3.1 Pediatric BLS Overview and Why It Differs

Defining Child vs Infant

Pediatric BLS rests on two age definitions that the exam tests directly. An infant is younger than 1 year of age (excluding the newly born in the delivery room, who fall under neonatal resuscitation). A child runs from 1 year of age until the onset of puberty — signs of puberty are breast development in females and axillary (underarm) hair in males. Once a victim shows signs of puberty, treat them with adult BLS: adult depth, adult AED energy, and the adult choking sequence.

Get the age band right first, because nearly every downstream choice — compression depth, hand technique, pulse-check site, and AED equipment — branches from it.

This age model comes from the American Heart Association (AHA) Pediatric Basic Life Support guidelines (2020, carried forward in the 2025 focused update). When a question states an age, anchor on it before reading the answer options.

Why Pediatric Arrest Is Different

The single most important conceptual difference is cause. Adult sudden cardiac arrest is usually a primary cardiac event — most often ventricular fibrillation (VF) from coronary disease — so defibrillation is the time-critical intervention. In children and infants, arrest is most commonly asphyxial: it follows progressive respiratory failure or shock that culminates in hypoxia, bradycardia, and finally a pulseless arrest. By the time a child is pulseless, prolonged hypoxia has usually already occurred.

Two consequences follow. First, ventilation carries greater relative weight in pediatric resuscitation than in adult resuscitation, which is why two-rescuer pediatric CPR delivers ventilations twice as often (15:2 vs 30:2). Second, early recognition and treatment of respiratory distress prevents arrest — the best pediatric outcome is the arrest that never happens. A child who is bradycardic (heart rate under 60/min) with signs of poor perfusion despite adequate oxygenation and ventilation should receive chest compressions, because that bradycardia reflects critical hypoxia.

The Pediatric vs Adult Parameter Table

This comparison table is the high-yield core of the entire chapter. Verify every value against your course card, but these reflect current AHA guidance.

Note the traps embedded here: the rate is identical across all ages (100–120/min), so a question that varies rate by age is testing whether you know it does not change. What changes is depth, technique, the two-rescuer ratio, and the rescue-breathing rate.

How These Items Are Tested

BLS items test priority and discrimination. Read the patient state in order: age, pulse, breathing, number of rescuers, and equipment available. Then pick the action that protects oxygenation, perfusion, or defibrillation timing. An option that sounds advanced but delays compressions, ventilation, or a needed shock is usually the distractor.

A classic stem: an infant with bronchiolitis becomes limp, gray, and bradycardic at 40/min despite good bag-mask ventilation. The exam wants compressions plus ventilation — treat the hypoxic bradycardia as functional arrest — not an adult-style search for a shockable rhythm. Study by mixing pediatric items with adult and respiratory-arrest items so you can feel exactly where each rule applies.

The Pediatric Chain of Survival and Assessment Sequence

The pediatric in-hospital and out-of-hospital Chains of Survival differ from the adult chains by adding a strong prevention link at the front, precisely because most pediatric arrest is the predictable end of untreated respiratory or circulatory failure. The out-of-hospital pediatric chain runs: prevention of arrest, early high-quality CPR, rapid activation of emergency response, advanced resuscitation, post-arrest care, and recovery.

The practical lesson for a BLS provider is that recognizing a sick child early — increased work of breathing, grunting, nasal flaring, retractions, altered mental status, mottled or gray skin, weak pulses — and intervening with oxygen and ventilation is itself lifesaving.

The BLS assessment sequence for a collapsed child or infant is concrete and tested:

1. Ensure scene safety and check for responsiveness (tap and shout; for an infant, tap the foot).
2. Shout for help / activate the emergency response system; for a witnessed sudden collapse, get the AED immediately. For an unwitnessed collapse by a lone rescuer, give about 2 minutes of CPR first, then leave to activate and retrieve the AED.
3. Check breathing and pulse simultaneously for no more than 10 seconds — carotid or femoral in a child, brachial in an infant.
4. Decide the branch: normal breathing and pulse — monitor; pulse present but inadequate breathing — rescue breathing at 1 every 2–3 seconds; pulse under 60/min with poor perfusion, or no pulse — start CPR.

Why the 60/min Threshold Matters

The heart-rate-under-60-with-poor-perfusion rule is unique to pediatrics and a frequent exam point. In a hypoxic child, the heart slows before it stops; treating that bradycardia as functional arrest and starting compressions can prevent progression to a non-perfusing rhythm. There is no adult equivalent — adults in bradycardia with a pulse are managed on the ACLS bradycardia algorithm, not with compressions. Keeping these two worlds separate is exactly the discrimination the exam rewards.