Increased Intracranial Pressure and Spinal Cord Injury

Increased Intracranial Pressure (ICP)

• Purpose of Monitoring ICP: Elevated ICP is a critical concern because it can lead to secondary complications that worsen patient outcomes.

• Normal Range of ICP: Generally accepted range is between 10-15 mmHg.

• Interventions for High ICP: Start interventions when ICP exceeds 20 mmHg for 20 minutes or longer to avoid herniation, which is fatal.

Understanding ICP Spikes vs. Sustained Increases

• Spikes vs. Sustained ICP: A brief spike in ICP (e.g., to 35 mmHg when rolling a patient) is less concerning than a sustained increase.

Manifestations of Increased ICP

• Early Manifestations (in Green):

  • Declining Level of Consciousness (LoC)

  • Restlessness

  • Irritability

  • Confusion

  • Headache

  • Unilateral weakness

  • Pupil changes

• Late Manifestations (in Blue):

  • Severe headache

  • Deterioration of LOC to coma

  • Erratic respiratory rate (apnea or hyperventilation)

  • Tachycardia (rapid, thready pulse)

  • Hypotension

  • Hyperthermia

  • Projectile vomiting

  • Loss of corneal, cough, and gag reflexes

  • Posturing

  • Seizures

  • Fixed pupils (non-reactive)

  • Flaccidity

  • Cushing's Triad:

    • Hypertension with widened pulse pressure

    • Bradycardia

    • Bradypnea.

Monro-Kellie Hypothesis

• Cranial Volume: Fixed volume in the cranial cavity comprising brain, blood, and cerebrospinal fluid (CSF). An increase in any component requires a compensatory decrease in others to maintain balance.

• Consequences of Imbalance: Increased blood volume (e.g., bleeding) leads to reduced space for brain and CSF, resulting in increased ICP.

Assessment

• Neuro Assessment: Regular neuro assessment, ICP monitoring, can include arterial lines for hemodynamic monitoring.

• ICP Monitoring Methods: Common methods include a bolt or external ventricular drain (EDD).

• Normal ICP Values: Remember, aim for ICP readings ideally below 20 mmHg.

Diagnostics/Procedures

• CT/MRI

• Craniotomy

• Burr holes

• Cranioplasty for edema

• Cerebral Ventricular drains

Cerebral Edema and ICP

• Effects of Cerebral Edema: Increases capillary pressure and leakage contributing to elevated ICP. Increased pressure compresses blood vessels leading to ischemia, which prompts autoregulation (vasodilation) and further elevates ICP.

• Role of CO2: High CO2 causes vasodilation (increased ICP) while low CO2 leads to vasoconstriction (decreased blood flow). Important to control CO2**

Interventions (Keep ICP down to avoid herniation)

• Cerebral perfusion pressure (CPP) Needs to be less than 70

  • MAP- ICP= CPP

• Elevate head of the bed to 30 degrees for improved venous outflow.

• Maintain midline positioning to prevent venous outflow obstruction.

• Monitor and control patient temperature, as extremes can increase ICP.

• Create a low-stimulation environment to reduce ICP.

• Limit suctioning to 10 seconds to mitigate ICP spikes.

• Mechanical ventilation to maintain CO2 (35-45) and paO2 (80-100)

• Use Mannitol to draw fluid out of the brain for immediate ICP reduction and monitor urine output as it can also lead to hypotension.

Medications

• Mannitol (Osmitrol): osmotic diuretic (Bolus ONLY!)

  Reduces ICP through drawing water out of neurons and decreasing intracranial volume when bolused. Also increases cerebral blood flow/oxygen delivery

  • Continuous ICP monitoring, run through filter,

  • Monitor- UOP, hypovolemia, hypotension, tachycardia, watch electrolytes

  May see MD order Furosemide (Lasix) as an adjunctive therapy to Mannitol

• Succinylcholine (Anectine): fast acting paralytic. Mostly seen IVP

  Intubation, decreases tissue oxygen demand, decreasing ICP. 

  • Monitor-Apnea, hyperkalemia

• Vecuronium (Norcuron): fast acting paralytic. IVP or as a drip 

  Intubation, decreases tissue oxygen demand, decreasing ICP 

  • Monitor-Apnea, hyperkalemia

Spinal Cord Injury Overview

• Classification of Spinal Cord Injuries:

  • Complete: No function below injury level.

  • Incomplete: Some function below injury level.

• Causes of Injuries:

  • Examples include hyperflexion, hyperextension, axial loading, and penetrating injuries.

  • Secondary Injuries- worsen the primary injury (Hemorrhage, ischemia, shock, edema

Assessment and Interventions for Spinal Cord Injury

• Primary Assessments: Always assess the respiratory system, particularly in cervical injuries due to impacts on the phrenic nerve leading to respiratory failure.

• Monitoring: Motor function, sensory function, bowel and bladder control, and vital signs. Perform ongoing neurological assessments including GCS.

• Respiratory Management: Monitor respiratory function closely; intubation may be required. Prevent atelectasis through incentives and ventilation support.

• DVT prophylaxis (TED hose, SED, Heparin, IVC filter)

• incentive spirometry

• Halo fixator to stabilize C-spine

  • If screw comes loose stabilize neck and call for help

• MAP greater than 90 (it takes more to perfuse spinal cord

Medications

• Methylprednisolone (Solu-Medrol): corticosteroid. Helps lessen secondary complications of SCI by reducing spinal edema. Scheduled blood sugar checks, avoid grapefruit (could increase med level), hyperglycemia

Complications of Spinal Cord Injuries

• Neurogenic Shock: ANS imbalance (increased parasympathetic), common in those with injuries above T6 within first 24 hours

  Can last weeks

  Hypotension, bradycardia, peripheral vasodilation, decreased LOC/UOP (may have paralysis R/T injury)

  Maintain airway, immobilize spine, fluids, vasopressors, control body temp

  Can lead to organ failure/death—more serious

• Autonomic Dysreflexia—ANS imbalance (increased sympathetic) caused by an irritant below the level of injury (injury above T6) (often constipation/bladder distention, constricted abdomen or extremity) p. 2078

• Signs/Symptoms

  • Sudden, severe throbbing HA

  • Severe hypertension

  • Bradycardia

  • Nasal stuffiness, blurred vision, N/V

  • Flushing/sweating above injury

  • Pale, cool, goose bumps, no sweating below injury

  • Feeling of apprehension/sense of impending doom

• Interventions

  • Sit in upright position

  • Call MD

  • Loosen tight clothing

  • Assess for and treat cause

  • Check catheter for kinks/obstructions—insert Cath if not in

  • Check for fecal impaction—disimpact

  • Make sure room temp isn’t too hot/cold

  • Give nitrates or nifedipine or hydralazine

• Spinal Shock—complete loss of motor, sensory, and reflex function below the level of the injury (peripheral neurons become temporarily unresponsive to brain stimuli, connection between brain and body is messed up) Can happen in any location

  Usually recover within 48 hours, can last weeks

  • Hypotension, bradycardia, flaccid paralysis

  • Maintain airway, immobilize spine, fluids, control body temp

  Supportive care will usually bring patients to recover on their own