospital, here to give us the cliff notes on TBI. Let's start off with a clinical case. A 15-year-old male presents to your ED after being hit in the head by a line drive ball during the 3rd inning of his baseball game. On the scene, he was confused but semi-coherent. On the ambulance ride over, his GCS declines to 8, eyes 2, verbal 2, motor 4. Blood pressure is 120/80 and heart rate 75. In the ER, he is intubated and a head CT demonstrates a small epidural. He has no other injuries at this time. So what's your initial management on this patient in the ER and what should we think about first? This is a, a, a pretty classic, uh, case, and considering that we've already have a CT scan and we've identified a small epidural, I think it's, it behooves us to immediately call our neurosurgical colleagues to ensure that this epidural bleed does not require surgical evacuation. Um, Sometimes if these epidurals are small, they may repeat the CT scan in several hours or they may just watch for signs of clinical deterioration before they go to the operating room. Um. Um-hum. This may be also a good time to discuss with your neurosurgeons about the roles of ICP monitoring, which would be very helpful for patients that are, that are being managed, uh, for potential, uh, intracranial pressure issues. So, how should we approach, um, hypertension in a patient like this? In, for patients with intracranial hypertension, generally, you would like to be able to have invasive blood pressure monitoring in order to have an accurate identification of blood pressure. You would also generally like to have some form of, uh, intracranial pressure monitoring so that you would be able to uh accurately calculate a cerebral perfusion pressure. So remembering that cerebral perfusion pressure is your mean arterial pressure minus your intracranial pressure. Most, uh, guidelines suggest that keeping a CPP greater than 45 would be the minimal acceptable. Sometimes in children, this would be, uh, 55. Um, and it, and so this should be your target. If you have ongoing issues of ICP that is above 20, that, uh, may also require, uh, ongoing treatment, uh, and or reevaluation with imaging. Um, when you're dealing with intracranial hypertension, um, sometimes, uh, it is, uh, it occurs, um, very suddenly, um, and the first thing that manifests is perhaps, um, Dilation of the ipsilateral pupil. Uh, it could be progressive, uh, bradycardia with hypertension. In those cases, you need to initiate very rapidly, uh, several things. First and foremost, um, and things that can be done very easily are to raise the head of the bed to improve, uh, venous drainage. You can provide the patient with oxygen. You can commence bag valve masking, uh, and if this patient is intubated, then the tidal monitor is extremely useful because you can then hyperventilate these patients down to a PCO2 of around 35, which would help vasoconstrict the brain and hopefully get some space. Um, if these patients have an ICP drain, then obviously one of the first things you would do would be to open the drain in order to, um, uh, again, evacuate any, uh, fluid and reduce pressure. Once you've opened the drain, um, I, what I like to do with respect to fluid resuscitation is to give 3% normal saline. My usual dose is 5 mL per kilogram. This will generally increase the serum sodium, uh, by 3 to 5 mL equivalents per liter. The reason why I like 2% normal saline, uh, actually, there's, there are several reasons. One, it's easy to give. Two, it keeps your sodium a little bit higher, so, therefore, um, you actually will have some some, some long-lasting ability to reduce cerebral swelling. Three, it has a much higher osmolarity limit, uh, compared to Mannitol. Uh, it's 360 instead of 320 millimoles. Um, uh, so because of that, uh, you can give more of it. Um, and also we know that hypotension in the context of, uh, closed head injury is a very poor, uh, prognosticator and therefore, we should at all costs, try to maintain blood pressure. So, in older children and teenagers, I'd like to keep, The systolic blood pressure above 90 or 95. If you have younger children, you could, you should use norms for age. I have used, um, inotropy, uh, such as norepinephrine in order to, uh, drive up the blood pressure in order to maintain cerebral perfusion. Um, and so these are all things that come into context. With respect to Mannitol, there is actually no evidence to suggest that one is better than the other based on the most recent guidelines, uh, that were published in pediatric critical care medicine. However, Um, one of the issues with, with, uh, Mannitol is it's diuretic effect, and that once you diurese, it may be very difficult to control and therefore, you may become hypotensive with that. Um, it's also important to remember that Mannitol does not work by diuresis effect first. It's actual first effect, which is within the first, 15 to 20 minutes of providing it is, it changes the rheology of the blood vessels. And by doing that, it allows the blood vessels to pass more freely through the cerebral circulation and therefore improve, um, oxygen delivery. So, that's actually something that some, some people don't know about, but the diuretic effect is actually the secondary effect and it happens afterwards. Definitely didn't know that. And the dose of Mannitol can be 0.5 g to 1 g, uh, per kilo, and, I guess another reason that I'd like to use 3% normal saline is that I've had people miscalculate and use 0.5 mg to 1 mg per kilo, which is completely an ineffective dose. And for these kids, is there any role for steroids? No, uh, at present, there is no role for steroids, uh, in these kids. Um, even for those with suspected spinal cord injury, it is, that is no longer considered, uh, um, um, Actually effective therapy and it actually may cause detriment. So, no, we do not routinely give steroids at all in these, into these patients. It's, um, what options are there for the neurosurgeon after, uh, conservative treatment of intracranial hypertension has failed? Um, so, I guess there are a few options to neurosurgeons. So, certainly, it could be simple evacuation. Um, and we do have patients where there isn't a true surgical lesion that can be decompressed, such as an epidural. Where you're dealing more with the diffuse axonal injury, but very difficult to control intracranial, uh, pressure. And in those cases, there, uh, uh, is emerging experience with the use of a decompressive craniectomy. Um, as a way to try to manage the, uh, these, the very difficult to