Wilderness and Rescue Medicine 8th Edition

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Wilderness and Rescue Medicine

list throughout an evacuation effort. This is an example of the generic to specific principle at work: Treat what you can and evacuate for what you can’t. Increased Intracranial Pressure Increased Intracranial Pressure (ICP) is a swell- ing and pressure problem resulting in ischemia. The anticipated problem of increased ICP causes a lot of anxiety in wilderness and rescue medicine. This is part of the P in the STOPEATS mnemonic and the brain problem that is most likely to be fatal. We can worry about it and recognize it, but we cannot effectively treat it in the field. The one exception is increased ICP from high-altitude cerebral edema (HACE).

the brain will begin to fail resulting in the patient becoming combative or somnolent with severe headache and persistent vomiting. This pattern of worsening mental status, headache, and vomiting indicates increased ICP until proven otherwise.

Increasing ICP

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Signs and Symptoms:

EARLY

LATE

Mental status changes Severe headache Persistent vomiting

V/P/U on AVPU Seizures Posturing Dilated pupil Major vital sign changes

Bleeding and Edema

Swelling

Pressure Ischemia

“Regardless of the cause or rate of onset, the symptoms are the same.”

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A severe increase in ICP will drive the patient through V, P, and U on the AVPU scale with sei- zures , posturing , and pupil dilation as the brain stem infarcts as it is squeezed through the base of the cranium. At this point, survival without neurosurgical intervention is very unlikely. Field Treatment of Increased ICP Although there is no definitive field treatment for ICP, your careful attention to BLS—airway control, ventilation, body core temperature, and hydration—can certainly improve the outcome. Swelling develops and swelling resolves. Most patients can live through a period of increased ICP if you can preserve systemic oxygenation and perfusion. Emergency evacuation to surgical care is certainly the ideal plan, but support of vital body functions is equally essential.

Increased Intracranial Pressure

General Principles

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Mechanism: • Traumatic • Non-Traumatic Problem:

• Swelling • Pressure • Ischemia

Low Risk

High Risk

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Like other body tissues, the brain will swell when injured. Unlike other tissues, the brain is confined within the rigid compartment of the cranium. Swelling from bleeding or edema with- in this confined space can raise ICP to the point there is not enough difference between intracra- nial pressure and systemic perfusion pressure to allow blood to flow into brain tissue. In effect, the brain becomes ischemic and begins to fail. Like shock and respiratory failure, increased ICP has a typical pattern and spectrum of sever- ity regardless of its cause or rate of onset. Altered mental status is often the earliest vital sign indi- cator of increasing ICP with the patient becom- ing more disoriented or restless. These signs are usually accompanied by headache, photophobia (discomfort with bright light), and nausea. If the pressure continues to increase, the deeper layers of

Increasing ICP A’: Brain Failure

General Principles

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Field Treatment: • Urgent evacuation to neurosurgical care is ideal • Descent or Gamow bag for HACE • Protect airway, PROP • Maintain normal core temperature, hydration and calories

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