Cardiovascular Emergencies

Cardiac Arrest

Cardiac arrest is the sudden loss of effective cardiac output. The heart stops pumping blood to the brain and body. Without immediate CPR and defibrillation when appropriate, death occurs within minutes.

The Four Cardiac Arrest Rhythms

• Ventricular Fibrillation (VF) — Chaotic, disorganized electrical activity. The heart quivers instead of pumping. Shockable.
• Pulseless Ventricular Tachycardia (pVT) — Fast, organized rhythm but no mechanical output. Shockable.
• Pulseless Electrical Activity (PEA) — Organized electrical activity, no pulse. Treat the cause (H's and T's). Not shockable.
• Asystole — Flatline. No electrical or mechanical activity. Not shockable.

High-Quality CPR — The Non-Negotiables

• Rate: 100–120 compressions per minute
• Depth: At least 2 inches (but no more than 2.4 inches) for adults
• Full recoil: Let the chest fully recoil between compressions — don't lean on the chest
• Minimize interruptions: Pause <10 seconds for rhythm checks and shocks
• Ratio: 30 compressions : 2 breaths (1-rescuer); once advanced airway placed → continuous compressions + 1 breath every 6 seconds
• Switch compressors every 2 minutes to prevent fatigue — quality drops fast

AED Use

• Apply pads as soon as available — don't wait. Upper right chest, lower left lateral chest (or apex)
• Continue CPR while AED is charging
• Clear the patient before analyzing and shocking — "Everyone clear!"
• Immediately resume CPR after shock — don't check pulse first
• Analyze rhythm every 2 minutes

Shock

Shock is inadequate perfusion of tissues — cells aren't getting the oxygen they need. It's not just low blood pressure. The three main types you'll encounter:

• Hypovolemic shock — Not enough blood volume (hemorrhage, severe dehydration). Signs: tachycardia, pale/cool/clammy, hypotension (late sign). Treat: control bleeding, position (supine or legs elevated if not contraindicated), keep warm, rapid transport.
• Cardiogenic shock — The heart can't pump effectively (severe MI, heart failure). Signs: same as hypovolemic but may have JVD and crackles in lungs. Transport to ALS.
• Distributive shock — Blood vessels dilate excessively (anaphylaxis = warm, flushed; neurogenic = bradycardia; septic = fever). Each has different treatment — covered in Module 6.

Chest Pain — Suspected Cardiac

Classic MI presentation: crushing, pressure-like chest pain radiating to the left arm, jaw, or shoulder. Associated with diaphoresis, nausea, and shortness of breath. Women and diabetics may present atypically — fatigue, nausea, jaw pain, or back pain without classic chest pain.

Your BLS treatment for suspected MI:

• Position of comfort — usually sitting up (30–45°)
• Oxygen — if SpO₂ <94%
• Aspirin 324 mg (4 × 81 mg) — chewed, not swallowed whole — if no allergy and no active GI bleeding
• Nitroglycerin — if patient has their own prescribed nitro and BP ≥100 mmHg systolic
• ALS intercept — call for a medic unit
• 12-lead ECG if available — don't delay transport for it

Nitroglycerin — Key Rules

• Dose: 0.4 mg SL (under the tongue), may repeat every 5 min × 3 doses if BP remains ≥100
• Contraindications: SBP <100 mmHg, use of erectile dysfunction medications in past 24–48 hours (sildenafil/Viagra, tadalafil/Cialis), right ventricular MI
• Causes vasodilation — can drop BP significantly. Reassess BP after each dose.
• EMTs assist with patient's own prescribed nitro — you do not carry it independently in most BLS systems

Epinephrine Auto-Injector (Anaphylaxis)

• Dose: 0.3 mg IM, anterolateral thigh (adults). 0.15 mg for children <66 lbs.
• Indicated for anaphylaxis — life-threatening allergic reaction with systemic signs (hypotension, stridor, bronchospasm, hives + respiratory/cardiovascular compromise)
• Can repeat in 5–15 min if no improvement and additional auto-injector available
• Transport immediately after — epinephrine wears off in 15–20 min and reaction can return