PALS Bradycardia Algorithm: A Step-by-Step Breakdown

In pediatric Advanced Cardiovascular Life Support (PALS), few algorithms require as much critical thinking as the Bradycardia with a Pulse algorithm. While bradycardia can be a sign of a healthy, athletic heart in adults, in pediatrics, it is often a late, ominous sign of respiratory failure or shock.

As healthcare providers, we know that cardiac arrest in children is rarely a sudden primary event. It is usually the progression of unrecognized hypoxia and ischemia. The heart slows down because it is starved of oxygen or overwhelmed by pressure.

This guide is designed to be a comprehensive pillar piece for your study library. We will dissect the PALS Bradycardia Algorithm into manageable, actionable steps, ensuring you understand the why behind every intervention.

Quick Answer: When to Start the PALS Bradycardia Algorithm

Use the PALS bradycardia algorithm when a child has:

Heart rate <60 bpm
Signs of poor perfusion
No improvement after oxygenation and ventilation

What is Pediatric Bradycardia?

According to the American Heart Association (AHA), pediatric bradycardia is defined as a heart rate slower than the normal range for the child’s age. However, the clinical threshold for intervention is strict.

Signs of Cardiopulmonary Compromise (Poor Perfusion)

Hypotension: Low blood pressure for age.
Altered Mental Status: Lethargy, irritability, or unresponsiveness.
Signs of Shock: Pallor, cyanosis, or delayed capillary refill.

Why is a slow heart rate dangerous in kids?

Children rely heavily on heart rate to maintain cardiac output.

Cardiac Output = Heart Rate × Stroke Volume.

Because a child’s stroke volume is relatively fixed, if the heart rate drops, cardiac output drops, leading to hypotension and eventually cardiac arrest.

The PALS Bradycardia Algorithm: A Step-by-Step Breakdown

The algorithm is designed to identify the cause, support the patient, and prevent arrest. Here is the expert breakdown.

Step 1: Recognition and Assessment

The first step is always identifying that the patient is compromised. You are assessing for two things simultaneously: Rate and Perfusion.

Check Heart Rate: Is it < 60 bpm?
Assess Clinical Status: Does the patient show signs of poor perfusion?
- Hypotension
- Altered mental status (lethargy, unresponsiveness)
- Pallor or cyanosis
- Prolonged capillary refill

If the heart rate is < 60 bpm AND there are signs of poor perfusion, proceed to Step 2 immediately.

Note: If the child is bradycardic (e.g., HR 50) but is awake, alert, and pink with warm extremities, this may be an athletes’ heart or vagal response. Do not intervene aggressively. Support the ABCs and monitor.

Step 2: Initial Management (Support ABCs)

Once significant bradycardia is identified, your priority is oxygenation and ventilation.

Maintain Airway: Open the airway using head-tilt/chin-lift or jaw thrust (if trauma is suspected).
Provide Oxygen: Administer 100% oxygen using a non-rebreather mask or bag-mask device (BVM).
Assist Breathing: If the respirations are inadequate or the child is in respiratory distress, begin positive-pressure ventilation (PPV).
- Clinical Pearl: In pediatrics, hypoxia is the most common cause of bradycardia. Often, simply providing effective ventilation with oxygen will cause the heart rate to increase naturally without drugs.

Step 3: Identify the Cause (The H’s and T’s)

While supporting the patient, you must rapidly identify reversible causes. In pediatric bradycardia, the culprits are usually found within the H’s and T’s:

Hypoxia: (Most common)
Hypovolemia: Dehydration or hemorrhage.
Hypo/Hyperkalemia: Electrolyte imbalances.
Hypoglycemia: Low blood sugar (always check a glucose!).
Hypothermia: Cold exposure.
Toxins: Poisoning or overdose.
Trauma: Internal injury or head injury causing increased intracranial pressure.
Tamponade (Cardiac): Fluid around the heart.
Tension Pneumothorax: Collapsed lung.

