Brain Death, Decorticate Posturing, Persistent Vegetative State and Locked-In Syndrome

by Carlo Raj, MD

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    00:01 Brain death, irreversible cessation of brain and brainstem functioning, regardless of cause.

    00:08 Requirements varies from, well, state to state, hospital to hospital.

    00:13 Comatose, absence of brainstem reflexes that we talked about.

    00:17 No spontaneous respiration.

    00:21 Absence of complicating factors: Hypothermia, sedatives, metabolic abnormalities.

    00:30 Approach to brain death.

    00:32 Here, we have an algorithm or flow chart.

    00:35 And from the flow chart, on the top, we go from the coma.

    00:38 Is it present? And if it is, your next step of management is going to be neuroimaging and maybe CSF evaluation, as long as intracranial pressure is not elevated.

    00:50 If you find something to be interesting, yes, then you want to start thinking about how to rule things out.

    00:56 Was it hypothermia? Was it intoxication? Was it sedatives? Or was it neuromuscular blocking type of agents? Was it metabolic in terms of severe electrolyte disturbances? Was it acid-based disturbance? Or was it endocrine type of crises such as Addison’s disease? So here, what we mean by this is the brainstem reflex such as a pupillary or the cold caloric or the doll’s eye, whatnot.

    01:19 Then you should perform an apnea test. This has the following steps: First ensure your patient is hemodynamically stable. Then adjust your ventilator settings to normocarbia, so that the partial pressure of C O 2 should be 35 to 45 millimeters of mercury. With this setting discontinue ventilator for 8 minutes. In brainstem death there are no spontaneous respirations.

    01:44 That’s what we call apnea - despite the hypercapnia. Also obtain an arterial blood gas at 8 minutes and then reconnect the ventilator. The partial pressure of carbon dioxide is expected to be 60 millimeters of mercury or more, or 20 m m H g above the baseline value.

    02:02 Next, what would you do? Clinical diagnosis of brain death is what you’re thinking.

    02:09 At this point, maybe, maybe, there is eligible for organ type of harvesting, because now at this point, you’re thinking about asking the family members or a power-of-attorney as to whether or not the harvesting of organ from your patient is your next step of management.

    02:27 As objective and as cold-hearted as it may seem right now, please make sure that you’re very objective on your boards and your wards.

    02:37 So, your patient here, even though you wish to be optimistic at some point, you must know what your next approach would be.

    02:46 Now, if the patient, no for harvesting, at this point, you get into disconnection or the ventilator becomes the question or the point of concern.

    02:59 Disconnect your ventilator.

    03:02 If yes, then you proceed with the donor procurement.

    03:05 Here’s a brief little overview of what you can expect from going from coma to brain death to your ventilator.

    03:13 Here, we’ll talk about the different types of posturing.

    03:17 And by this, I mean either decorticate or decerebrate.

    03:21 We talked about that Glasgow coma scaling.

    03:25 And now at this point, you were thinking about level of consciousness and whether or not your patient was even awake.

    03:30 As you move from six to one, at that point, I had pointed out to you different types of posturing that may occur as you lose more and more of your awakening.

    03:42 Here, we have decorticate.

    03:45 Would you please take a look at your patient? This is important.

    03:48 What I want you to do immediately is I want you to focus upon the elbows, and I want you to focus upon the ankles.

    03:56 You’ll notice here, please, that the elbows are flexed and the wrists are flexed in very tight posture, almost as if like you’re jumping out of a plane into the sea where you are just being aerodynamically efficient.

    04:13 And take a look at the toes, we have plantar flexion,, and all of this is then representing the posture that you can expect with decorticate.

    04:20 I need you to spend a little bit of time to make sure that you have firmly implanted the image of decorticate and its posture in your head.

    04:30 So, bilateral flexion at the elbows and wrists.

    04:34 Extension of the lower extremities.

    04:36 We have poor localizing value.

    04:39 Indicates a lesion.

    04:40 Where? One of the most important points on this slide is this.

    04:45 With decorticate, indicates a lesion above the red nucleus, above the red nucleus, above the red nucleus.

    04:56 Less ominous that of, what we’ll get into next, known as your decerebrate posturing.

    05:03 So, if this is above the red nucleus with decorticate, then decerebrate must be below the red nucleus where we have possible injury.

    05:14 Please take a look at decerebrate posturing.

    05:18 With decerebrate posturing versus decorticate, here immediately, I want you to jump to the elbows and the wrists.

    05:27 At this time, we find that the elbows are extended.

    05:31 And we also have the wrists that are extended.

    05:34 Completely opposite that of decorticate.

    05:38 The extension of lower extremity would be similar in both.

    05:41 And most typically, indicates a lesion.

    05:43 Where? Below the red nucleus and maybe, perhaps, the mid brain.

    05:47 Once again, below the red nucleus with decerebrate.

    05:52 Rarely seen in severe cases of toxic or metabolic encephalopathy.

    05:58 Be familiar with the posturing.

    06:00 One is called decorticate, the other one is called decerebrate.

    06:04 So, what does a vegetative state mean to you? A vegetative state may develop after prolonged coma with continued life support.

    06:13 Patients maintain respiration and autonomic functioning.

    06:17 Eye opens and may blink to threat and exhibits sleep-wake cycles.

    06:23 No awareness or interaction with the environment though with the vegetative state.

    06:27 Prolonged coma.

    06:30 Something called locked-in syndrome.

    06:32 Where is this occurring? You should be thinking pons immediately, most often due to hemorrhage.

    06:38 Patients unable to move extremity.

    06:40 Literally, they are locked in, unable to move extremity or face, unable to vocalize, they’re trapped in their own body.

    06:48 Extremely frustrating if you can imagine.

    06:50 Completely awake and often cognitively intact with careful testing.

    06:56 Can communicate with vertical eye movement and blinks, and that’s important.

    07:01 So, then you get into habit of communicating with your patient virtually with the eyes.

    About the Lecture

    The lecture Brain Death, Decorticate Posturing, Persistent Vegetative State and Locked-In Syndrome by Carlo Raj, MD is from the course Altered Mental Status and Coma. It contains the following chapters:

    • Brain Death
    • Decorticate Posturing
    • Persistent Vegetative State & Locked-In Syndrome

    Included Quiz Questions

    1. > 60 mm Hg
    2. > 50 mm Hg
    3. > 16 mm Hg
    4. > 66 mm Hg
    5. > 40 mm Hg
    1. Above the red nucleus
    2. Below the red nucleus
    3. Midbrain
    4. Pons
    5. Medulla
    1. Locked-in syndrome
    2. Persistent vegetative state
    3. Coma
    4. Decerebrate rigidity
    5. Decorticate rigidity

    Author of lecture Brain Death, Decorticate Posturing, Persistent Vegetative State and Locked-In Syndrome

     Carlo Raj, MD

    Carlo Raj, MD

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