NLE Neurosensory Nursing — Neurologic Assessment and DiagnosticsDetailed Explanation

Neurophysiology Review: CNS, PNS, and the Monro-Kellie Doctrine

The nervous system has two main divisions. The Central Nervous System (CNS) consists of the brain and spinal cord — the 'command center.' The Peripheral Nervous System (PNS) includes all cranial nerves, spinal nerves, and the autonomic nervous system (ANS), which connects the CNS to the rest of the body. The brain itself has three major regions: 1. Cerebrum — responsible for higher functions (thinking, memory, speech, voluntary movement, sensation). The left hemisphere generally controls language and is dominant in most people; the right hemisphere governs spatial skills and creativity. 2. Cerebellum — coordinates smooth movement, balance, and posture. Think of it as the 'editor' that fine-tunes your movements. 3. Brainstem (midbrain, pons, medulla) — controls vital, life-sustaining functions: respiration, heart rate, blood pressure, and consciousness through the Reticular Activating System (RAS). The medulla is the most critical — damage here is fatal. The Monro-Kellie Doctrine is a foundational concept for understanding why brain injuries become dangerous so quickly. The skull is a rigid, non-expandable box. Inside it, three components share a fixed total volume: - Brain tissue: approximately 80% - Blood: approximately 10% - Cerebrospinal fluid (CSF): approximately 10% If any one component increases in volume (e.g., a bleeding tumor, cerebral edema), the other components must decrease to compensate. Initially, the brain shifts CSF out and reduces blood volume. But once these compensatory mechanisms are exhausted, intracranial pressure (ICP) rises sharply and dangerously. Cerebral Perfusion Pressure (CPP) is the pressure pushing oxygenated blood into the brain. The formula is: CPP = MAP − ICP Where MAP = mean arterial pressure. - Normal CPP: 60–100 mmHg - CPP < 50 mmHg: cerebral ischemia begins - CPP < 30 mmHg: incompatible with viable brain tissue (brain death territory) - Normal ICP: 5–15 mmHg in adults In a Philippine tertiary hospital setting, ICP monitoring is done in ICU patients with severe head injury (GCS ≤ 8) to guide interventions like osmotic therapy (mannitol), CSF drainage, and positioning.

Level of Consciousness (LOC) Assessment

Level of consciousness (LOC) is the single most sensitive indicator of neurologic change. A declining LOC is an early warning sign that precedes changes in vital signs and pupils — making it the 'first alarm' in neurologic deterioration. Under the nursing process, assessing LOC is a priority assessment (Maslow: physiological safety need). LOC exists on a continuum from fully alert to deeply comatose: 1. Alert — fully awake, oriented, responds normally to all stimuli 2. Lethargic (Somnolent) — drowsy but can be aroused with normal verbal stimulation; returns to drowsiness when stimulation stops 3. Obtunded — difficult to arouse; requires repeated or loud verbal stimulation; slow, confused responses 4. Stuporous — arouses only to vigorous or painful stimulation; minimal purposeful response; returns immediately to unresponsiveness 5. Comatose — no purposeful response to any stimulation, including pain Orientation is assessed in three dimensions: person (knows their own name), place (knows where they are), and time (knows the date, day, month, year). Document as 'oriented x3' or specify: 'oriented to person and place only (disoriented to time).' Always describe the specific stimulus used and the exact response observed — vague labels like 'semi-conscious' are not acceptable in professional nursing documentation. In the Philippine clinical setting, nurses document LOC in the nurses' notes and vital signs flow sheet. Per RA 9173, accurate and timely documentation is a professional nursing responsibility. Any acute change in LOC must be reported to the physician immediately.

