3.4 Neurological Assessment: GCS, ACVPU & Acute Deterioration

2.3 Neurological Assessment: GCS, ACVPU & Acute Deterioration

Neurological assessment is a foundational nursing competency across acute medical, surgical, and emergency care settings in Ireland. Rapid identification of acute neurological decline enables timely intervention before irreversible cerebral herniation, ischaemic infarction, or secondary brain injury ensues. In clinical practice, the ACVPU scale provides rapid track-and-trigger triage within INEWS v2, while the Glasgow Coma Scale (GCS) delivers a detailed, quantitative, and longitudinal evaluation of impaired consciousness.

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1. The Glasgow Coma Scale (GCS): Structured Assessment

Devised by Teasdale and Jennett, the Glasgow Coma Scale (GCS) evaluates three independent behavioral domains: Eye Opening (E1–E4), Verbal Response (V1–V5), and Motor Response (M1–M6). Scores range from a minimum of 3 (deep coma/unresponsive) to a maximum of 15 (fully conscious).

The Standardized 4-Step Assessment Sequence

In accordance with updated international and Irish neuro-nursing standards, every GCS evaluation must proceed through four structured steps:

1. Check: Verify pre-existing factors interfering with assessment (e.g., hearing impairment, dysphasia, endotracheal tube, orbital trauma, sedation, paralysis).
2. Observe: Inspect the patient for spontaneous behaviors (spontaneous eye opening, orientation, voluntary limb movement).
3. Stimulate: If spontaneous response is absent, apply an auditory stimulus (speak clearly or shout). If unresponsive to sound, apply standardized physical pressure (trapezius squeeze, supraorbital pressure, or fingernail bed pressure).
4. Rate: Score the patient's best response in each category.

Detailed Scoring Breakdown

Clinical Significance of GCS Thresholds

• GCS ≤ 8 ("GCS of eight, intubate"): Defines severe coma. Protective pharyngeal and laryngeal airway reflexes (cough, gag) are lost. Requires immediate emergency airway protection and endotracheal intubation.
• Acute Drop of ≥ 2 GCS Points: Defined across HSE neurotrauma guidelines as a critical neurosurgical emergency. Indicates acute intracranial decompensation (e.g., expanding intracranial haematoma, malignant cerebral oedema, acute hydrocephalus) and requires immediate escalation.

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2. Pupillary Assessment & Brainstem Integrity

Pupillary examination assesses the integrity of the autonomic nervous system and Cranial Nerve III (Oculomotor Nerve), which travels along the tentorial incisura.

Pupillary Reflex Protocol (PERRLA)

• Size (mm): Measure baseline diameter using a pupil gauge (normal: 2–5 mm). Equal size is normal; mild physiological anisocoria (<1 mm difference) occurs in 20% of the population.
• Shape: Pupils should be round and regular. Oval or peaked pupils suggest intraocular surgery or elevated ICP.
• Light Reactivity: Test both direct response (constriction of illuminated pupil) and consensual response (constriction of contralateral pupil).

Ominous Pupillary Findings

• Unilateral Fixed and Dilated Pupil ("Blown Pupil"): Compression of the ipsilateral oculomotor nerve (CN III) secondary to uncal/transtentorial herniation. Caused by an expanding supratentorial mass (e.g., epidural or subdural haematoma). This is a surgical emergency requiring immediate decompression.
• Bilateral Dilated and Unreactive Pupils: Indicates catastrophic severe brainstem hypoxia, bilateral uncal herniation, or imminent brain death.
• Bilateral Pinpoint Pupils (1–2 mm): Suggests acute pontine haemorrhage (interruption of descending sympathetic pathways) or opioid intoxication.

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3. Acute Stroke Assessment & Hyperacute Pathways

Acute stroke is a medical emergency where "time is brain". In Irish acute care, standard screening pathways ensure rapid triage to hyperacute stroke units.

