Otherwise known as “brain death,” death by neurological criteria was developed as a response to the development of advanced life support technology that was able to preserve vital functions despite devastating injury or illness. But, it is a confusing term and not just to families, but also to medical professionals who don’t deal with it on a regular basis. It is important to understand that “brain death” is no different than “cardiac death.” When discussing this with families, I like to explain, “if you were to have a massive heart attack and die, you don’t technically die because your heart stopped. You die because the brain dies. The brain dies because of lack of blood flow due to the fact that the heart has stopped.”

This may seem semantic, but it is an important note. Death is death, regardless of the proximate cause. Prior to the advent of advanced life support, people died of heart and lung failure before their brains failed. However, in the case of brain death, often brain injury is the proximate cause of death rather than secondary to the failure of other organ systems. There is often misunderstanding that “brain death” is not “real death” which can lead to the confusion among families that the medical team is “giving up.”

Recently, Dennis Kim shared an excellent article from the NEJM on Twitter regarding brain death determination that resulted in a good thread where providers who deal with this regularly share tips for having this conversation and performing this exam. Almost simultaneously, @pulmcritdoc shared this excellent summary on Instagram:

The various lobes of the brain all have slightly different functions and control different aspects of our lives. It’s good for the ICU provider to have a basic understanding of what is controlled where because it informs how any kind of brain injury will impact the patient. Whether it is acute ischemic stroke, intracerebral hemorrhage, or traumatic brain injury, damage to specific areas of the brain will result in somewhat predictable deficits. Maybe not predicting the degree of impact, but you can be aware of the possible types of problems your patient is likely to experience long-term.

This illustration from the Instagram account, @medical_guidelines, nicely summarizes what the various lobes of the brain control, and thus, what functions may be affected by an injury depending on location.

OK, so we’re not quite getting into the nuts and bolts of reading EEGs (although, I think we will attack that in a future post, at least a little). But, even the terminology on the EEG report can be confusing. with terms like “epileptiform discharges,” that sound like seizures but aren’t, and “generalized slowing,” how do you make sense out of all that?

Maybe you’re saying, “I don’t need an EEG. I don’t work in a neuro-ICU.” Or, “I can recognize seizures when I see them.” Well, firstly, if you work in a neuro-ICU, you probably have a lot more experience with EEGs and already understand how to read them (or at least the reports). Secondly, if working in neurocritical care has taught me one thing, it’s that almost ANYTHING can be a seizure. Seizures are often tonic-clonic and large muscle twitching, but just as often (probably more often), they look like anything but seizures. So, EEG is super helpful in any kind of encephalopathy or altered mental status that can’t be readily explained.

“When do I order a routine (spot) EEG and when do I want continuous/video EEG?” Well, that’s tricky and, like a lot in critical care, is somewhat institution dependent. Continuous EEG is probably better, it’s like just getting a 12-lead for a patient with arrhythmias but not putting them on some sort of continuous ECG. You may see some stuff, but you may miss some stuff. But, continuous is cost and labor intensive and lots of places have protocols for who needs the longer studies and when you can get away with a 1h.

This post from Casey Albin and Neha Dangayach over at EMCrit have written this great post on the basics of EEG and how to read the report. They go over when to order EEGs, when to do routine vs continuous, some of the basic terminology, and what they call the “not quite seizures.” So, check it out and hopefully it will help you make sense of the next EEG report you get.

One day soon, we’ll do a post on how to read (at least on a kindergarten level) the EEG yourself. Just so you can make sense of the squiggly lines before the epileptologist gets back with you. For now, I’ll leave you with what I was taught when I first started in neurocritical care. EEGs should be the opposite of ECGs. Rhythmic stuff is bad. You want the squiggly lines to be random-ish. Also, flat lines are bad (unless you’re trying to burst suppress someone). In that respect, I guess they’re exactly like ECGs.