ACLS, Codes, and Peri-Arrest Cardiology

Codes are where preparation shows. You may be a code-team member or, depending on your setting, run one. The fundamentals are the same everywhere: recognize arrest fast, deliver high-quality CPR, defibrillate shockable rhythms early, give epinephrine, and hunt the reversible cause — while keeping interruptions to a minimum.

1. 1.Unresponsive + no normal breathing + no definite pulse within 10 seconds → call for help/activate the code and start CPR.
2. 2.Push hard and fast: rate 100–120/min, depth ≥2 inches (≈5 cm, not more than 6 cm), full chest recoil, minimal interruptions.
3. 3.Apply the defibrillator/monitor as soon as it arrives and aim for a high compression fraction (compressions most of the time).
4. 4.Get airway/ventilation and IV/IO access without stopping good compressions.

• •Shockable — ventricular fibrillation (VF) or pulseless ventricular tachycardia (pVT): defibrillate immediately, then resume CPR at once for ~2 minutes before the next rhythm check.
• •Non-shockable — pulseless electrical activity (PEA) or asystole: do NOT shock; high-quality CPR and hunt the cause.
• •Reassess rhythm/pulse during the brief pulse check every ~2 minutes; minimize the pause.
• •Epinephrine timing differs by arm: in VF/pVT give the first epinephrine AFTER the second shock (shock + CPR come first); in PEA/asystole give epinephrine as soon as you have access. Both then repeat every 3–5 min.

• •Energy: biphasic 120–200 J for the first shock (use your device’s recommended setting); escalate to a higher/maximal energy on subsequent shocks. Monophasic = 360 J.
• •Charge while compressions continue, clear briefly, shock, and resume CPR immediately — keep the peri-shock pause to a few seconds.
• •Don’t stack shocks or pause to recheck a pulse right after a shock — the post-shock heart usually needs CPR before any rhythm organizes.

• •Epinephrine 1 mg IV/IO every 3–5 min — the one drug given in every arrest. High-dose epinephrine is NOT recommended.
• •Antiarrhythmic for shock-refractory VF/pVT: amiodarone 300 mg IV/IO first dose, then 150 mg; OR lidocaine 1–1.5 mg/kg first, then 0.5–0.75 mg/kg.
• •Magnesium 1–2 g IV is for torsades / polymorphic VT with a long QT — not a routine arrest drug.
• •Reach for the cause-specific drugs too (e.g., calcium for hyperkalemia) — see the reversible causes below.

• •Continuous waveform capnography confirms (and keeps confirming) endotracheal tube placement and gives live feedback on CPR quality.
• •A persistently low ETCO₂ (<10 mmHg) despite CPR suggests inadequate compressions or a low likelihood of ROSC — push harder/faster and reassess.
• •An abrupt, sustained rise (often to >35–40 mmHg, or a jump of ≥10) is a strong sign of ROSC — confirm at the next pulse/rhythm check.

• •Hypovolemia → IV fluids/blood and control bleeding. Hypoxia → oxygenate and confirm ventilation / tube placement.
• •Hydrogen ion (acidosis) → ventilation; consider bicarbonate in specific settings (known severe acidosis, hyperkalemia, sodium-channel-blocker toxicity).
• •Hyperkalemia → calcium (chloride or gluconate) FIRST to stabilize the myocardium, then insulin + dextrose, bicarbonate, ± albuterol. Hypokalemia / hypomagnesemia → replace K and Mg.
• •Hypothermia → active rewarming and prolonged efforts (“not dead until warm and dead”).
• •Tension pneumothorax → immediate needle/finger thoracostomy. Tamponade → pericardiocentesis (point-of-care echo identifies both).
• •Toxins → targeted antidotes (naloxone; lipid emulsion for local-anesthetic toxicity; glucagon / high-dose insulin for β-blocker / calcium-channel-blocker). Thrombosis — PE → consider thrombolysis / ECPR (extracorporeal cardiopulmonary resuscitation, i.e. CPR supported by ECMO); coronary (MI) → emergent PCI after ROSC.
• •In cardiology arrests, coronary thrombosis (MI), hyperkalemia, tamponade, and PE are especially worth chasing.

• •Unstable tachycardia (hypotension, ischemia, shock, altered mentation, pulmonary edema) → synchronized cardioversion. Energy is device-specific; traditional starting energies are ~50–100 J for a regular narrow complex (SVT), ~120–200 J for atrial fibrillation, and ~100 J for monomorphic VT with a pulse.
• •Stable, regular narrow-complex tachycardia → vagal maneuvers, then adenosine 6 mg rapid IV push, then 12 mg if needed (also diagnostic).
• •Unstable bradycardia → atropine 1 mg IV every 3–5 min (max 3 mg); if it fails, transcutaneous pacing and/or a chronotropic infusion (dopamine 5–20 mcg/kg/min or epinephrine 2–10 mcg/min).
• •“Unstable” means act now — don’t titrate oral agents in a crashing patient.

• •Pregnancy (≈≥20 weeks): continuous manual LEFT uterine displacement during CPR; if no ROSC, the team performs perimortem cesarean delivery — aimed for around 4–5 minutes of arrest — to aid maternal resuscitation.
• •Opioid overdose: give naloxone for a suspected opioid emergency with a pulse; in true cardiac arrest, run standard ACLS and don’t delay CPR/defibrillation for naloxone.
• •Local-anesthetic systemic toxicity (LAST): IV lipid emulsion 20% alongside ACLS.

• •Oxygenation/ventilation: avoid hypoxia AND hyperoxia — titrate SpO₂ to 92–98% — and target normocapnia (PaCO₂ ~35–45); avoid over-ventilating.
• •Hemodynamics: avoid hypotension and support an adequate MAP (commonly ≥65 mmHg, individualized).
• •Get a 12-lead and pursue emergent coronary angiography for STEMI / suspected ischemic arrest.
• •Targeted temperature management / actively avoid fever in comatose survivors; treat the precipitant; transfer to ICU.
• •Do NOT neuro-prognosticate early — wait until confounders clear (generally ≥72 h) before drawing conclusions about recovery.

• •Interrupting compressions too long (for pulse checks, intubation, line placement).
• •Shocking asystole/PEA (non-shockable) or delaying epinephrine in them.
• •Forgetting the H’s and T’s — running the algorithm but never treating the cause.
• •Not getting a post-ROSC 12-lead / missing the STEMI that caused the arrest.
• •Not knowing the code-drug doses/sequence well enough to catch an error on the team.
• •Hyperventilating the patient (during or after the arrest).

• •Nurses often start CPR, push code meds, and document the timeline; you help run the algorithm, call the rhythm decisions, and coordinate post-ROSC care and disposition.