16.2 Stroke & Neurologic Emergencies in the Lab

16.2 Stroke & Neurologic Emergencies in the Lab

Neurologic emergencies in the cardiac catheterization laboratory demand immediate recognition because reperfusion therapies for ischemic stroke are strictly time-limited. The RCIS is often the first team member to notice subtle changes in mentation, speech, or motor function during sedation, contrast administration, or sheath manipulation. Delayed recognition converts a potentially treatable event into permanent disability.

Acute Ischemic Stroke During Cath Procedures

Stroke complicates cardiac catheterization at a rate of approximately 0.1–0.3% for diagnostic procedures and may be higher during complex structural or prolonged interventional cases. Embolic stroke can arise from aortic atheroma dislodgement, thrombus from guide catheters, guide-wire manipulation, or post-procedural atrial fibrillation. Hemorrhagic stroke may occur in the setting of aggressive anticoagulation.

BE-FAST Bedside Screening

The RCIS should perform BE-FAST assessment whenever a patient develops sudden neurologic symptoms:

• B — Balance: Sudden loss of balance, coordination, or vertigo.
• E — Eyes: Sudden vision change — double vision, partial blindness, or visual field cut.
• F — Face: Ask the patient to smile; look for unilateral facial droop.
• A — Arm: Ask the patient to raise both arms; one arm drifts downward or cannot be lifted.
• S — Speech: Slurred speech, word-finding difficulty, or inability to speak.
• T — Time: Record the exact time symptoms were first noticed (last known well). This timestamp determines eligibility for IV thrombolysis (alteplase within 4.5 hours) and mechanical thrombectomy (typically within 24 hours for selected large-vessel occlusions per institutional criteria).

Immediate Procedural Response

When stroke is suspected during an active procedure:

1. Stop the Procedure: The operator halts contrast injection, wire manipulation, and device deployment immediately.
2. Maintain Airway: Ensure the airway is patent; suction secretions if the patient has reduced consciousness or vomiting.
3. Obtain Vital Signs and Glucose: Check fingerstick blood glucose — hypoglycemia mimics stroke and is rapidly reversible with IV dextrose.
4. Activate Stroke Team: Notify neurology and the hospital stroke code per protocol; request emergent non-contrast head CT to differentiate ischemic from hemorrhagic stroke before any antithrombotic escalation beyond current procedure anticoagulation.
5. Document: Record symptom onset time, current medications (heparin, bivalirudin, GP IIb/IIIa inhibitors), ACT, and procedural details for the neurology team.
6. Do Not Administer Thrombolytics in the Lab: IV alteplase (tPA) requires CT confirmation of ischemic stroke and specialized neurology authorization — the RCIS prepares transport, not independent thrombolytic administration.

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Cerebral Air Embolism

Cerebral air embolism is a rare but catastrophic complication unique to invasive cardiovascular procedures. Air enters the arterial circulation through flush syringes, disconnected stopcocks, negative-pressure states during sheath removal, or direct injection from pressurized contrast systems.

Recognition

• Sudden altered mental status, confusion, or loss of consciousness during or immediately after a procedure step involving injection or catheter flushing.
• Focal neurologic deficits (hemiparesis, aphasia) appearing within seconds of a suspicious event.
• Seizure activity may accompany significant air load.
• Cardiovascular signs: sudden hypotension, "mill wheel" murmur (if large volume), or arrhythmia.

Immediate Management

1. Notify the Operator Immediately: Stop all injections and identify the source of air entry.
2. Left Lateral Decubitus with Trendelenburg (Head Down): This position traps air in the right ventricular apex (preventing pulmonary outflow obstruction) and increases cerebral venous pressure to reduce further arterial air transit. For suspected cerebral air, head-down positioning helps redirect air away from the cerebral circulation when feasible.
3. 100% Supplemental Oxygen: Administer high-flow oxygen to maximize the nitrogen gradient, accelerating absorption of nitrogen bubbles from air emboli (the bubble is ~80% nitrogen).
4. Hyperbaric Oxygen Therapy (HBOT): Definitive treatment for significant cerebral air embolism when available — neurology and hyperbaric medicine consultation should be initiated early.
5. Hemodynamic Support: IV fluids and vasopressors for hypotension; prepare for CPR if cardiovascular collapse occurs.
6. Aspiration Attempt: If a large air lock is visible in the right atrium on fluoroscopy or echocardiography, the operator may attempt aspiration via a catheter — this is physician-directed, but the RCIS prepares equipment.

Prevention (RCIS Responsibilities)

• De-air all flush syringes and manifolds before connection to the patient circuit — tap and invert syringes, use continuous flush systems with air filters where available.
• Verify all stopcocks are closed appropriately and connections are tight before any pressurized injection.
• Never flush catheters without confirming the syringe is free of visible air bubbles.
• Monitor patients closely during sheath exchanges and long procedures when micro-bubbles may accumulate.

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Seizures and Other Neurologic Events

Intraprocedural Seizures

Seizures during cath lab procedures may result from cerebral ischemia/embolism, air embolism, contrast-induced neurotoxicity (rare), hypoglycemia, electrolyte derangement, or pre-existing epilepsy triggered by stress or medication interaction.

Management Protocol:

1. Protect the Patient: Lower the table if safe; pad the head; do not restrain extremities forcefully.
2. Airway Management: Turn the head to the side, suction the mouth, apply supplemental oxygen.
3. Benzodiazepine Administration: IV lorazepam 2–4 mg or midazolam 2–5 mg per institutional seizure protocol; repeat once if seizure persists after 5 minutes (status epilepticus pathway).
4. Identify Cause: Check glucose, review recent contrast volume, assess for new focal deficits suggesting stroke or air embolism.
5. Resume Procedure Decision: Only the physician determines whether the procedure can safely continue after stabilization — most neurologic emergencies terminate the case.

Transient Ischemic Attack (TIA) vs. Stroke

A TIA produces the same focal neurologic symptoms as stroke but resolves completely within 24 hours (most within minutes). In the cath lab, any TIA-like event during a procedure should be managed identically to stroke until imaging excludes hemorrhage and symptoms fully resolve with observation.

Posterior Circulation Warning Signs

Vertebrobasilar ischemia may present atypically with:

• Sudden vertigo or dizziness (not explained by vasovagal response)
• Diplopia or dysarthria without limb weakness
• Ataxia or inability to sit upright
• Crossed findings (ipsilateral face weakness with contralateral body weakness)

These symptoms are easily attributed to sedation or contrast reaction — the RCIS must maintain a high index of suspicion and perform BE-FAST including balance and eye components.

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Coordination with the Stroke Team

After initial stabilization, the RCIS facilitates rapid transfer for non-contrast head CT (completed within 25 minutes of stroke code activation at comprehensive stroke centers). If ischemic stroke is confirmed and the patient is within the therapeutic window, neurology may administer IV alteplase or arrange emergent endovascular thrombectomy for large-vessel occlusion.

Anticoagulation status complicates post-cath stroke management. The neurology and cardiology teams jointly weigh hemorrhagic risk from recent heparin, bivalirudin, or GP IIb/IIIa inhibitors against the benefit of reperfusion. The RCIS provides precise documentation of all anticoagulant doses, ACT values, and procedure timing to support this decision.

Neurologic emergencies in the cath lab are unforgiving of delay. The RCIS role is early detection, immediate procedural cessation, precise time documentation, and seamless activation of the hospital stroke response — actions that directly determine whether the patient qualifies for life-restoring reperfusion therapy.