Screening Tools: FAST & ROSIER

1. FAST Screening:
   • F (Face): Facial droop or asymmetry when smiling.
   • A (Arms): Arm weakness or downward drift when both arms are extended for 10 seconds.
   • S (Speech): Slurred speech, expressive aphasia, or difficulty finding words.
   • T (Time): Time of onset is critical; establish the exact last known well time.
2. ROSIER (Recognition of Stroke in the Emergency Room):
   • Validated acute screening tool that scores focal neurological signs (+1 each for asymmetric facial, arm, or leg weakness, speech disturbance, or visual field defect) while deducting points (-1 each) for loss of consciousness or seizures, distinguishing stroke from stroke mimics.

Hyperacute Stroke Pathways & Nursing Priorities

• Recombinant Tissue Plasminogen Activator (rtPA / Alteplase):
  • Must be administered within 4.5 hours of symptom onset in eligible patients with acute ischaemic stroke.
• Endovascular Thrombectomy (EVT):
  • Mechanical catheter clot retrieval within 6 hours of onset (or up to 24 hours in selected patients based on CT perfusion mismatch).
• Immediate Nursing Actions:
  • Strict NPO (Nil By Mouth): Withhold all oral food, fluids, and medications until a formal bedside swallow screening tool is completed by a trained nurse or speech and language therapist (prevent fatal aspiration pneumonia).
  • Emergency Non-Contrast CT Brain: Mandatory within 30 minutes to exclude intracranial haemorrhage before considering antiplatelet or thrombolytic therapy.
  • Capillary Blood Glucose: Check immediately to rule out neuroglycopenia (hypoglycaemia can mimic an acute stroke).
  • Blood Pressure Management: Maintain permissive hypertension unless BP exceeds >220/120 mmHg (or >185/110 mmHg if candidate for thrombolysis).

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4. Delirium vs. Dementia vs. Depression

Cognitive changes in acute inpatients are frequently misdiagnosed. The nurse must distinguish acute delirium from chronic dementia and depression:

Clinical Subtypes of Delirium

1. Hyperactive Delirium (25%): Agitation, restlessness, hallucinations, combativeness, wandering, pulling at lines/catheters. Readily recognized.
2. Hypoactive Delirium (50%): Quiet, somnolent, lethargic, withdrawn, reduced motor activity. Carries equal or worse mortality than hyperactive delirium because it is frequently missed or dismissed as "just tired" or dementia.
3. Mixed Delirium (25%): Fluctuates between hyperactive and hypoactive states.

Screening Tools: The 4AT and CAM

• The 4AT Tool: Recommended across Irish hospitals for inpatient delirium screening. Assesses 4 domains:
  1. Alertness (Normal = 0; Mild sleepiness = 0; Abnormal/hyperalert/hypoalert = 4)
  2. AMT4 (Age, Date of birth, Place, Current year: 0 errors = 0; 1 error = 1; 2+ errors = 2)
  3. Attention (Months of the year backwards: 7+ correct = 0; <7 correct or refuses = 1; Untestable = 2)
  4. Acute change or fluctuating course (No = 0; Yes = 4)
  • Score ≥ 4 suggests delirium.
• Confusion Assessment Method (CAM): Requires Feature 1 (Acute onset and fluctuating course) AND Feature 2 (Inattention), plus EITHER Feature 3 (Disorganized thinking) OR Feature 4 (Altered level of consciousness).

Systematic Investigation of Delirium: The PINCH ME Mnemonic

flowchart LR
    A["P: Pain"] --> Z["Systematic Investigation<br/>of Acute Delirium"]
    B["I: Infection UTI / Chest / Sepsis"] --> Z
    C["N: Nutrition / Malnutrition"] --> Z
    D["C: Constipation / Retention"] --> Z
    E["H: Hydration / Dehydration"] --> Z
    F["M: Medication / Polypharmacy / Sedatives"] --> Z
    G["E: Environment / Sensory Impairment"] --> Z

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5. Clinical Pitfalls in Neurological Nursing