Sedation in Traumatic Brain Injury (TBI)

Traumatic brain injury (TBI) is not uncommon where I work.  Primarily they are due to motor vehicle crashes, however assaults come not to far behind this as a major cause.  We are fairly aggressive in our management of TBI and routinely RSI these patients.

This is a nice review of the various options in sedation for TBI.  There is of course no one perfect drug, they all have various benefits and downsides.  That said, given the choice I would have to say that ketamine is probably the safest, most effective and most versatile single agent out there.  Although not entirely without downsides, the alleged issues regarding ketamine and ICP in trauma have largely been debunked and it’s haemodynamic stability make it an excellent choice in the shocked patient.  It’s also excellent for pain relief, may be effective in status epilepticus, brilliant for the sick asthmatic who needs intubated and is possibly an excellent agent for the management of the agitated psychiatric patient.

Most of us however don’t have a great deal of leeway with the drugs we are allowed to administer.  This may not be entirely bad; there are some that argue that picking a drug and being familiar with it is the safest option.  Fentanyl and midazolam are the only choice for ground paramedics where I work.  Hopefully that will change in the future, although I am not holding my breath.

Given that most TBI occurs in the setting of multisystem trauma, the important thing to remember is that dose very much matters.  The shocked patient will require very little sedation as compared to the normal patient.  They will be far more susceptible to the negative hemodynamic effects as reduced volume means that any effect on the container will be magnified.  However they will also require more neuromuscular blockade than usual.

So, less sedation, more paralysis and may the Gods of the Laryngoscope smile upon you.

 

Flower, O., & Hellings, S. Sedation in Traumatic Brain Injury. Emergency Medicine International, 2012, 11.

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3 Responses to Sedation in Traumatic Brain Injury (TBI)

  1. Tingles says:

    “So, less sedation, more paralysis and may the Gods of the Laryngoscope smile upon you.”

    I’m not sure I entirely agree. We know that two things will adversely affect outcome from TBI – hypoxia and hypotension. We also know that control of ICP (or more importantly, maintenance of CBF) is important. While we cant measure ICP in the prehospital phase, we can attempt to limit its effect by controlling CO2, administration of hypertonic saline, and judicious use of sedatives and analgesia. The risk of using lots of NMBA and less sedation / analgesia is increased cerebral oxygen demand due to the patient being “too light” or in pain leading to increased sympathetic stimulation which raises ICP. NMBAs also masks seizure activity. Of course this needs to be balanced against the adverse CVS effects of some sedatives / analgesics. I am fortunate to have a number of options, but ketamine is commonly used in my service with good effect. If you have to use fent / midaz, have you tried using less midaz and more fentanyl?

    My thoughts – NMBAs should not be used in place of adequate analgesia and sedation.

  2. Tingles says:

    I just re-read my post and I would like to clarify – I am not against neuromuscular blockade. It does have a place in the management of TBI, but as an adjunct to an effective analgesia / sedation package and not as a replacement.

  3. ambofoam says:

    I agree, under no circumstances should a patient have long term paralysis without adequate sedation. My point was merely that in the shocked patient, adequate analgesia/sedation can be achieved with lower doses and the shocked patient is at greater risk from the unwanted haemodynamic effects of sedation. Even using the haemodynamically “stable” drugs like ketamine or fentanyl may precipitate drops in BP in the patient who is dependant on sympathetic tone to maintain perfusion.

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