ICP and Monitoring

What is the most sensitive and reliable indicator of a patient neurological status?

Level of consciousness[cite: 206

Which anatomical structure controls arousal and the appearance of wakefulness?

Reticular Activating System (RAS)[cite: 206]

Which anatomical structure controls content and thinking processes?

Cerebral hemispheres[cite: 206]

What are the three categories assessed in the Glasgow Coma Scale (GCS)?

Eye Opening - Verbal Response - Motor Response[cite: 207]

What is the range of possible scores on the Glasgow Coma Scale?

3 to 15[cite: 207]

What GCS score indicates a severe head injury and requires intubation?

A score of 8 or less[cite: 207]

How is a verbal score documented on the GCS when a patient is intubated?

The letter T is appended after the total score[cite: 207]

What GCS score range indicates a moderate head injury?

9 to 13[cite: 207]

What are the three volume components enclosed within the rigid skull and their normal percentages?

Brain tissue 80 percent - Intravascular blood 10 percent - Cerebrospinal fluid (CSF) 10 percent[cite: 208]

What principle states that an increase in volume of one cranial component must be offset by a reciprocal decrease in another?

Modified Monro-Kellie Doctrine[cite: 208]

What is the first reciprocal compensatory response by the body to increased intracranial pressure?

Shifting or absorption of cerebrospinal fluid (CSF)[cite: 208]

What is normal intracranial pressure (ICP)?

0 to 15 mmHg[cite: 209

What is normal cerebral perfusion pressure (CPP)?

70 to 100 mmHg[cite: 209]

What is the mathematical formula for calculating Cerebral Perfusion Pressure (CPP)?

CPP equals MAP minus ICP[cite: 209]

What is the formula for Mean Arterial Pressure (MAP)?

MAP equals Systolic BP plus two times Diastolic BP divided by 3[cite: 210]

What target vitals and pressures define clinical goals for neuro injury management?

CPP greater than 70 mmHg - MAP greater than 90 mmHg - ICP less than 15 mmHg[cite: 209

What physiological factors increase intracranial pressure?

Hypercapnia - Acidosis - Hypoxemia - Hyperthermia - Coughing - Shivering - Noxious stimuli[cite: 211]

What mechanical and positioning factors elevate ICP?

Lying flat - Extreme neck flexion - Tight tracheostomy ties - Tight cervical collars - Increased intra-abdominal or intrathoracic pressure[cite: 211]

What characterizes decorticate posturing and what is its GCS motor score?

Flexion of arms bent inward toward chest with balled fists and rigid extended legs scoring 3 on GCS motor response[cite: 207

What characterizes decerebrate posturing and what is its GCS motor score?

Rigid extension of arms parallel to body with flexed wrists curled fingers and extended legs scoring 2 on GCS motor response[cite: 207

What three vital sign changes constitute Cushing Triad?

Systolic hypertension with a widening pulse pressure - Bradycardia - Irregular respiratory pattern (such as Cheyne-Stokes)[cite: 212

What clinical signs indicate increased ICP in infants?

Bulging fontanels - Cranial suture separation - Increased head circumference - High-pitched cry[cite: 213

What are the major potential causes of increased ICP?

Mass lesions - Head trauma - Brain surgery - CNS infections - Vascular insults - CSF absorption/production alterations - Toxic/metabolic encephalopathy[cite: 214]

What lethal brain injury complication occurs when high ICP forces brain tissue downward or laterally through skull openings?

Cerebral herniation[cite: 215

What pathophysiology causes Diabetes Insipidus (DI) in neuro patients?

Inappropriately low ADH release leading to excretion of large volumes of dilute urine and severe dehydration[cite: 216]

What laboratory values confirm Diabetes Insipidus?

Urine specific gravity less than 1.005 - Serum osmolality greater than 295 mOsm/kg - Dilute urine output exceeding 200 mL per hour[cite: 216]

What key medications and interventions treat Diabetes Insipidus?

Administering synthetic ADH (Vasopressin or Desmopressin) and 1-to-1 fluid replacement for lost urine output[cite: 216]

What pathophysiology causes Syndrome of Inappropriate Antidiuretic Hormone (SIADH)?

Excessive release of ADH causing severe fluid retention hypervolemia and dilutional hyponatremia[cite: 217]

What laboratory values confirm SIADH?

Urine specific gravity greater than 1.025 - Serum osmolality less than 280 mOsm/kg - Severe hyponatremia[cite: 217]

What primary nursing interventions treat SIADH?

Fluid restriction (800 to 1000 mL per day) - Strict I and O - Monitoring electrolytes - Administering hypertonic saline or diuretics as ordered[cite: 217]

Why are patients with SIADH at high risk for life-threatening seizures?

Severe dilutional hyponatremia causing cerebral edema[cite: 217

What diagnostic imaging scan is the gold standard for evaluating acute brain trauma and increased ICP?

Head CT scan[cite: 219

Why are lumbar punctures strictly contraindicated in patients with suspected elevated ICP?

Risk of sudden brain herniation through the foramen magnum due to rapid pressure relief[cite: 219]

What blood test detects brain-specific proteins released within 12 hours of traumatic brain injury bleeding?

Brain Trauma Indicator (BTI)[cite: 219]

How should the head and bed be positioned to optimize venous drainage and lower ICP?

Keep head in a neutral midline alignment avoiding neck flexion with the head of bed elevated 30 to 45 degrees[cite: 220

Why is arterial PaCO2 strictly controlled in mechanically ventilated patients with high ICP?

Carbon dioxide is a potent cerebral vasodilator - keeping PaCO2 in the low normal range (35 to 38 mmHg) causes vasoconstriction and decreases ICP[cite: 220

What hyperosmolar agent is administered IV to pull fluid from brain tissue into the vascular space to reduce ICP?

Mannitol or 3 percent Hypertonic Saline[cite: 220

Where should the external transducer of an External Ventricular Drain (EVD) be leveled?

Leveled with the tragus of the ear or the external auditory meatus (corresponding to the Foramen of Monro)[cite: 222

What is the most critical life-threatening risk associated with an External Ventricular Drain (EVD)?

Infection leading to severe bacterial meningitis[cite: 223

What physical test confirms whether fluid leaking from the nose or ears is CSF?

Testing the drainage for the presence of glucose[cite: 224]

What physical activities and maneuvers must be avoided in a patient with elevated ICP?

Valsalva maneuvers - Turning the neck - Coughing - Deep breathing - Endotracheal suctioning unless necessary[cite: 225]

What target ABG arterial values are maintained for a TBI patient on mechanical ventilation?

PaO2 80 to 100 mmHg and PaCO2 35 to 38 mmHg[cite: 226]