4.1 Pediatric BLS Age Definitions & Initial Response
Key Takeaways
For BLS, an infant is younger than about 1 year, excluding a newly born infant; a child is about age 1 until signs of puberty; after puberty, use adult BLS.
Healthcare providers check a child carotid or femoral pulse and an infant brachial or femoral pulse while assessing breathing for no more than 10 seconds.
Pediatric cardiac arrest often follows respiratory failure or shock, so effective breaths are an essential part of CPR.
A lone rescuer who witnesses a sudden pediatric collapse prioritizes activation and AED retrieval; after an unwitnessed collapse without a phone, provide about 2 minutes of CPR before leaving.
Use 30:2 for one-rescuer infant or child CPR and 15:2 when 2 or more healthcare rescuers are present.
4.1 Pediatric BLS Age Definitions & Initial Response
Pediatric BLS adjusts technique to the patient's developmental size and to the common progression from respiratory compromise to cardiac arrest. The course uses practical age categories so rescuers can choose the correct pulse site, compression depth, hand method, ratio, and AED equipment.
BLS age categories
| Category | BLS definition |
|---|---|
| Infant | Younger than about 1 year, excluding the newly born infant |
| Child | About age 1 until signs of puberty |
| Adult | Puberty and older |
Signs of puberty include chest or underarm hair in males and breast development in females. When age is uncertain, assess body size and developmental signs and use the category that best fits the patient and available equipment. Do not delay care while trying to identify an exact birthday.
Newly born infants at the time of birth are treated under neonatal resuscitation guidance, not the BLS infant algorithm.
Initial pediatric assessment
After confirming scene safety, check responsiveness: tap a child's shoulders or tap an infant's foot and shout. Call for nearby help. Assess breathing and a central pulse simultaneously for no more than 10 seconds:
- Child: carotid or femoral pulse.
- Infant: brachial or femoral pulse.
If no definite pulse is felt, begin CPR. If a pulse is present but breathing is absent or inadequate, give 1 breath every 2-3 seconds and reassess about every 2 minutes.
For an infant or child, a pulse below 60/min with signs of poor perfusion despite effective oxygenation and ventilation is also an indication to begin compressions. This prevents prolonged treatment of severe bradycardia as though it were adequate circulation.
Activation when one rescuer is present
If a mobile phone is available, activate emergency response on speaker and begin care without leaving the patient. If the lone rescuer has no phone and must leave:
- Witnessed sudden collapse: activate emergency response and obtain an AED first, then return and begin CPR. A sudden witnessed collapse is more likely to have a shockable cardiac cause.
- Unwitnessed collapse: provide about 2 minutes of CPR before leaving to activate and obtain the AED. Respiratory causes are common, so early breaths and compressions are especially important.
With two rescuers, one begins CPR while the other activates emergency response and retrieves the AED.
Ratios and depth by age
| Patient | One rescuer | 2 or more healthcare rescuers | Compression depth |
|---|---|---|---|
| Child | 30:2 | 15:2 | At least one-third chest depth, about 2 inches (5 cm) |
| Infant | 30:2 | 15:2 | At least one-third chest depth, about 1.5 inches (4 cm) |
Use a rate of 100-120/min and allow complete recoil for both. Keep interruptions under 10 seconds.
Current infant compression options
The 2025 pediatric guideline uses the heel of one hand or the two-thumb-encircling-hands technique for infant CPR. The older two-finger technique was eliminated because it did not reliably achieve appropriate depth. The two-thumb method is especially useful when two rescuers are positioned for 15:2 CPR, but either current method may be selected based on size and rescuer ability.
AED priority
Use an AED as soon as it is available. For infants and children younger than 8 years, use pediatric pads and a pediatric attenuator when available. If neither is available, use an adult AED rather than withholding defibrillation. Make sure pads do not touch; use anteroposterior placement if necessary.
Common errors
- Treating a newly born infant with the general infant BLS algorithm.
- Using chronological age alone when obvious puberty signs indicate adult BLS.
- Checking an infant carotid pulse instead of brachial or femoral.
- Omitting breaths from pediatric CPR.
- Using 15:2 for a lone rescuer.
- Continuing the retired two-finger infant compression method.
The exam decision starts with the age category, then the number of rescuers. Those two details determine the technique and ratio while rate, recoil, interruption limits, and effective breaths remain universal quality principles.
Choosing the category in a scenario
When an exam stem gives both age and developmental clues, use the BLS definitions rather than legal adulthood. A 10-year-old without puberty signs is treated as a child; a younger adolescent with puberty signs uses adult BLS. A 10-month-old uses infant BLS, while care at the moment of birth belongs to neonatal resuscitation. After choosing the category, immediately identify the matching pulse site, depth, ratio, ventilation interval, and AED-pad option so details are not mixed across algorithms.
Which patient is treated as a child under BLS age definitions?
A person about age 1 who has not reached puberty
A newly born infant
A 6-month-old infant
Every patient younger than 18
What ratio should a lone healthcare provider use for child CPR without an advanced airway?
15:2
30:2
5:1
Continuous compressions with 1 breath every 6 seconds
Which infant compression techniques are current in the 2025 pediatric BLS guidance?
Two fingers only
Both palms over the upper sternum
Heel of one hand or two-thumb-encircling hands
Abdominal compressions
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