Glasgow Coma Scale (GCS)

The Glasgow Coma Scale (GCS) is the most widely used standardized tool for objectively measuring consciousness. It was developed in 1974 by Teasdale and Jennett and is now a universal standard in neurologic assessment. The NLE frequently tests GCS scoring, interpretation, and clinical decision-making based on GCS scores. The GCS measures three behavioral responses and assigns a numerical score to each: 1. EYE OPENING (E) — scored 1 to 4: - 4 = Spontaneous (opens eyes without any stimulus) - 3 = To voice (opens eyes when spoken to) - 2 = To pain (opens eyes only when painful stimulus is applied, e.g., supraorbital pressure, sternal rub) - 1 = None (no eye opening to any stimulus) 2. VERBAL RESPONSE (V) — scored 1 to 5: - 5 = Oriented (knows person, place, time — answers coherently) - 4 = Confused (carries on a conversation but gives incorrect answers about orientation) - 3 = Inappropriate words (uses random words, often expletives, not in conversational context) - 2 = Incomprehensible sounds (moans, groans — no recognizable words) - 1 = None (no verbal output) 3. BEST MOTOR RESPONSE (M) — scored 1 to 6: - 6 = Obeys commands (follows two-step verbal commands, e.g., 'Hold up two fingers') - 5 = Localizes to pain (brings hand toward the painful stimulus to push it away) - 4 = Withdraws from pain (pulls limb away from pain — nonspecific withdrawal) - 3 = Abnormal flexion / Decorticate (arms flex toward core, legs extend) - 2 = Abnormal extension / Decerebrate (arms extend and pronate rigidly, legs extend) - 1 = None (flaccid — no motor response) TOTAL GCS = E + V + M (minimum 3, maximum 15) A normal, fully alert person scores E4 + V5 + M6 = 15. CLINICAL INTERPRETATION OF TOTAL SCORE: - 13–15 = Mild impairment (GCS 15 = normal) - 9–12 = Moderate impairment - 3–8 = Severe impairment / Coma CRITICAL THRESHOLD: GCS ≤ 8 = COMA. A GCS of 8 or less is the standard threshold for endotracheal intubation to protect the airway from aspiration. This is a classic NLE question. A drop of 2 or more GCS points is clinically significant — report and act immediately. MOTOR POSTURING (Critical Distinction): - DECORTICATE POSTURING (Score M3 — Abnormal Flexion): Arms are FLEXED and drawn toward the chest/core; legs are extended and internally rotated. This indicates damage above the brainstem — at the level of the cerebral hemispheres or internal capsule. Think 'DE-COR-ticate = toward the CORE.' - DECEREBRATE POSTURING (Score M2 — Abnormal Extension): Arms are EXTENDED, rigidly pronated (palms down), and legs are extended. This indicates damage at or below the midbrain/upper pons (brainstem level). This is MORE SERIOUS than decorticate. - Progression from decorticate → decerebrate is an OMINOUS sign of worsening brainstem compression. Report immediately.

