Neuro Part 1 Flashcards
Levels of Consciousness
Alert
Confused
Lethargic
Obtunded: Arousable with stimulation, but sleepy. Follows simple commands
Stuporous: Very hard to arouse
Semicomatose: Purposeful movements
Comatose: Reflexive responses, no verbal responses
Decreased LOC: Nursing care
Avoid narcotics for pain to determine declining neuro status Airway Vital signs Neuro checks Protect eyes Nutrition Prevent skin breakdown Safety (Fall risk) Psychosocial
Oculocephalic reflex-Doll’s Eyes
Rotate patient’s head to one side and observe movement of eyes.
(NEVER do this if a C-spine injury is suspected)
Normal response—initial conjugate deviation of the eyes in the OPPOSITE DIRECTION, then in a few seconds, both eyes move back to midline.
Normal response indicates an intact brainstem.
Doll’s Eyes present: positive, a good thing, brainstem is intact
Oculovestibular reflex-caloric ice water test
Elevate head 30 degrees
Instill 30-50 mls iced water into ear (one at a time)
Patient MUST have intact eardrum and no skull fracture
Patient’s eyes should look TOWARD the irrigated ear
Shows intact midbrain and pons
*NEVER, EVER perform a lumbar puncture on a patient with elevated ICP or a patient who is coagulopathic!
Lumbar Puncture
Keep patient laying supine for 8-10 hours. Flat is best
Well hydrated
Check CSF for glucose, WBC’s, protein, infection, etc.
Increased Intracranial Pressure
Monroe-Kellie Hypothesis states that a change in volume of any one component must be accompanied by a reciprocal change in one or both of the other components. If this reciprocal change is not accomplished, the result is an increase in Intra-cranial Pressure (ICP).
Factors that influence ICP changes are:
Arterial & venous pressure Intra-abdominal and intra-thoracic pressure Posture Temperature Blood gases, particularly CO2 levels
Causes of increase in ICP:
Head trauma Stroke SAH Brain tumor Inflammation Hydrocephalus Brain tissue damage due to other causes
Clinical Manifestations of Increased ICP
**Changes in LOC: First sign
**Changes in VS
Sudden change in ICP - Cushing’s triad: Increased pulse pressure, decreased pulse, and changes in respiratory pattern with pupillary changes. Could be herniation of brain tissue.
Motor changes (contralateral)
Pupillary changes / Ocular signs (ipsilateral)
Headache/vomiting
***Respiratory pattern: Early sign (hyperventilate, low C02)
Complications of Increased ICP
Tissue ischemia
Tissue compression (herniation) When the structures of the brain are compressed, hormonal functions are affected:
***Diabetes insipidus (neurogenic) results when there is insufficient ADH released from the pituitary. Fluid and electrolyte imbalances occur. Causes increased urinary output with very low urine specific gravity and urine osmolality. Plasma osmolality is INCREASED due to hypernatremia and dehydration.
***Peeing a lot, replace fluids. Hypovolemic/hypotensive patients need preserved brain tissue, give fluids to compensate
Complications of Increased ICP: SIADH
SIADH- results when high ADH production occurs. Pt has fluid retention, low serum osmolality, dilutional hyponatremia, and concentrated urine and increased weight. They are ‘holding on’ to fluid.
Monitoring ICP
A catheter is placed into the brain that will give us a waveform and a pressure reading continuously.
Some systems allow CSF to be drained so that the pressure can be lowered.
***Hematoma, low GCS are indications for a ventricular catheter
Intracranial Pressure Monitoring
Normal ICP: 0-10, 15 is upper limit normal mm Hg
Sustained pressure >15 = abnormal
ICP HTN > 15 mmHg
Associated with increased risk of secondary brain damage
Locations for monitoring/measuring ICP
Subarachnoid Space - waveform is dampened due to the bone and tissue- no CSF drainage
Intraparenchymal- in the brain tissue, OK waveform but no CSF drainage
Intraventricular - gold standard. Excellent waveform and CSF drainage possible. High risk for infection.
Epidural space – Good waveform and CSF drainage is possible.
Managing elevated ICP
Mean Arterial Pressure (MAP)=Systolic BP+2(Diastolic BP) divided by 3
Cerebral Perfusion Pressure (CPP)—this tells us how well the brain is being perfused.
Normal CPP =70-80mmHg.
To calculate the CPP: CPP=MAP-ICP
CPP < 60mmHg there is a decrease in blood supply to the brain this will not provide adequate cerebral perfusion and oxygenation. neuronal hypoxia and cell death may occur.
CPP> 100 mmHG there is a potential for Hyperperfusion and increased ICP
Goal of Therapy -Reducing ICP:
**CSF drainage-no more than 30cc at a time
**Decrease edema with osmotic diuretics-Mannitol
**Proper positioning to optimize venous drainage-keep head and neck aligned and HOB elevated at 30 degrees
Preservation of cerebral oxygenation and perfusion
Early identification of neuro changes
Prevention of complications
**Surgical intervention-partial lobectomy to remove damaged tissue or hemicraniectomy (bone removed until edema resolved).
Pharmacological Management of ICP
Mannitol- powerful osmotic diuretic–can be given as intermittent IV boluses depending on the ICP. MUST monitor serum osmolarity, usually q6H (keep < 320mOsm or hypovolemia and renal failure occur).
IV hypertonic saline (1.8%, 3% or 7.5%). Also decreases brain tissue volume. Needs central line and EKG monitoring.
Continuous IV sedation
Possible neuromuscular blockade (NMB)
Possible barbiturate coma if all else fails (Phenobarbital)-decreases cerebral tissue demands
Anticonvulsants (Phenytoin or Fosphenytoin)
