Final Exam Study Guide Critical Care

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Apr 3, 2024

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NEURO (12 questions) Monro-Kellie Doctrine: ● Rigid, limited space (closed vault) ● Content: 80% brain, 10% cerebral blood volume, 10% CSF ● If volume increases in one compartment, then one or both of the others must decrease/comply Cerebral Blood Flow Without adequate blood flow we have loss of membrane integrity → ECF into the cell = cellular edema Autoregulation ● Ability of cerebral vessels to adjust diameter to pressure changes in the brain ○ CO2 = vasodilation in the brain ○ PO2 = vasoconstriction in the brain due to autoregulation Cushing’s Response: the brain’s attempt to restore blood flow by increasing arterial pressure to overcome increased intracranial pressure. Decompensation Phase: exhibit changes in mental status + V/S Cushing’s Triad ● Bradycardia ● Widening pulse pressure / hypertension ● Respiratory changes Herniation of brain stem + occlusion of cerebral blood flow + cerebral ischemia + infarction = leading to brain death Cerebral Perfusion Pressure (CPP) CPP = MAP - ICP (normal = 60-70 mmHg) Focused Neuro Assessment: Q 1 hour Glasgow Coma Scale (GCS) ● Mild injury: 13-15 ● Moderate injury: 9-12 ● Severe injury: < 8 Classification of Abnormal Motor Function ● Spontaneous: occurs without regard to external stimuli and may not occur by request ● Localization: occurs when extremity opposite to extremity receiving painful stimuli crosses the midline of the body in an attempt to remove the noxious stimulus from the affected limb ● Withdrawal: occurs when extremity receiving the painful stimulus flexes normally in an attempt to avoid the noxious stimulus ● Decortication: (think “core”) abnormal flexion response that may occur spontaneously or in response to noxious stimuli ● Decerebration: abnormal extension response that may occur spontaneously or in response to noxious stimuli ● Flaccid: no response to painful stimuli Protective Reflexes (indicating brainstem function) ● Corneal / blink ● Gag reflex ● Swallowing reflex ● Cough reflex

Oculocephalic Reflex (doll’s eyes) ● The eyes move in the opposite direction you turn the head ● Awake person - dolls eyes reflex not present ● Comatose person - this reflex IS normal ● Absent dolls eyes reflex in a comatose patient is BAD. indicates brainstem dysfunction. Damage in pons and/or medulla Oculovestibular Reflex (cold caloric/ iced caloric) ● Normal: pt will look toward the ear injected ● Absent reflex: BAD sign, usually a lesion in the pons or medulla ● Abnormal: look away or opposite, if patient partially awake Intracranial pressure (ICP) monitoring via a ventriculostomy ● Combination of the 3 compartment volumes ● Measured by the pressure exerted by the CSF within the ventricles of the brain ● Normal = 0-15 mmHg ● dynamic/fluctuates Intracranial Pressure (ICP) ● ICP greater than 20mmHg for more than 5 mins = problem ● Complete ischemia for >3-5 mins results in irreversible brain damage ● CO2 concentration regulates cerebral blood flow -- rise causes dilated whereas a fall vasoconstricts Possible indications for ICP monitoring: - Trauma, TBI - Stroke - Brain tumor - Post-cardiac arrest - Craniotomy - Coma - Subarachnoid hemorrhage - Systemic infarction - Hydrocephalus Contraindication for ICP monitoring: - Coagulopathy - Systemic infection - CNS infection - Infection at the site of device insertion Types of monitoring systems: ● Intraventricular (ventriculostomy)* ● Subarachnoid ● Epidural/subdural ● Intraparenchymal (fiber optic transducer tipped catheter) ZERO SYSTEM AT THE LEVEL OF THE TRAGUS ● The return drainage buretrol to the ordered number of cm of pressure ● Remember this is a gravity driven drainage system

Nursing measures for ICP monitoring ● sedation/analgesia ● Neuro assessments (hourly and PRN) ● VS/temps ● Monitor drainage, ICP/CPP, waveforms, system/tubing, insertion site ● Strict aseptic technique ● Know how high to have drainage system ● Drain CSF as ordered ● level/zero ● Notify physician when appropriate ● Meds ● Labs: Naa+ and serum osmolality levels, coags Causes of IICP ● Increased brain volume: cerebral edema, mass (tumor) ● Increased cerebral spinal fluid (CSF): hydrocephalus ● Increased CBF: impaired autoregulation, reactivity to increased O2 and CO2, hyperthermia, vasoactive drugs, anesthetic agents, physical activity, pain/noxious stimuli, seizures, infection (meningitis), increased intrathoracic pressure, increased intraabdominal pressure Assessment and diagnosis of intracranial hypertension ● Early symptoms: ○ Decreased LOC (earliest) ○ Vomiting / headache ● Late signs: ○ Decreased pupil reaction to light and unequal pupil size ○ Cushing’s triad (herniation) ○ Diminished brainstem reflexes ○ Abnormal flexion (decorticate posturing) ○ Abnormal extension (decerebrate posturing) ○ Change in resp patterns Nursing measures aimed at decreasing / managing ICP and controlling metabolic demand: ● Reduce noxious stimuli ○ Calm, quiet, dark room (low stim), pain/pressure ● Proper patient positioning, HOB 30 degrees ● Keep normothermic ● Sedation -- propofol*** (watch benzo’s-alter neuro exam) ● Osmotherapy -- mannitol ● CSF drainage -- open vs closed ● Barbiturate therapy -- phenobarb coma, maybe ● Maintain CPP ● Hypertonic saline (3%) IV via central line ● Patient care activities (cluster care) *** Management of intracranial hypertension: Cerebrospinal fluid drainage management ● Ventriculostomy / VP shunt ● Pliable catheter into anterior horn of lateral ventricle ● CSF drainage ● Monitoring device for ICP ● Treatment to lower ICP, BP control, seizure control ● Aseptic technique ● Maximize CPP ○ Diuretics and vol maintenance (osmotic diuretics -- mannitol, non osmotic diuretics -- furosemide / lasix) ○ Hypertonic (3% NSS) ○ Serum osmolality 300-320 mOsm/kg (275 to 295 mOsm/kg) ○ Fluid vol maintenance (limited) - Therapy aimed at reducing volume of one or more of the components - Head elevation positioning - now it is individualized to minimize ICP and maximize MAP (used to bee 30 degrees) - Avoid positions that decrease venous return from the brain