Pupillary and Cranial Nerve Assessment

Pupillary assessment is a critical component of every neuro check. Pupils are assessed for four characteristics using the mnemonic PERLA: Size, Equality, Roundness (shape), and Light Reactivity (brisk vs. sluggish vs. absent). NORMAL PUPILS: Equal, Round, Reactive to Light, 2–6 mm in diameter (often abbreviated PERRLA — 'A' for Accommodation, though this is rarely tested clinically). CLINICALLY SIGNIFICANT PUPIL CHANGES: 1. Unilateral fixed, dilated ('blown') pupil — ONE pupil is large (6–8 mm), fixed (does not constrict to light), and round. This is a NEUROLOGIC EMERGENCY. It indicates uncal herniation compressing Cranial Nerve III (Oculomotor nerve) on the same side (ipsilateral). The uncus (inner part of the temporal lobe) herniates downward through the tentorial notch and compresses CN III. Report immediately and prepare for urgent intervention. This is a classic NLE scenario. 2. Bilateral fixed and dilated pupils — Both pupils are large and non-reactive. This indicates severe midbrain damage or end-stage herniation. The prognosis is grave (associated with brain death). 3. Pinpoint pupils (miosis) — Very small pupils (1–2 mm). Causes include pontine lesion (hemorrhage or infarct compressing the pons) or opioid toxicity/overdose. In Philippine ER settings, pinpoint pupils in an unconscious patient — consider naloxone (Narcan) administration for opioid overdose. 4. Unequal pupils (Anisocoria) — pupil asymmetry greater than 1 mm, especially if new, is abnormal and requires urgent neurologic evaluation. THE 12 CRANIAL NERVES — COMPLETE REVIEW: Memorize names using: 'On Old Olympus' Towering Tops, A Finn And German Viewed Some Hops.' I=Olfactory, II=Optic, III=Oculomotor, IV=Trochlear, V=Trigeminal, VI=Abducens, VII=Facial, VIII=Vestibulocochlear (Acoustic), IX=Glossopharyngeal, X=Vagus, XI=Spinal Accessory, XII=Hypoglossal. Function types — mnemonic: 'Some Say Money Matters But My Brother Says Big Brains Make Money' (S=Sensory, M=Motor, B=Both): CN I: Sensory — smell CN II: Sensory — visual acuity, visual fields CN III: Motor/Both — pupil constriction, eyelid elevation, most extraocular movements; DAMAGED in herniation = blown pupil + ptosis CN IV: Motor — downward/inward eye movement (trochlear = superior oblique muscle) CN V: Both — facial sensation (sensory) + jaw/mastication muscles (motor); sensory limb of the corneal reflex CN VI: Motor — lateral eye gaze (abducens = lateral rectus); 6th nerve palsy = unable to look laterally, eye turns medially CN VII: Both — facial expression (motor); taste anterior 2/3 tongue (sensory); MOTOR limb of the corneal reflex (blink) CN VIII: Sensory — hearing and balance/equilibrium CN IX: Both — taste posterior tongue, pharyngeal sensation, swallowing; gag reflex (sensory limb) CN X: Both — swallowing, phonation (voice), gag reflex (motor limb), parasympathetic to thoracic/abdominal organs CN XI: Motor — shoulder shrug (trapezius) and head turning (sternocleidomastoid) CN XII: Motor — tongue movement (assessed by asking patient to protrude tongue; deviation toward side of lesion) CORNEAL REFLEX: Touching the cornea with a wisp of cotton. - Sensory (afferent) limb = CN V (Trigeminal) - Motor (efferent/response) limb = CN VII (Facial) → produces blink This reflex is used in unconscious patients to test brainstem integrity.

Motor, Sensory, and Reflex Testing

A complete neurologic examination includes testing motor function, sensory function, coordination, and deep tendon reflexes. These assessments help localize the lesion (where in the nervous system the damage is). MOTOR FUNCTION GRADING (Medical Research Council Scale, 0–5): - Grade 0: No muscle contraction visible or palpable (complete paralysis) - Grade 1: Flicker or trace of contraction — visible but no joint movement - Grade 2: Active movement with gravity eliminated (limb can move horizontally on a surface) - Grade 3: Active movement against gravity only (can lift limb off the bed) - Grade 4: Active movement against some resistance (not full strength) - Grade 5: Normal strength — moves against full resistance PRONATOR DRIFT TEST: A sensitive test for subtle upper limb weakness. Ask the patient to extend both arms forward with palms up and close eyes. Hold for 10–15 seconds. If one arm drifts downward or pronates (turns palm down), this indicates contralateral upper motor neuron weakness. A positive pronator drift can be the earliest sign of a corticospinal tract lesion. COORDINATION TESTS: - Finger-to-Nose Test: Patient touches their nose then the examiner's finger repeatedly. Cerebellar damage causes dysmetria (missing the target) and intention tremor. - Heel-to-Shin Test: Supine patient runs the heel of one foot down the shin of the opposite leg. Ataxia or incoordination indicates cerebellar dysfunction. - Gait Assessment: Ataxic gait (wide-based, unsteady) = cerebellar problem. Hemiplegic gait (circumduction) = corticospinal tract lesion. SENSORY TESTING: - Light touch (anterior spinothalamic tract) - Pain and temperature (lateral spinothalamic tract) - Vibration and proprioception (dorsal columns) Sensory deficits help determine the level and side of the spinal cord lesion. DEEP TENDON REFLEXES (DTR) — Graded 0 to 4+: - 0 = Absent - 1+ = Diminished - 2+ = Normal - 3+ = Brisk/Hyperactive - 4+ = Hyperactive with clonus (rhythmic, involuntary contractions) Hyperactive reflexes (3+, 4+) = Upper Motor Neuron (UMN) lesion (brain or spinal cord) Absent/diminished reflexes (0, 1+) = Lower Motor Neuron (LMN) lesion (peripheral nerves) BABINSKI REFLEX (Plantar Reflex): - How to test: Stroke the lateral sole of the foot from the heel toward the toes (use a key, wooden end of a reflex hammer, or tongue depressor). - NORMAL RESPONSE IN ADULTS: Plantar flexion of the great toe (toe curls downward) — this is NEGATIVE Babinski. - ABNORMAL RESPONSE IN ADULTS (POSITIVE BABINSKI): The great toe dorsiflexes (goes UP) and the other toes fan out. This is a sign of an UPPER MOTOR NEURON LESION (damage to the corticospinal/pyramidal tract in the brain or spinal cord). - IMPORTANT: Positive Babinski is NORMAL in infants under 2 years old (because myelination of corticospinal tracts is incomplete). It becomes ABNORMAL when it persists beyond age 2. - The Babinski is one of the most frequently tested reflexes in the NLE.