Step 4: The Critical Decision Point – CPR or Drugs?

This is the step where providers often hesitate during testing and real life. You must evaluate the response to initial oxygenation and ventilation.

Scenario A: The Heart Rate Remains Low (<60) AND Perfusion is Poor

Action: Begin Chest Compressions (CPR) immediately.
Ratio: 30:2 for 1 rescuer; 15:2 for 2 rescuers (until an advanced airway is placed).
Why? The heart rate is too slow to pump blood to the brain. You must manually pump for the heart.

Scenario B: Hypotension is Present

Action: Even if the pulse is palpable, if the patient is hypotensive, begin CPR.

Step 5: Pharmacological Interventions

While CPR is ongoing (or if the bradycardia is severe but stable enough to delay CPR), administer medications.

Atropine Sulfate

Indication: First-line drug for increased vagal tone or primary AV block.
Dose: 0.02 mg/kg (Minimum dose: 0.1 mg; Maximum dose: 0.5 mg for child, 1 mg for adolescent).
Route: IV/IO push.
Note: Can be given endotracheally (ET), but IV/IO is preferred. Do not use Atropine for bradycardia caused by hypoxia or heart transplant (denervated heart). In those cases, go straight to Epinephrine.

Epinephrine

Indication: If Atropine is ineffective (or contraindicated), or if the bradycardia is due to hypoxia, shock, or asystole/PEA arrest.
Dose: 0.01 mg/kg (1:10,000 concentration).
Route: IV/IO push.
Follow up: Can repeat every 3 to 5 minutes.
Infusion: Consider a continuous Epinephrine infusion (dopamine or epinephrine drip) if the patient responds but drops back down.

Consider Transcutaneous Pacing (TCP)

If pharmacological therapy and CPR fail to improve the heart rate or blood pressure, begin TCP.
Note: Pacing is painful and may require sedation, but restoring perfusion is the priority.

Conclusion

The PALS Bradycardia Algorithm is not just a flowchart, it is a roadmap to preventing cardiac arrest. By identifying poor perfusion early, aggressively supporting the ABCs, and understanding when to initiate CPR and administer Atropine or Epinephrine, you can intervene effectively when seconds matter.

This algorithm emphasizes that in pediatrics, treat the cause, not just the rhythm. Usually, fixing the hypoxia or shock fixes the heart rate.

Learn how to apply this in real scenarios with our PALS certification course.

Frequently Asked Questions (FAQ)

What is the initial drug of choice for symptomatic pediatric bradycardia?

Epinephrine is generally the first-line drug for bradycardia resulting from hypoxia. Atropine is preferred for bradycardia caused by increased vagal tone or primary AV block.

When should you start CPR for a child with a slow heartbeat?

Start CPR immediately if the heart rate is less than 60 bpm and the child shows signs of poor perfusion (hypotension, altered mental status) despite receiving oxygen and ventilation.

Is vagal maneuver a treatment for pediatric bradycardia?

While vagal maneuvers are used to treat SVT (Supraventricular Tachycardia) in children, they are not a standard treatment for bradycardia. Vagal stimulation typically slows the heart rate further, which could be dangerous in a patient already presenting with bradycardia.

What is the maximum dose of Atropine in the PALS Bradycardia algorithm?

The maximum dose of Atropine sulfate for a child is 0.5 mg (via IV/IO). For an adolescent (approaching adult dosing), the maximum single dose is 1 mg. The minimum dose to avoid paradoxical bradycardia is 0.1 mg.

Why is hypoxia a common cause of bradycardia in children?

Infants and young children have a high oxygen demand relative to their oxygen stores. When the airway is obstructed or ventilation fails (hypoxia), oxygen levels in the blood drop rapidly. The heart muscle responds to the lack of oxygen by slowing down, which leads to decreased cardiac output and eventual cardiac arrest if not corrected.