Types of brain bleeds ● Subdural: usually a venous bleed ● Epidural bleed: arterial bleed-fast decompensation (middle meningeal artery), can be venous-slower onset of symptoms Coup- contrecoup mechanism of injury: usually after blunt trauma. Site of impact from brain hitting opposite side of skull. The head strikes the wall (coup), then rebounds (countercoup) Skull fractures: - Linear - Depressed - Comminuted - Basilar (racoon eyes and battle sign) **monitor for CSF drainage (nose and ears) Care of the patient with a TBI Assessment: - GCS - Pupillary response - Motor function - Vital signs - Reflexes /pain - Brainstem function if required - Respiratory Diagnostics - CT - MRI/MRA - Transcranial doppler - EEG - Angiography Vital signs in TBI - Hyperdynamic state - Increased BP, HR, CO - Cushing’s triad - Elevated BP, bradycardia, irregular respirations - Impaired autoregulation Medical management of TBI - Stabilize vital signs - Reduce increases in ICP and maintain adequate cerebral perfusion pressure - Always be ready to travel to CT or OR emergently - Fluid resuscitation*** - Evacuation of lesion/mass/bleed - Early intubation - Management of secondary injuries

Craniotomy Pre-op - Document baseline neuro assessment - Blood tests, type and cross match - Chest x-ray and 12 lead ECG - Teaching: avoid activities known to increase ICP - FFP prior to OR Post - op - Varies depending on underlying reason for craniotomy - Management directed at prevention of complications (intracranial HTN, surgical hemorrhage, fluid imbalance, CSF leak, DVT prophylaxis Complications of TBI Diabetes Insipidus (DI) - Traumatic injury to the posterior pituitary or hypothalamus. Deficiency of the ADH - DI is HIGH - High urine output SIADH (syndrome of inappropriate antidiuretic hormone) - Producing too much ADH - SIADH is LOW - Na < 135 (severity related to how depleted) - Low to NO urine output and concentrated Cerebral vascular accident - CVA or stroke - Impaired blood flow - Third leading cause of death, leading cause of serious long-term disability - Ischemic (brain attack) vs hemorrhagic Assessment and diagnosis: - Sudden onset of focal neurological signs lasting >24hrs - CT scan, ECG, CXR, echo, jjjjjjjjj coags, electrolytes, glucose, jjjjjjjjjj renal/hepatic function, ABGs, jjjjjjjjjj EEG,LP Medical management ● Thrombolytic therapy -- within 4.5 hours of onset or ischemic strokes ● Airway management ● BP control, temp, glucose managment ○ Thrombolytic indications: ■ Acute ischemic stroke 4.5 hours from symptom onset ■ Greater than 18 years of age ○ Thrombolytic contraindications: ■ Intracranial hmorrhage ■ Recent stroke/head trauma ■ Uncontrolled HTN at time of treatment ■ Seizure at time of symptoms ■ A-V malformation, neoplasm, anurysm ■ Abnormal labs Subarachnoid Hemorrhage (SAH) ● SAH usually caused by a ruptured aneurysm or arterio-venous malformation (AVM) ● Accounts for approx. 4.5 - 13% of strokes

● More common in women Assessment and diagnosis of SAH ● “Worst headache of my life!” ● Thunderclap HA-peaks within 60 seconds ● LOC, n/v, focal neuro defects, stiff neck ● s/s indicative of “warning leaks” -- take a good history ● CT scan, LP, Cerebral angiography Medical Management ● Medical emergency ● airway/ventilation ● Support VS ● Ventriculostomy ● rebleeding , cerebral vasospasm ○ (CV) onset is usually 4-10 days after initial hemorrhage ○ Nimodipine ○ Cerebral angioplasty Managing Rebleeding - BP control - Aneurysm clipping, coil, medicinal glue, gamma knife, embolization - Anterio-venus malformation excision COMA Structural / surgical - Trauma - Intracerebral hemorrhage - Hydrocephalus - Ischemic stroke - Tumor Metabolic / medical - Infection - Endocrine disorders - Encephalopathy - Intoxication - Drug overdose - Poisonings - Meningitis - Encephalitis Coma collab. Management: - Treat underlying cause - Protect airway - Support circulation - Frequent q1 hr neuro exam - Nutrition - Eye care - Skin integrity - Monitor for complications - Comfort / emotional support - Plan for rehab program early - Education family recovery / rehab phase - long

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