Cushing's Triad and Neuro Vital Signs

SERIAL NEURO CHECKS ('Neuro Vitals') are a structured set of nursing assessments performed at regular intervals for patients at risk of neurologic deterioration. In Philippine hospitals, this is standard of care in neurosurgical ICUs, stroke units, and wards. Per RA 9173, the nurse is professionally and legally responsible for accurate and timely monitoring. A complete neuro check includes: 1. Level of Consciousness (LOC) 2. Glasgow Coma Scale (GCS) score 3. Pupil size, equality, and light reactivity 4. Motor and sensory function (limb movement, grip strength) 5. Vital signs (BP, HR, RR, temperature, SpO2) Frequency: Every 4 hours for stable patients; every 1–2 hours or more frequently for unstable patients. Escalation frequency = escalating risk. CUSHING'S TRIAD: This is THE classic late sign of dangerously elevated ICP and impending brainstem herniation. It consists of THREE components: 1. RISING SYSTOLIC BLOOD PRESSURE with a WIDENING PULSE PRESSURE - The body attempts to maintain cerebral perfusion by increasing systemic BP to overcome the high ICP - Example: BP rises from 120/80 (pulse pressure 40) to 180/60 (pulse pressure 120 — wide!) - This is the Cushing reflex — the brain's last-ditch attempt to perfuse itself 2. BRADYCARDIA (slow heart rate) - Reflex bradycardia occurs in response to the rising BP (baroreceptor-mediated) - HR drops from 80 to 50 or lower 3. IRREGULAR RESPIRATIONS - As the brainstem (medulla/respiratory center) is compressed, respiratory patterns become abnormal - Patterns: Cheyne-Stokes breathing (crescendo-decrescendo pattern with apnea), Central Neurogenic Hyperventilation, Ataxic breathing (completely irregular — very ominous sign) CUSHING'S TRIAD IS A LATE SIGN — by the time it appears, herniation is imminent or occurring. This is why EARLY detection through serial LOC and GCS monitoring is emphasized. MEMORY TIP: 'The brain is RISING the BP to save itself, SLOWING the heart, and LOSING control of breathing.' RISING TEMPERATURE: May indicate hypothalamic involvement (the hypothalamus controls thermoregulation) or infection (meningitis, ventriculitis). Hyperthermia increases cerebral metabolic rate and worsens brain injury — treat aggressively with antipyretics and cooling measures. NURSING INTERVENTIONS FOR INCREASED ICP: - Elevate HOB 30–45 degrees - Keep head and neck in neutral alignment (avoid neck flexion or rotation) - Avoid suctioning longer than 10–15 seconds (stimulates Valsalva and increases ICP) - Minimize stimulation (dim lights, reduce noise, cluster care) - Administer prescribed osmotic diuretics (mannitol) or hypertonic saline - Prepare for emergency CSF drainage (ventriculostomy)

