The six PALS algorithms are the backbone of the entire certification. Every scenario you work through in the course — and a large portion of the written exam questions — traces back to one of these algorithms. This guide walks through each one, explains the critical decision points, and highlights the parts that most test-takers miss.
Why the Algorithms Matter So Much
The AHA PALS algorithms aren't just study material — they're the structured decision frameworks that real resuscitation teams use during actual pediatric emergencies. The PALS course teaches you to apply them in real time under pressure. The written exam tests whether you know them precisely enough to make the right call at each decision branch.
A common mistake is to "understand" an algorithm without truly memorizing it. On the exam, questions are written to exploit the gaps between "generally familiar" and "actually knows it." The goal of this guide is to get you to the latter.
Algorithm 1: Systematic Approach / Pediatric Assessment Triangle
Before any algorithm kicks in, PALS requires a structured initial assessment. The Pediatric Assessment Triangle (PAT) is your 30-second visual impression before you even touch the patient. It has three components:
- Appearance — Tone, interactiveness, consolability, look/gaze, speech/cry
- Work of Breathing — Abnormal sounds, abnormal positioning, retractions, nasal flaring
- Circulation to Skin — Pallor, mottling, cyanosis
After the PAT, you proceed to the primary assessment using the ABCDE framework: Airway, Breathing, Circulation, Disability (neuro), Exposure. This is where you collect vital signs, perform hands-on assessment, and identify whether the child is in respiratory distress, respiratory failure, shock, or cardiac arrest.
What the exam tests here
Questions in this area often give you clinical findings and ask you to classify the problem (respiratory distress vs. failure vs. shock) or identify the appropriate next step. Know the difference between respiratory distress (compensated, increased work of breathing) and respiratory failure (decompensated, inadequate gas exchange).
Algorithm 2: Pediatric Cardiac Arrest Algorithm
This is the most heavily tested algorithm. It applies to all pulseless patients and branches based on whether the rhythm is shockable (VF, pulseless VT) or non-shockable (PEA, asystole).
Shockable Rhythms (VF / Pulseless VT)
- Defibrillate at 2 J/kg → resume CPR immediately
- After 2 minutes CPR: check rhythm, recheck pulse
- If shockable: defibrillate at 4 J/kg → resume CPR
- Give epinephrine 0.01 mg/kg IV/IO every 3–5 min
- If still shockable after 3rd shock: amiodarone 5 mg/kg IV/IO
- Continue 2-minute CPR cycles with rhythm checks between each
Non-Shockable Rhythms (PEA / Asystole)
- Begin CPR immediately — no shock
- Establish IV/IO access
- Epinephrine 0.01 mg/kg IV/IO as soon as access established, every 3–5 min
- Identify and treat reversible causes (H's and T's)
- Check rhythm every 2 minutes — if shockable rhythm develops, switch to shockable pathway
The H's and T's — know them cold
Reversible causes are frequently tested. Hypoxia, Hypovolemia, Hydrogen ion (acidosis), Hypo/hyperkalemia, Hypothermia — Tension pneumothorax, Tamponade, Toxins, Thrombosis (pulmonary and coronary). The exam will describe a clinical scenario and ask you to identify the most likely reversible cause.
Algorithm 3: Pediatric Bradycardia With a Pulse Algorithm
Bradycardia in a child is not always an emergency — it's only treated aggressively when it's causing cardiopulmonary compromise (poor perfusion, hypotension, altered mental status, respiratory distress).
The algorithm follows this logic:
- Identify bradycardia with pulse
- Is there cardiopulmonary compromise? If no — observe and monitor
- If yes — support ABCs, give supplemental oxygen
- Is bradycardia persisting despite oxygenation? If no — continue monitoring
- If yes — start CPR if HR < 60 with poor perfusion
- Epinephrine IV/IO or atropine IV/IO for vagal/AV block causes
- Consider transvenous pacing if medications are ineffective
Key exam point
The threshold for starting CPR in bradycardia is HR < 60/min with signs of poor perfusion — even with a pulse present. This surprises many test-takers. In pediatrics, a very slow rate with poor perfusion is treated as a pre-arrest condition requiring CPR.
Algorithm 4: Pediatric Tachycardia With a Pulse Algorithm
Tachycardia management hinges on two questions: Is the patient stable or unstable? And is the QRS narrow (<0.09 sec) or wide (≥0.09 sec)?
| QRS Width | Stability | First Intervention |
|---|---|---|
| Narrow (SVT likely) | Stable | Vagal maneuvers → Adenosine 0.1 mg/kg IV rapid push |
| Narrow (SVT likely) | Unstable | Synchronized cardioversion 0.5–1 J/kg (sedate if possible) |
| Wide (VT likely) | Stable | Expert consultation + amiodarone or procainamide IV (not both) |
| Wide (VT likely) | Unstable | Synchronized cardioversion 0.5–1 J/kg |
Note that adenosine is not used for wide-complex tachycardia. If a question presents a wide-complex rhythm and lists adenosine as an option, it's a distractor.
Algorithm 5: Post-Cardiac Arrest Care Algorithm
After achieving ROSC (Return of Spontaneous Circulation), the work isn't over. The post-arrest period is critical — hemodynamic instability and secondary brain injury are major risks. The PALS post-arrest algorithm focuses on targeted temperature management, oxygenation, and avoiding secondary insults.
- Oxygenation: Titrate SpO₂ to 94–99%. Avoid hyperoxia (can worsen neurologic outcome).
- Ventilation: Target PaCO₂ 35–45 mmHg. Avoid hyperventilation.
- Hemodynamics: Maintain MAP and systolic BP at or above the 5th percentile for age.
- Temperature: Prevent fever (≥38°C). Targeted temperature management if indicated.
- Glucose: Treat hypoglycemia and hyperglycemia. Avoid extremes.
- 12-lead ECG: Obtain to identify potentially treatable causes of arrest.
Exam focus
The most common post-arrest exam questions involve oxygenation targets. The answer is NOT 100% SpO₂ — it's 94–99%. Hyperoxia post-arrest is associated with worse neurologic outcomes, and the AHA specifically recommends against targeting 100% saturation.
Algorithm 6: Shock Recognition and Management
The shock algorithm isn't a single linear flowchart — it's a framework for classifying shock type and directing treatment. There are four types you must know:
Hypovolemic Shock
Most common type in pediatrics. Caused by fluid or blood loss. Warm early (compensated), cool late (decompensated). Treatment: isotonic fluid bolus 20 mL/kg, repeat as needed.
Distributive Shock
Includes septic shock and anaphylaxis. Maldistribution of blood flow due to vasodilation. Often presents as warm shock initially (warm extremities, bounding pulses). Treatment: aggressive fluid resuscitation, then vasoactive agents if fluid-refractory.
Cardiogenic Shock
Pump failure — heart can't generate adequate cardiac output. Classic signs: cool extremities, poor perfusion, possible hepatomegaly, jugular venous distension. Fluid boluses must be used cautiously. Vasoactive support is primary treatment.
Obstructive Shock
Mechanical obstruction of blood flow — tension pneumothorax, cardiac tamponade, massive PE. Treatment is directed at relieving the obstruction (e.g., needle decompression for tension pneumo), not just fluids.
The Best Way to Memorize All Six Algorithms
Reading through algorithms is not the same as knowing them. The most effective approach is the blank-sheet method: close your notes and try to draw out each algorithm from memory. Where you get stuck is exactly what you need to review. Repeat this process for all six algorithms at least three times each before your exam day.
After you can draw each algorithm from memory, use practice questions to test your ability to apply them in scenario format. That's the combination that builds the kind of knowledge the exam requires.