manage, uh, ICP situations. Um, this is something that has to be discussed with your neurosurgeons. Uh, but certainly here at our center, um, if you're persistently measuring ICPs above 20 and having, uh, higher spikes, you know that that patient is going to slowly deteriorate to the point where they're not going to be salvageable. And in those contexts, uh, taking the patient to the OR to do a decompressive craniectomy, they actually keep the bone, they preserve it. Wait for things to settle down and then they can put the cranium back on again. So I, I, I think that should be in your back pocket as a, as an option. Uh, back to that just to clarify, so what is the preponderance of the data now suggesting on that because I know it's gone back and forth and it was a bit unclear. So, at the present time, uh, based on the most recent publication of the guidelines, this is the 3rd iteration of the Management of traumatic brain injury in Children that was published in Pediatric Critical Care Medicine. There's still no, uh, clear consensus that decompressive craniectomy does, uh, improve the outcome of these patients, but I'm, all I can say is that talking with many people across North America, uh, major Trauma centers that uh this is being used more and more. So I think it's just a matter of time before we accumulate enough data to definitively show that in certain severe situations that this may actually be helpful to improve the prognosis of these patients. And earlier I, I know you mentioned a neurosurgery consult and, and discussing when to rescan the head. When, if ever, would you consider using an MRI versus a CT? I think if you're in an acute situation where you have a very acute uh presentation of increased ICP, um, a CT scan is probably going to give you the, the best information because this is going to tell you whether you need to rush to the OR or not or perhaps put a drain in or do something like that. I, I use the MRI more for, after the 1st 48 hours, once the patient is a bit more stable, once I've been able to control ICP spikes, and I use that more as a prognosticator. Going to the MRI, the study takes longer. I generally don't use it as an acute indicator. So, CT scan for those acute episodes and then the MRI to provide you with more information. Uh, regarding the extent of the injury, this is actually very useful when it's very severe because it can help you. Counsel families and also direct what the, what the care plans are going to be for this child. And then you can repeat the MRI usually in a week's time, and that will give you a true extent of what the injury is and then you can have more meaningful discussions with respect to what the level of disability is going to be for that child. So MRI for guidance after you've basically stabilized them after like a couple of days or so. Yeah, our, our, our neurologists like MRIs. Everyone loves MRIs. You get a lot of detail, uh, but it's just not a good place to be when you have, uh, a critical patient when you can do a CT head CT, uh, in a matter of 5 minutes and then rush off to the OR as opposed to being in the MRI for, uh, 2030 minutes. Uh, so that's why I prefer the CT scan in acute situations. So just to continue our, our clinical case, our, our patient over the next few days is intermittently found posturing, hypertensive, tachycardic, tachypnic, hypothermic. Um, how do you first approach the management of sympathetic storming? Right, so sympathetic storming is thought to occur because there's an imbalance of the sympathetic and parasympathetic nervous systems as a result of the of the, of the head injury. Um, these patients exhibit, as this, this patient, uh, as our patient is exhibiting, uh, autonomic dysfunction and evidence of some loss of cortical control. So, uh, if you, if you don't treat the sympathetic storming, and it can actually lead to, uh, secondary brain injury or potentiate ongoing injury. Um, when patients hyperventilate, uh, this leads to vasoconstriction. I mean, this is one of the treatments that we use to treat ICP and that could lead to cerebral hypoxia and further, uh, cellular injury. If the patient is hypertensive or is developing arrhythmias. Again, the hypertension is not good because you could, uh, lead to, um, uh, hemorrhage, uh, within, uh, uh, within areas of the brain. Uh, and arrhythmias can lead to hemodynamic instability that, again, would, could lead to hyperperfusion in general, and therefore, again, uh, make your head injury worse. One of the other things also is that, uh, neurogenic pulmonary edema is sometimes common in these patients. Uh, and again, these patients are, are sometimes hypoxic, uh, difficult to ventilate, and in those situations, again, the hypoxia is not going to be good, uh, for the patient with the head injury. Um, When it comes to managing patients with sympathetic storming. Um, it's really based on the treatment, uh, of the symptoms. The cornerstone to treatment is sedation and pain control. This is usually accomplished with narcotics and or benzodiazepines as are your first line medications. Some people have used other medications such as bromocriptine, which acts on the hypothalamus, and it is there to help, uh, reduce, uh, hyperthermia, help reduce diaphoresis, uh, as well as, uh, reduce blood pressure. Um, oxycodone has also been used in certain patients because it has a bit of a longer acting effect, again, for pain control and for elements such as arrhythmias and or hypertension. Uh, people have used propranolol and or clonidine. Uh, propranolol, obviously, uh, can help control arrhythmias and, and, and lower blood pressure, and clonidine is an alpha 2 agonist, and it can actually help reduce, uh, levels of catecholamines throughout the body and hopefully, therefore reduce the ongoing sympathetic storm that the patient, uh, is experiencing. Clinical pearls Get a CT scan with initial presentation and for any acute change. And use an MRI when the patient is more stable. Frequent neuro exams are important. If the patient is intubated, it can actually be worse because you lose a clinical exam and become more reliant on other markers of elevated ICP. Be well versed in the management of ICP like maintaining blood pressure, raising the head of bed, oxygenating, sedating, and using 3% normal saline or Mannitol. Get to imaging and neurosurgery consult ASAP to determine the next steps of the surgical care pathway. This chapter is created and edited by Todd Ponsky, Alex Cassar, Alex Gibbons, and myself, Ray Hankey. Remember, knowledge should be free.