7.3 Integrated High-Yield Review and Exam Strategy
Key Takeaways
Adult high-quality CPR: rate 100–120/min, depth 2–2.4 in (5–6 cm), full recoil, 30:2 (no advanced airway) or continuous compressions with 1 breath every 6 sec (advanced airway), CCF ≥ 60% (target 80%), switch compressors every 2 min.
Cardiac arrest drugs: epinephrine 1 mg IV/IO every 3–5 min (all arrests); amiodarone 300 mg then 150 mg, or lidocaine 1–1.5 then 0.5–0.75 mg/kg (refractory VF/pVT only).
Bradycardia: atropine 1 mg IV every 3–5 min, max 3 mg; then transcutaneous pacing, dopamine 5–20 mcg/kg/min, or epinephrine 2–10 mcg/min.
Tachycardia: stable narrow regular → vagal then adenosine 6 mg then 12 mg; unstable → synchronized cardioversion.
Use the five H's and five T's in the AHA adult cardiac-arrest algorithm to organize the search for reversible causes of PEA/asystole and refractory arrest.
High-Quality CPR — the Numbers You Must Know Cold
Most BLS/ACLS items hinge on a handful of exact figures. Memorize this table; these are the most frequently tested numbers on the entire exam (2025 AHA Guidelines).
| Parameter | Adult | Child (1 yr–puberty) | Infant (< 1 yr) |
|---|---|---|---|
| Rate | 100–120/min | 100–120/min | 100–120/min |
| Depth | ≥ 2 in (5 cm), not > 2.4 in (6 cm) | ~2 in (5 cm), ~⅓ AP chest depth | ~1.5 in (4 cm), ~⅓ AP chest depth |
| Ratio (1 rescuer) | 30:2 | 30:2 | 30:2 |
| Ratio (2 rescuers) | 30:2 | 15:2 | 15:2 |
| Hand/finger position | 2 hands, lower half of sternum | 1–2 hands, lower half of sternum | Heel of 1 hand or 2-thumb encircling |
| With advanced airway | Continuous compressions + 1 breath every 6 sec (10/min) | 1 breath every 2–3 sec (20–30/min) | 1 breath every 2–3 sec (20–30/min) |
Universal rules: allow full chest recoil, minimize interruptions (chest-compression fraction at least 60%, target 80%), switch compressors every 2 minutes to prevent fatigue-related quality loss, and avoid excessive ventilation. For a witnessed adult collapse with a shockable rhythm, time to first defibrillation is the strongest survival driver — every minute of delay drops survival roughly 7–10%.
Defibrillation / cardioversion energy
- Defibrillation (VF/pVT): biphasic, use the manufacturer's recommended dose (commonly 120–200 J); if unknown, use the maximum. Monophasic = 360 J.
- Synchronized cardioversion (unstable tachycardia): the 2025 ACLS initial energy settings are 100 J for narrow-complex tachycardia, 100 J for monomorphic VT, and 200 J for atrial fibrillation or atrial flutter. Escalate if unsuccessful as appropriate for the device and rhythm. Polymorphic VT requires an unsynchronized high-energy shock.
ACLS Drug Doses — Arrest, Brady, Tachy
These are the highest-yield pharmacology facts. Learn the dose, route, interval, and maximum for each.
Cardiac arrest
| Drug | Dose | Notes |
|---|---|---|
| Epinephrine | 1 mg IV/IO every 3–5 min | Given in every arrest. In PEA/asystole give ASAP; in VF/pVT give after the second shock. |
| Amiodarone | 300 mg IV/IO, then 150 mg | Refractory VF/pVT only (after CPR, defibrillation, epinephrine). |
| Lidocaine | 1–1.5 mg/kg, then 0.5–0.75 mg/kg | Alternative to amiodarone for refractory VF/pVT. |
Symptomatic bradycardia
| Step | Therapy |
|---|---|
| First-line drug | Atropine 1 mg IV every 3–5 min, maximum total 3 mg. |
| If atropine ineffective | Transcutaneous pacing, OR dopamine 5–20 mcg/kg/min, OR epinephrine 2–10 mcg/min infusion. |
Note the 2023 update raised the initial atropine dose to 1 mg (from the older 0.5 mg). Atropine is generally ineffective for high-degree (Mobitz II / third-degree) AV block — go to pacing.