CT Scan, MRI, and Neurodiagnostic Imaging

Neurodiagnostic imaging is essential for diagnosing structural brain and spinal cord pathology. The nurse's role includes patient preparation, safety screening, post-procedure care, and patient education. COMPUTED TOMOGRAPHY (CT SCAN): - Mechanism: Uses X-rays to produce cross-sectional images of the brain. Fast (minutes), widely available, no MRI contraindications. - First-line emergency study: CT is the GOLD STANDARD for the ACUTE emergency setting because it is FAST and excellent at detecting: * Acute hemorrhage (blood appears BRIGHT WHITE / hyperdense on CT) * Skull fractures * Mass effect (midline shift due to tumor, hematoma, or edema) * Hydrocephalus - Stroke protocol: CT head is done IMMEDIATELY in all suspected stroke patients to DISTINGUISH hemorrhagic from ischemic stroke — because treatment is OPPOSITE: ischemic stroke = thrombolytics (tPA); hemorrhagic stroke = tPA is CONTRAINDICATED. - Contrast CT: Iodine-based contrast enhances blood vessels and tumors. NURSING CONSIDERATIONS: * Assess for iodine/shellfish allergy (risk of anaphylaxis) * Assess renal function (creatinine/BUN) — contrast is nephrotoxic * Hydrate well before and after * Withhold metformin 48 hours before and after contrast (risk of lactic acidosis) * Assess for and treat anxiety/claustrophobia (less common in CT vs. MRI but still possible) MAGNETIC RESONANCE IMAGING (MRI): - Mechanism: Uses powerful magnetic fields and radiofrequency waves (NO radiation). Provides superior soft-tissue contrast compared to CT. - MRI is BETTER THAN CT for: * Early ischemic stroke (within first few hours before CT changes appear) * Brain tumors (better delineation of margins) * Demyelinating diseases (multiple sclerosis — white matter plaques) * Posterior fossa (cerebellum, brainstem) — CT has artifact in this area * Spinal cord pathology - MRI CONTRAINDICATIONS and SAFETY SCREENING — CRITICAL NURSING RESPONSIBILITY: * Pacemakers or implantable cardiac defibrillators (ICDs) — ABSOLUTE contraindication (magnet can deactivate/reprogram) * Ferromagnetic metal implants — cerebral aneurysm clips (older types), cochlear implants, orbital foreign bodies * Joint replacements (titanium = usually safe; older stainless steel = unsafe) * Insulin pumps, neurostimulators * REMOVE ALL METAL: jewelry, hairpins, hearing aids, clothing with metal fasteners, credit cards, phones - CLAUSTROPHOBIA: The MRI bore (tube) is narrow and LOUD. Assess for claustrophobia; anxiolytic premedication may be ordered. Open MRI is available for severe cases. - GADOLINIUM contrast (used in MRI): Monitor for nephrogenic systemic fibrosis in patients with renal failure. CEREBRAL ANGIOGRAPHY: - Invasive procedure using contrast to visualize cerebral blood vessels - Used for: cerebral aneurysms, arteriovenous malformations (AVM), vasospasm post-subarachnoid hemorrhage - Care is similar to cardiac catheterization: * Pre-procedure: allergy and renal screening, consent, NPO, mark peripheral pulses * Post-procedure: monitor puncture site (femoral or radial), hourly neuro and pulse checks, bed rest if femoral approach, adequate hydration to flush contrast

Lumbar Puncture (LP)

