|
|
Cerebral resuscitation
|
|
|
||
|
|
Neither the brain nor the spinal cord can expand too much without pushing up against the bone that surrounds them. According to the Monro Kellie Hypothesis of intracranial pressure dynamics, intracranial pressure and volume are directly related: as the volume of brain and other tissue inside the skull goes up, since the skull cannot expand, pressure inside it goes up. Intracranial volume can be divided into three "compartments". If one compartment's volume goes up or down the total volume goes down unless one or both of the other compartments increase their volume to compensate.
Intracranial volume can be divided into three "compartments". If one compartment's volume goes up or down the total volume goes down unless one or both of the other compartments increase their volume to compensate.
Edema is excessive water in tissue. Brain edema results from entry into brain tissue of water leaking through an incompetent blood brain barrier
An local increase in brain volume in an area anatomically predisposed to herniation can cause movement of tissue from one to another intracranial compartment (herniation).
Increased intracranial pressure
According to the Monro Kellie Model, an increase in the volume of brain tissue resulting from an increase in its water content (i.e. cerebral edema) must result in an increase in intracranial pressure (ICP) unless the volume of one of the other compartments (vascular or CSF) decreases to compensate and maintain intracranial pressure unchanged.
Historical information that helps predict the typically delayed onset of neurologic deterioration and potential progression to coma, herniation, and death of brain swelling is seen with:
Trauma: subdural hematomas frequently have brain swelling out of proportion to the thickness of the clot.
Stroke: brain swelling will worsen over 72 hours.
Infection:
Tumor:
Management of brain swelling is according to the Monro Kellie Model.
Monro Kellie Model: Intracranial volume can be divided into three "compartments". If one compartment's volume goes up or down the total volume goes down unless one or both of the other compartments increase their volume to compensate.
Increased Intracranial Pressure (ICP) Monro Kellie Model
Decreases water in brain tissue (and decreases intracranial pressure as predicted by Monro Kellie model).
Constricts cerebral arteries by making the CSF that bathes them more alkalotic.
Complications of hyperventilation include systemic alkalosis with hypokalemia.
Mechanical ventilation risks formation of lung bullae/pneumothorax.
Out of favor. Avoid.
Never hyperventilate to pCO2 < 30 mmHg
Risk of hypovolemia, hypokalemia, hypotension. Monitor fluid status.
Mannitol 1 gm/kg with Lasix 40 mg IVP.
Osmotic diuresis (Mannitol):
Renal diuresis (Lasix):
top
|
|