Medical Management

SEDATION

There is a delicate balance when sedating patients with TBI. When transferring casualties to a neurosurgical capability for initial assessment, avoid long-lasting sedation or paralysis as this impedes the ability to evaluate the patient. However, medication selection should not override the need to safely transport the casualty.

- Propofol can be used for sedation, but caution must be used to avoid hypotension.25
- Ketamine is also useful for sedation (and can also provide some analgesia) as it avoids the significant hypotension associated with propofol and there is evidence it lowers intracranial pressure (ICP).34-40
- When narcotics are utilized for pain management, intermittent narcotic doses are preferred over continuous infusion.
- Routine paralysis of TBI patients should be avoided. If paralytics are needed, vecuronium is preferred because it is readily available in the austere environment and does not require refrigeration. Bolus dosing is preferred over continuous infusion. The recommended initial dose is 0.08 to 0.1 mg/kg given as an intravenous bolus injection. Paralytics should only be used if the patient is appropriately sedated. In general, paralytics should only be used for high-risk transport.

INTRACRANIAL HYPERTENSION

Despite controversy on the use of invasive monitoring to measure ICP, treatment of known or suspected intracranial hypertension remains a cornerstone of therapy in patients with severe brain injury.42

Intracranial hypertension should be suspected based on certain clinical criteria if no CT scan or intracranial monitor is available. These criteria include:

- GCS Motor Score < 4
- Pupillary asymmetry
- Interval development of pupillary asymmetry > 2mm
- Abnormal pupil reactivity
- Decrease of motor score by > 1
- New motor deficit
- Hypertension with Bradycardia
- If an automated pupillometer is present, an NPi < 3 on one or both eyes is concerning for raised intracranial pressure.

If treatment for intracranial hypertension is indicated prior to arrival to a neurosurgical capability, initiate hyperosmotic therapy with one of the following:

1. Hypertonic Saline42,43 (Appendix B)

- 250ml bolus of 3% saline administered over 10-15 minutes or a 30cc bolus of 23.4% saline.
- In a location with no neurosurgical capability for definitive treatment, infuse 3% saline at 50-100ml/hr for resuscitation with goal serum Na level of 150-160mmol/L. If in the rare circumstance, chronic hyponatremia is suspected, elevation of plasma sodium by 3-5mmol/L over 2-4 hours is recommended.
- Place central venous access to administer hypertonic saline and vasoactive medications, particularly if it is anticipated to be needed long term. Subclavian veins are preferred, followed by femoral, and lastly internal jugular.

2. Mannitol

Avoid Mannitol during the initial resuscitation period when ongoing bleeding has not been ruled out and in hypotensive casualties (or any casualty with the risk of bleeding).

Consider using Mannitol only if there is no availability of hypertonic saline and there is a significant concern for imminent herniation as evidenced by signs of intracranial hypertension described above.

- Mannitol 1g/kg bolus IV.25
- Hypotension after mannitol administration must be predicted and avoided. Urine output should be replaced with isotonic fluids.
- When treating patients with osmotic agents, monitor serum sodium at least every 6 hours.

ANTIEPILEPTIC MEDICATIONS AND SEIZURES

Seizures are common after severe brain trauma. Administer seizure prophylaxis to avoid the hemodynamic changes and increased cerebral metabolic activity caused by seizures. Seizure medications help prevent early post-traumatic seizures, but do not prevent all seizures. Up to 25% of patients with severe TBI will have seizures even with prophylactic treatment. Fifty percent of seizures may be non-convulsive in nature. Patients with subdural hematoma, neurosurgical procedure, or penetrating brain injury are at the highest risk of seizures. Post-traumatic seizures have been shown to increase morbidity and mortality after trauma.44-47

- If severe TBI is suspected, seizure prophylaxis should be administered during the initial evaluation and within 30 minutes of arrival.
  - Preferred agent: Levetiracetam (Keppra) 1500mg IV loading dose, followed by 1000mg IV BID
  - Second line agent: Lacosamide (Vimpat) 400mg IV loading dose, followed by 200mg IV q12hours.
  - Continue seizure prophylaxis for 7 days after a moderate or severe TBI.25,48-52 (Appendix A)
  - Seizure medications should be continued past post-injury day seven if the patient had evidence of seizure activity.
  - Rapid assessment and treatment of seizures is important to prevent secondary neurologic insult. Use a rapid response EEG device (if available) to diagnose seizures accurately and quickly.54-58
- Active Seizures

Lorazepam 1-2mg IV or Midazolam 5-10mg IV. Lorazepam is preferred. If no IV access, Midazolam IM is as effective as Lorazepam IV

OTHER PRECAUTIONS

- Maintain normothermia. Avoid and treat hyperthermia.
- Elevate head of bed to 30-45° or use reverse Trendelenburg position for suspected concomitant spine/spinal cord injuries.
- Gastric ulcer prevention with an IV PPI should be started within 12 hours of admission.
- Consider enteral nutrition according to Nutritional Support Using Enteral and Parenteral Methods.59