A lumbar puncture (LP), also called a spinal tap, is an invasive procedure that involves inserting a needle into the subarachnoid space to collect cerebrospinal fluid (CSF) for diagnostic analysis or to measure CSF pressure. INDICATIONS: - Suspected meningitis or encephalitis (to identify the organism) - Subarachnoid hemorrhage (SAH) — if CT is negative but SAH still suspected (xanthochromia) - Diagnosis of multiple sclerosis (oligoclonal bands, IgG index) - Measurement of opening pressure - Intrathecal drug administration (spinal anesthesia, chemotherapy, antibiotics) ANATOMY — CRITICAL FOR NLE: - LP is performed at L3–L4 or L4–L5 (either interspace is acceptable) - Why below L1–L2? The spinal cord ends at approximately L1–L2 (conus medullaris). Below this level is the cauda equina (a bundle of nerve roots that float in CSF). A needle at L3–L4 or L4–L5 enters the subarachnoid space WITHOUT penetrating the cord — making it safe. CONTRAINDICATION: LP IS CONTRAINDICATED WHEN ICP IS ELEVATED (INCREASED INTRACRANIAL PRESSURE). This is the most critical LP contraindication. When ICP is high, a sudden release of pressure at the lumbar level creates a pressure gradient that can pull the brainstem downward through the foramen magnum — this is called TRANSTENTORIAL or TONSILLAR HERNIATION — and it is FATAL. A CT scan should always be done BEFORE LP if there is any clinical concern about elevated ICP (papilledema, declining LOC, focal deficits). Other contraindications: infection at the puncture site, coagulopathy/bleeding disorders, thrombocytopenia. NORMAL CSF CHARACTERISTICS: - Color: CLEAR AND COLORLESS (like water) - Pressure: 7–20 cmH2O (opening pressure) - Protein: 15–45 mg/dL - Glucose: 45–80 mg/dL (approximately 60–70% of blood glucose) - WBC: 0–5 cells/mm3 (all mononuclear) ABNORMAL CSF FINDINGS: - Cloudy/turbid = bacterial infection (increased WBCs, protein) - Bloody = subarachnoid hemorrhage (blood present) - Xanthochromic (yellow) = old blood breakdown (hemoglobin oxidized to bilirubin) — indicates SAH occurred hours to days earlier (differentiates true SAH from traumatic tap) - Increased protein = meningitis, Guillain-Barré syndrome - Decreased glucose = bacterial meningitis (bacteria consume glucose) - Increased WBCs = infection or inflammation NURSING CARE FOR LUMBAR PUNCTURE: BEFORE THE PROCEDURE: 1. Obtain informed consent (physician's responsibility; nurse ensures it is obtained per RA 9173) 2. Verify no contraindications (especially no elevated ICP — check CT results) 3. Position the patient: LATERAL DECUBITUS (side-lying) with knees drawn to chest and chin tucked (FETAL/EMBRYO POSITION) — OR sitting upright with spine curved forward. The purpose is to WIDEN the intervertebral spaces for easier needle insertion. 4. Maintain sterile technique throughout DURING THE PROCEDURE: - Support and comfort the patient — reassure and remind to stay still - Monitor vital signs and neurologic status - Label CSF specimens in order (tubes 1, 2, 3, 4) — order matters for interpretation AFTER THE PROCEDURE (Critical Nursing Care): 1. POSITION: Keep the patient LYING FLAT (supine) for 1–4 hours (or as ordered). The rationale: to equalize CSF pressure across the entire subarachnoid space and prevent CSF leakage from the puncture site. 2. ENCOURAGE FLUIDS: Increase oral fluid intake to promote CSF production and replace the volume removed — helps prevent post-LP headache. 3. MONITOR FOR POST-LP HEADACHE (Spinal Headache): Most common complication. Caused by CSF leakage through the dura at the puncture site, creating a low-pressure headache. Characteristics: severe, positional (worsens when sitting/standing, improves when lying flat). Treatment: bed rest, increased fluids, caffeine, analgesics. If severe, an EPIDURAL BLOOD PATCH may be performed. 4. Monitor for complications: infection (meningitis), hematoma, nerve root injury, and — most dangerously — herniation (if ICP was undetected).

