Increased Intracranial Pressure (ICP) Management

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Teaching Video:
youtu.be/e-83DanOgF8&list=PLOlpsJ0eDlASRw1LywI2iGfzDTqxlAYFJ

Increased Intracranial Pressure (ICP) Management

Increased intracranial pressure (ICP) is a serious complication of head injuries and can lead to poor outcomes if not managed appropriately.  The Monro-Kellie doctrine states that the skull is a rigid container, and any increase in volume within this container (brain, blood, or CSF) will result in a rise in ICP.

Therefore, management of increased ICP focuses on reducing intracranial volume.  Hyperventilation, although controversial, can be used in moderation (PaCO2 of 35-40 mmHg) to induce cerebral vasoconstriction and reduce intracranial blood volume acutely.  Mannitol, an osmotic diuretic, can be administered to reduce brain edema and lower ICP but should be avoided in hypotensive patients.  Neurosurgical consultation is crucial for any patient with signs of increased ICP, as surgical intervention may be necessary to evacuate mass lesions or control bleeding.  

Teaching Video/Podcast:
youtu.be/e-83DanOgF8&list=PLOlpsJ0eDlASRw1LywI2iGfzDTqxlAYFJ

The management of elevated ICP is crucial in treating various neurological conditions, such as traumatic brain injury, stroke, and certain types of tumors. Increased ICP can lead to severe complications, including cerebral ischemia, herniation, and permanent neurological damage. Therefore, prompt recognition and appropriate management strategies are essential.

Initial Management
1. Raise Head of the Bed: This simple maneuver helps facilitate venous drainage from the head, thereby reducing intracranial venous pressure and potentially lowering ICP. It is a non-invasive and easily implemented initial step in managing increased ICP.

2. Manage Pain and Vomiting: Pain and vomiting can exacerbate ICP by increasing intrathoracic pressure and decreasing venous return from the brain. Adequate analgesia and anti-emetic medications should be administered to alleviate these symptoms and prevent further ICP elevation.

Hyperosmolar Therapy
The administration of hyperosmolar agents is a cornerstone in managing increased ICP. These agents create an osmotic gradient that draws fluid from the brain parenchyma into the vascular system, thereby reducing cerebral edema and ICP.

1. Hypertonic Saline (3% NaCl): Administered at a dose of 3-5 mL/kg as a bolus, hypertonic saline is effective in lowering ICP by inducing fluid shifts out of the brain.
2. Mannitol: A potent osmotic diuretic, mannitol is given at a dose of 0.25-1 g/kg as a bolus to reduce ICP by dehydrating the brain. Smaller doses (0.25-0.5 g/kg) have been shown to be as effective as larger doses in reducing ICP acutely.
3. Sodium Bicarbonate: In cases of metabolic acidosis, 1-2 mEq/kg of sodium bicarbonate can be administered to maximize serum sodium levels up to 155 mEq/L, thereby enhancing the osmotic gradient and reducing ICP.

Other Interventions

1. Hyperventilation: Controlled hyperventilation to achieve a target PaCO2 of 30-35 mmHg for a maximum of 1-2 hours can be employed as a temporary measure to reduce ICP. This intervention decreases cerebral blood flow and intracranial blood volume by causing cerebral vasoconstriction.
2. Neurosurgical EVD Placement: In cases of refractory or rapidly increasing ICP, the placement of an external ventricular drain (EVD) may be required. This invasive procedure involves inserting a catheter into the ventricular system to continuously drain cerebrospinal fluid (CSF), thereby relieving elevated ICP.

ICP Monitoring
In ICP monitoring, ventricular-fluid pressures are recorded from a zero baseline; the normal range is 0 to 15 millimeter mercury. Pressures usually are expressed in millimeter mercury rather than millimeter H2O in order to facilitate comparison with mean systemic arterial pressures. 
The difference between mean ventricular pressure (ICP) and mean arterial pressure (MAP) indicates the pressure at which the brain is being perfused with blood (CPP).
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