Advanced Cardiac Life Support

The four are: (1) Ventricular Fibrillation (VF)—chaotic, disorganized activity; (2) Pulseless Ventricular Tachycardia (PVT)—fast, organized but no perfusion; (3) Asystole (flatline)—no electrical activity; (4) Pulseless Electrical Activity (PEA)—organized on monitor but no pulse. VF and PVT are shockable; defibrillate immediately and give epinephrine 1 mg IV/IO every 3–5 minutes, plus amiodarone 300 mg after the first shock (or 5–10 mg/kg if pediatric). Asystole and PEA are non-shockable; give epinephrine and continue CPR while searching for reversible causes (volume loss, hypoxia, pulmonary embolism, cardiac tamponade, tension pneumothorax, hypothermia, toxins, thrombosis—the H's and T's). High-quality CPR is the backbone; meds and shocks are adjuncts.

An EKG is a tracing of the heart's electrical activity. In ACLS, you learn to identify six core rhythms: sinus rhythm (regular, organized), atrial fibrillation (irregularly irregular, no clear P wave), ventricular tachycardia (wide, fast, regular), atrial flutter (sawtooth), bradycardia (slow sinus or nodal block), and the four arrest rhythms above. Key features: P wave (atrial contraction), QRS (ventricular contraction), T wave (repolarization), PR interval (AV conduction), and QT interval (ventricular action potential). For ACLS, focus on: Does the patient have a pulse? Is the rhythm shockable (VF, PVT) or non-shockable (asystole, PEA, organized rhythms)? Narrow QRS = supraventricular origin; wide QRS = ventricular origin. Bradycardia <60 bpm; tachycardia >100 bpm. Practice strips until you identify rhythms instantly.

Defibrillation is unsynchronized shock for a patient in VF or PVT without a pulse. Cardioversion is synchronized shock (the defibrillator waits for the R wave) for a patient with a pulse but a dangerous arrhythmia (atrial flutter, atrial fibrillation with rapid ventricular response, ventricular tachycardia). Defibrillate immediately for VF/PVT; cardiovert a stable patient with SVT or rapid AFib after IV access and sedation if possible. Starting energies: adult defibrillation 200 J (monophasic) or 150–200 J (biphasic); pediatric 2–4 J/kg. Always clear the patient before shocking (no one touching).

Epinephrine (adrenaline) 1 mg IV/IO every 3–5 minutes—increases coronary and cerebral perfusion pressure. Amiodarone 300 mg IV/IO for VF/PVT after the first shock, then 150 mg after 3–5 minutes if VF/PVT recurs. Atropine 0.5–1 mg IV for symptomatic bradycardia (hypotensive, altered). Sodium bicarbonate for tricyclic antidepressant overdose or severe metabolic acidosis. Calcium chloride or gluconate for hyperkalemia (peaked T waves on EKG). Naloxone (Narcan) for opioid overdose causing respiratory depression. All IV or intraosseous (IO, drilled into tibia or humerus if no IV). The goal is to restore perfusion, oxygenation, and remove the cause—medications are only part of the puzzle.

Code leadership rotates: the most senior provider (physician or RN) leads initially. Designate roles: CPR (compressions and ventilation), IV/IO access, medications, rhythm assessment, airway, documentation. Rotate compressors every 2 minutes (state 'change in 30 seconds' so the incoming compressor is ready). Communicate clearly and often: 'Compressions are hard and fast, IV in place, giving epi now, rhythm is VF, shock in 10 seconds—clear.' If a paramedic arrives, hand off to them if they are more experienced; if you remain the most senior, you stay in charge. Pause CPR only for rhythm check or to deliver a shock. Aim for minimal interruption: <10 seconds between compressions and shock. Hand off to advanced life support (ICU team, cardiac team) once the patient has return of spontaneous circulation (ROSC).

The H's and T's: Hypoxia (check oxygen, verify tube placement), Hypovolemia (fluid loss—give IV fluids, arrange transfusion), Hypothermia (slow rewarming for cold patients), Hyperkalemia or other metabolic (EKG, labs), Tension pneumothorax (asymmetric breath sounds, tracheal deviation—needle decompression), Tamponade (muffled heart sounds, JVD—ultrasound, pericardiocentesis), Thrombosis (pulmonary embolism—consider thrombolytics, cardiac—catheterization), Toxins (overdose—specific antidotes). Use point-of-care ultrasound (POCUS) to visualize the heart, look for cardiac motion, fluid around the heart, or lung sliding. Search for signs while continuing CPR. If you find a reversible cause, treat it: fluids for hypovolemia, needle decompression for tension, thrombolytics for PE or MI, rewarming for hypothermia.

After return of spontaneous circulation (ROSC), the goal is a perfusing rhythm and neurological recovery. Minimize hypoxia (titrate oxygen), maintain normothermia (prevent fever; consider induced hypothermia 32–36°C if the patient is comatose—improves brain outcomes), check a 12-lead EKG (STEMI means cardiac catheterization), get labs (lactate, blood sugar, potassium), place a central line if indicated, and prepare for ICU admission. In the ED or ICU, the team will pursue the cause (imaging for stroke, troponin for MI, toxin screen for overdose). Keep the patient sedated and paralyzed if intubated. Monitor for post-resuscitation shock (low blood pressure despite fluids—may need vasopressors). Neurological prognostication is delayed 72 hours or more (sedation, hypothermia, and meds confound the exam). Many patients survive with good neurological outcome if resuscitation is prompt and post-resuscitation care is meticulous.