Intracranial Pressure (ICP) Monitoring

ICP monitoring provides continuous measurement of intracranial pressure, allowing early detection of dangerous pressure elevations before clinical signs appear. It is indicated for patients with severe neurologic injury (GCS ≤ 8), significant head trauma, post-operative craniotomy patients, and others at high risk of intracranial hypertension. NORMAL ICP: 5–15 mmHg in adults (some sources say 7–15 mmHg). DANGEROUSLY ELEVATED ICP: > 20 mmHg requires treatment. TYPES OF ICP MONITORING DEVICES (from least to most invasive): 1. EPIDURAL SENSOR: Placed in the epidural space (between skull and dura). Least invasive, lowest infection risk. CANNOT drain CSF. 2. SUBARACHNOID BOLT: Placed through the dura into the subarachnoid space. Can measure pressure. CANNOT drain CSF. 3. PARENCHYMAL FIBER-OPTIC CATHETER: Placed directly into brain tissue (parenchyma). Accurate, minimal infection risk. CANNOT drain CSF. 4. INTRAVENTRICULAR CATHETER (VENTRICULOSTOMY / EXTERNAL VENTRICULAR DRAIN — EVD): This is the GOLD STANDARD. A catheter is inserted through the skull and brain tissue into the lateral ventricle (usually the right lateral ventricle — non-dominant hemisphere). It provides the MOST ACCURATE pressure readings AND allows THERAPEUTIC DRAINAGE OF CSF to lower ICP. This makes it the most functionally versatile device. KEY NURSING CARE FOR ICP MONITORING AND EVD: 1. TRANSDUCER LEVELING: The most critical nursing responsibility for accurate ICP readings. The transducer must be leveled at the FORAMEN OF MONRO — the drainage point between the lateral ventricles and the third ventricle. External landmarks: approximately at the level of the TRAGUS OF THE EAR or the OUTER CANTHUS OF THE EYE (both are at the level of the foramen of Monro). Each time the patient's head position changes, the transducer must be re-leveled. Incorrect leveling = inaccurate ICP readings. 2. MAINTAINING A CLOSED, STERILE SYSTEM: The EVD is a direct pathway into the brain — infection (ventriculitis/meningitis) is the most serious and feared complication. Strict aseptic technique is mandatory for all system manipulations (emptying, sampling, adding medications). Minimize disconnections. Monitor for signs of infection: fever, neck stiffness, changes in mental status. 3. MONITORING ICP WAVEFORMS: ICP displays a waveform with each cardiac cycle (like an arterial line). Three components: P1 (percussion wave), P2 (tidal wave), P3 (dicrotic wave). Normally P1 > P2 > P3. When P2 > P1, this indicates decreased intracranial compliance — the brain is less able to accommodate volume changes — a sign of worsening ICP dynamics. PLATEAU WAVES (A WAVES): Most dangerous type. Sudden, sustained ICP elevations to 50–100 mmHg lasting 5–20 minutes. They indicate severely reduced compliance and impending herniation. REPORT IMMEDIATELY. 4. PREVENTING FACTORS THAT INCREASE ICP: - Positioning: HOB at 30 degrees, neutral head/neck alignment (avoid flexion, rotation — these obstruct jugular venous drainage) - Avoid Valsalva maneuver (straining during defecation, coughing — use stool softeners) - Limit suctioning to < 15 seconds per pass; pre-oxygenate before suctioning - Minimize noxious stimulation; cluster care activities; allow rest periods - Prevent hypercapnia (CO2 causes cerebral vasodilation — raises ICP); maintain PaCO2 at 35–45 mmHg - Prevent hypoxia (SpO2 > 95%) - Treat fever aggressively (hyperthermia increases cerebral metabolic demand) 5. MEDICAL MANAGEMENT OF ELEVATED ICP (nurse implements and monitors): - Osmotic therapy: MANNITOL (IV) — osmotic diuretic that draws water from brain cells into the bloodstream. Monitor urine output, serum osmolality, electrolytes. - Hypertonic saline (3% NaCl) — also draws water from brain tissue - Controlled hyperventilation (short-term) — causes cerebral vasoconstriction, rapidly lowers ICP (PaCO2 target 30–35 mmHg temporarily) - Sedation and analgesia — reduce cerebral metabolic demand - Barbiturate coma (pentobarbital) in refractory cases — dramatically reduces cerebral metabolic rate - Surgical decompression (decompressive craniectomy)