Tachycardia (with a pulse)
| Patient state | Action |
|---|---|
| Unstable (hypotension, altered mental status, signs of shock, ischemic chest discomfort, acute heart failure) | Synchronized cardioversion now. |
| Stable, narrow regular (SVT) | Vagal maneuvers → adenosine 6 mg rapid IV push, then 12 mg if needed → AV-nodal blocker (beta-blocker or calcium-channel blocker). |
| Stable, narrow irregular (e.g., A-fib) | Rate control (beta-blocker or diltiazem). |
| Stable, wide regular | Adenosine may be considered (if regular and monomorphic) or an antiarrhythmic infusion (procainamide, amiodarone, sotalol). |
Key trap: adenosine must be given as a rapid IV push followed by a saline flush, and it is used only for regular rhythms.
The H's and T's, and the Priority-Question Strategy
The 2025 AHA adult cardiac-arrest algorithm lists five H's and five T's to guide the search for reversible causes, especially in PEA and asystole:
| H's | T's |
|---|---|
| Hypovolemia | Tension pneumothorax |
| Hypoxia | Tamponade (cardiac) |
| Hydrogen ion (acidosis) | Toxins |
| Hypo-/Hyperkalemia | Thrombosis — pulmonary (PE) |
| Hypothermia | Thrombosis — coronary (MI) |
Classic links tested: hyperkalemia → peaked T waves + give calcium/bicarb/insulin-glucose; tension pneumothorax → needle decompression; tamponade → pericardiocentesis; hypovolemia → fluids; hypoxia → oxygenate/secure airway; coronary thrombosis → reperfusion; PE → consider thrombolytics.
Written-exam strategy: identify the state, choose the next action
The written test is overwhelmingly priority questions — "what do you do next?" Use this read order on every stem:
- Age — adult, child, or infant (changes depth and 2-rescuer ratio).
- Pulse — pulseless drives the arrest algorithm; a pulse drives brady/tachy/ACS/respiratory pathways.
- Breathing — apneic vs. respiratory distress.
- Rhythm — shockable (VF/pVT) vs. nonshockable (PEA/asystole) vs. brady vs. tachy.
- Stability — stable vs. unstable (unstable tachy → cardioversion; unstable brady → atropine/pacing).
- Number of rescuers — single vs. two (pediatric ratio).
Then eliminate distractors: cross out answers that interrupt CPR, shock a nonshockable rhythm, treat a stable patient as unstable, or do an advanced step that delays the immediate lifesaving action. If two answers are both true, pick the one that is most immediate and lifesaving (early CPR and defibrillation beat a later-correct drug). Manage time: answer every item (no penalty for guessing), flag hard ones, and don't overthink a simple BLS sequence.
What is the correct compression-to-ventilation ratio for a 6-year-old child in cardiac arrest when TWO trained rescuers are present and no advanced airway is in place?
30:2
5:1
Continuous compressions with no ventilations
15:2
A patient has symptomatic bradycardia unresponsive to atropine. The team has given atropine to the maximum total dose. What was that maximum, and what is the next step?
Maximum 1 mg total; next give amiodarone 300 mg.
Maximum 3 mg total; next start transcutaneous pacing or a dopamine (5–20 mcg/kg/min) or epinephrine (2–10 mcg/min) infusion.
Maximum 6 mg total; next deliver synchronized cardioversion.
Maximum 0.5 mg total; next give a fluid bolus and observe.
Which set lists ONLY reversible causes of cardiac arrest from the AHA H's and T's?
Hypertension, Tachycardia, Tinnitus, Hyperglycemia
Hyperthermia, Thrombocytopenia, Hypercalcemia, Trauma
Hypotension, Toxoplasmosis, Hyponatremia, Thyroid storm
Hypovolemia, Hypoxia, Tension pneumothorax, Tamponade
A stable patient has a regular narrow-complex tachycardia at 180/min unresponsive to vagal maneuvers. What is the next pharmacologic step?
Adenosine 6 mg rapid IV push, followed by 12 mg if it persists.
Synchronized cardioversion at 200 J.
Atropine 1 mg IV push.
Amiodarone 300 mg IV bolus.
Sections you finish are checked off in the contents.