Page 61 - JSOM Summer 2022

time. This dynamic nature of TBI means prehospital provid- cricothyroidotomy. Consider intubating TBI patients with GCS
ers must frequently reassess the patient and adjust their treat- ≤ 8 who are unable to maintain their airway or those who re-
ments. The objective of this section is to highlight some of the main hypoxic despite supplemental O . This GCS cutoff is not
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most critical TBI treatments in the hospital setting, and discuss a hard and fast rule and the decision to ‘take an airway’ must
them in light of the TBI pathophysiology (Table 4). 21,22 be based on clinical exam and patient status. Aim to achieve
Spo > 95% and end-tidal CO (EtCO ) 35–40mmHg. 25,26
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Hemodynamics Note that EtCO reading is normally 2–5 points lower than
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A systolic blood pressure (SBP) < 90mmHg or decrease in MAP the actual Paco due to the anatomical dead space (i.e., the
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below 60mmHg, even if momentary, can significantly increase airway and ventilator circuit), and this difference can increase
one’s mortality risk after TBI. 23–25 This is not surprising given in trauma patients with lung injury. Prophylactic hyperventi-
the brain’s dependence on CBF. Traumatic brain injury alone lation (Paco ≤ 25mmHg or EtCO ) is not recommended be-
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rarely causes hypotension unless the patient is already in the cause it artificially lowers Paco (recall that this triggers the
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last stages of brain herniation. Since the average adult human brain blood vessels to constrict), leading to the possibility of
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skull volume is 1.5L with little room to spare, intracranial brain ischemia, stroke, and worsened outcome. Furthermore,
hemorrhage will lead to signs and symptoms of high ICP long unless clinically indicated (see “Intracranial Pressure”), hyper-
before hemorrhagic shock is present. Importantly, bleeding is ventilation should be avoided in the first 24 hours after TBI,
an enemy of TBI patients. Every red blood cell (RBC) is needed during which CBF is compromised the most. 25
to carry oxygen to the injured brain. Therefore, expeditiously
control all hemorrhage sources, including scalp hemorrhages, Sedation and Paralysis
to keep the RBCs inside the patient. Do not neglect scalp blood Analgesics, sedatives, and paralytics help manage anxiety and
vessel injuries; they often continue to bleed without treatment, agitation and assist greatly with procedures and transport.
due to the vessels’ inability to constrict well. Use whole blood However, routine use of sedatives and paralytics in TBI pa-
(if the patient has lost blood volume) or normal saline for re- tients has been associated with higher incidence of pneumonia,
suscitation to maintain normal osmolality (to avoid harmful longer duration in intensive care, and sepsis. 25,28 They also im-
fluid shifts) and blood viscosity (to improve circulation and pair clinical examination. Therefore, early use of sedatives and
O delivery to the brain). Aim to achieve SBP > 110mmHg. 26,27 paralytics should be reserved for those who require invasive
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Again, CBF is determined more by CPP and MAP than by airway procedures, exhibit clinical evidence of high ICP, or
ICP. Therefore, treatment of hypotension should be a priority. have agitation and psychosis that are very difficult to manage.
Fluid ins and outs (I&Os) become important for assessing vol- Neuromuscular blockade (paralytics) should be reserved for
ume status and responses to ICP treatments. Therefore, place when sedation alone is inadequate.
an indwelling catheter or use a graduated cylinder to measure
urine output (UOP). Goal UOP is 30–50 mL/hour. Elevated Intracranial Pressure
Prehospital providers should always attempt to minimize ICP
Airway, Oxygenation, and Ventilation elevation in TBI patients. Optimizing CBF and improving ve-
The brain is sensitive to both O and CO levels. O keeps the nous drainage (so as to match blood flow in and out of the
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brain cells alive and CO controls how much O is delivered to head) will help maintain normal ICP and mitigate secondary
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them (because the brain’s blood vessels adjust their diameter injuries. General ICP reduction measures should be considered
based on the CO levels). Therefore, both need to be tightly in all TBI patients (see Table 3).
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controlled after TBI. Oxygen saturation (Spo ) < 90% or Pao
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< 60mmHg significantly worsens the risk of death after TBI When high ICP is suspected based on clinical exam (see “Di-
by nearly 3-fold when combined with SBP < 90mmHg. 23,24 agnostics”), prehospital providers should first ensure that all
Consider all options, including nasopharyngeal airway, bag- the general measures have been followed (Table 3). Many of
valve mask, endotracheal or nasotracheal intubation, and them can help rapidly lower the ICP. Hyperosmolar therapy
TABLE 4 Summary of Treatments for Traumatic Brain Injury (TBI) Patients
Category Treatment Recommendation Rationale
Airway • Intubate (if the patient cannot protect airway) Protect the airway, as the patient has lost the ability
to do so on their own.
Breathing • Aim to achieve EtCO 35–40mmHg Aggressive hyperventilation causes vasoconstriction
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• Prophylactic hyperventilation is not recommended. In the setting and can worsen ischemic brain injury.
of impending herniation (based on clinical presentation), briefly Optimizes O delivery to the injured brain that is
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hyperventilate to a Paco of 30–35mmHg prone to hypoxic and ischemic injuries.
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• Aim to achieve Spo > 95%, providing supplemental O as necessary
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Circulation • Aim to achieve SBP > 110mmHg Cerebral autoregulation may be dysfunctional. BP
• Gaining IV/IO access and resuscitate to meet the SBP goal must be maintained to meet the cerebral blood flow
demand.
Disability • Assess GCS score or AVPU Neurological status of a TBI patient can rapidly
• Repeat frequent neurological assessment evolve as the injuries progress. Establishing initial
• Monitor for signs and symptoms of intracranial hypertension examination followed by frequent repeat examination
• Actively treat pain, agitation, anxiety, nausea is the only way to understand the clinical course of a
• Always perform maximal spine precautions patient. Always assume there is a spinal injury.
Environment • Maintain core temperature 96–99.5°F (35.5–37.5°C) Fever or shivering can be harmful. TBI patients may
not be able to effectively regulate body temperature.
EtCO = end-tidal CO ; Spo = oxygen saturation; SBP = systolic blood pressure; IV/IO = intravenous/intraosseous; GCS = Glasgow Coma Scale;
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AVPU = Alert, responsive to Verbal stimulation, to Pain stimulation, Unresponsive.
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