Electroencephalography (EEG) and Cerebral Angiography

ELECTROENCEPHALOGRAPHY (EEG): An EEG records the brain's electrical activity through electrodes placed on the scalp. It measures voltage fluctuations from ionic currents in neurons. EEG is non-invasive, inexpensive, and widely available in Philippine tertiary hospitals. CLINICAL USES OF EEG: 1. SEIZURE DISORDERS: Primary use — differentiates seizure types, localizes seizure focus, classifies epilepsy syndrome, monitors treatment response 2. STATUS EPILEPTICUS monitoring: Continuous EEG (cEEG) in ICU patients to detect nonconvulsive status epilepticus 3. BRAIN DEATH CONFIRMATION: EEG shows electrocerebral silence (flat/isoelectric line) — one of the confirmatory tests for brain death 4. Encephalopathy evaluation: metabolic encephalopathy, herpes encephalitis 5. Sleep studies (polysomnography) NURSING CARE FOR EEG: BEFORE THE PROCEDURE: 1. HAIR PREPARATION: Hair must be CLEAN, DRY, and FREE OF OILS, SPRAYS, GEL, or CONDITIONER — these products interfere with electrode adherence and signal quality. Do NOT braid or put up the hair. 2. MEDICATIONS: Withhold STIMULANTS (caffeine-containing beverages: coffee, cola, energy drinks), SEDATIVES (unless otherwise ordered), and ANTISEIZURE MEDICATIONS as specifically ordered by the physician. Do NOT arbitrarily withhold antiseizure meds — only withhold if explicitly ordered. 3. Ensure the patient is RESTED (sleep deprivation may be intentionally requested in some protocols to provoke epileptiform activity) 4. Patient education: The procedure is painless; the electrodes measure electricity from the brain — they do NOT deliver electricity to the patient. DURING THE PROCEDURE: - Patient may be asked to hyperventilate (can trigger seizures) or look at flashing lights (photic stimulation) - Sleep induction may be requested AFTER THE PROCEDURE: - Remove electrode gel from hair - Resume normal medications - Patient may return to normal activities CEREBRAL ANGIOGRAPHY (CEREBRAL CATHETER ANGIOGRAPHY): - Also called digital subtraction angiography (DSA) - Gold standard for visualizing cerebral blood vessels - A catheter is inserted (usually via the femoral artery) and guided to cerebral vessels; iodine contrast is injected INDICATIONS: - Cerebral aneurysm diagnosis and pre-operative planning - Arteriovenous malformations (AVM) - Carotid stenosis assessment - Vasospasm post-SAH - Pre-embolization or coiling procedures NURSING CARE (similar to cardiac catheterization): BEFORE: - Obtain consent - Screen for iodine/shellfish allergy and renal function (contrast nephrotoxicity) - NPO for several hours - Baseline neuro check and peripheral pulse assessment (femoral or radial) - Mark distal pulses with a pen (dorsalis pedis, posterior tibial) AFTER: - Monitor the puncture site for bleeding, hematoma, or pseudo-aneurysm - Hourly pulse checks distal to the puncture site (if femoral approach: assess pedal pulses) - Bed rest per order (typically 4–6 hours if femoral approach) - Adequate hydration to flush contrast and prevent nephrotoxicity - Monitor neuro checks (contrast can occasionally cause neuro changes) - Watch for signs of allergic reaction to contrast

This problem tests all three GCS components simultaneously in a Filipino clinical context (EDSA motorcycle accident — a common mechanism in the Philippines). The M3 score (decorticate) indicates damage above the brainstem. GCS 9 = moderate severity. The nurse should be on high alert for further deterioration — a drop to GCS ≤ 8 requires immediate airway protection.

This scenario tests contraindication recognition AND professional advocacy. The nurse cannot simply 'follow orders' when the patient is at risk of harm. Per RA 9173, the nurse has a professional duty to question and clarify orders that may harm the patient. The declining GCS (from 13 to 10 — a drop of 3 points) adds urgency to the concern about elevated ICP.

This tests the CPP formula, interpretation, and nursing response. CPP = 53 is dangerously low — the brain is at risk of ischemia. The dual problem (low MAP + high ICP) requires a multi-pronged approach targeting BOTH components of the formula. In Philippine ICUs, this clinical scenario requires immediate team communication.

This comprehensive scenario integrates: GCS trending (progressive deterioration), pupil assessment (blown pupil = herniation), and Cushing's Triad (late ICP sign). In a single patient over 4 hours, all the high-yield neurologic emergency signs are present. The NLE may present this type of question as a 'what happens next' or 'priority action' scenario.

Post-angiography vascular complications are tested in the NLE. The '5 Ps' of arterial occlusion are key assessment findings. The nurse's role is early recognition and immediate escalation — delay can result in permanent limb ischemia.