PEDIATRIC AGE DEFINITIONS & PHYSIOLOGICAL DIFFERENCES
Pediatric patients are not just smaller adults—they have distinct anatomical and physiological characteristics that require specialized assessment, interventions, and resuscitation strategies.
Understanding these key differences is crucial in PALS because:
It guides airway management techniques (e.g., smaller airways, unique positioning needs). It affects medication dosages (weight-based calculations are critical). It influences resuscitation strategies (e.g., oxygenation, circulation support, thermoregulation).
Bottom line? Pediatric emergencies require anticipation and adaptation to prevent rapid deterioration.
PEDIATRIC AGE CLASSIFICATIONS
PALS categorizes pediatric patients into distinct developmental stages, as anatomy, physiology, and medical needs change with age:
| Age Group | Definition | Key Considerations in PALS |
|---|---|---|
| Neonate | Birth to 28 days | High risk of hypoxia, hypothermia, hypoglycemia |
| Infant | 1 month to 1 year | Small airway, rapid respiratory rate, dependent on heart rate for cardiac output |
| Child | 1 year to puberty | Developing immune & metabolic systems, increasing physiologic reserve |
| Adolescent (Adult classification in PALS) | Puberty and older | Managed with adult ACLS guidelines |
Why does this matter?
- Smaller patients = smaller airways, faster metabolic rates, and less physiological reserve.
- Younger children have immature immune systems, making them more vulnerable to respiratory infections and sepsis.
- Older children and adolescents begin to develop more adult-like cardiovascular responses.
KEY PEDIATRIC PHYSIOLOGICAL DIFFERENCES
AIRWAY CONSIDERATIONS
Pediatric airways are narrower, more anterior, and more easily obstructed compared to adults.
Key Differences & Clinical Implications:
Smaller, more anterior airway → Difficult laryngoscopy & intubation. Use the “sniffing position” to optimize airway alignment. Large tongue relative to mouth → Increased obstruction risk. Consider OPA/NPA early if needed. Floppy epiglottis (U-shaped, omega-shaped in infants) → Makes direct visualization harder during intubation. Narrowest point of airway:
- Children <8 years: Cricoid cartilage.
- Adults: Glottis.
- Implication: Uncuffed ET tubes may be preferred in young children to prevent subglottic edema. Obligate nose breathers (Neonates) → Nasal congestion = severe respiratory distress risk!
PALS Takeaways:
- Positioning matters! Use the sniffing position to optimize airway opening.
- Smaller airway structures = faster obstruction. Be proactive in managing secretions & swelling (e.g., croup, epiglottitis).
- Use appropriately sized airway equipment (e.g., smaller ET tubes, OPA/NPA based on age).
RESPIRATORY SYSTEM DIFFERENCES
Children are more vulnerable to respiratory failure because they have fewer oxygen reserves and fatigue faster in distress.
Key Differences & Clinical Implications: Higher respiratory rates:
- Neonates: 40-60 breaths/min
- Infants: 30-40 breaths/min
- Children: 20-30 breaths/min Less Type I muscle fibers in the diaphragm → Faster fatigue in respiratory distress. Smaller functional residual capacity (FRC) → Less oxygen reserve = faster desaturation.
PALS Takeaways:
- Hypoxia is the #1 cause of cardiac arrest in children! Prioritize oxygenation & ventilation in resuscitation.
- Recognize early signs of distress (nasal flaring, retractions, grunting) to intervene before respiratory failure occurs.
CARDIOVASCULAR SYSTEM DIFFERENCES
Children’s hearts work differently from adults—they rely more on heart rate than stroke volume to maintain cardiac output.
Key Differences & Clinical Implications: Higher baseline heart rates:
- Neonates: 120-160 bpm
- Infants: 100-160 bpm
- Children: 80-140 bpm Limited ability to increase stroke volume → They compensate with tachycardia, NOT increased contractility. Bradycardia is often a sign of hypoxia (not primary cardiac dysfunction!).
PALS Takeaways:
- Bradycardia = Hypoxia until proven otherwise! Fix oxygenation first.
- Effective ventilation often reverses pediatric bradycardia without the need for medications.
- Use fluids cautiously! Neonates and infants are prone to pulmonary edema with excessive fluid resuscitation.
METABOLIC & THERMOREGULATORY DIFFERENCES
Children burn through oxygen and glucose faster than adults—and they struggle to regulate body temperature.
Key Differences & Clinical Implications: Higher metabolic rate → Increased oxygen & glucose demand = Higher risk of hypoxia & hypoglycemia. Poor thermoregulation in neonates & infants → Lose heat quickly = risk of cold stress, acidosis, and coagulopathy.
PALS Takeaways:
- Always monitor glucose levels in critically ill children. Hypoglycemia can mimic altered mental status & seizures.
- Prevent heat loss! Use warm blankets, warmed fluids, and heated environments to maintain normothermia.
- Rapid deterioration is common if metabolic needs are not met!
WHY DOES THIS MATTER IN PALS?
Pediatric airway, breathing, circulation, and metabolism differ significantly from adults. Failure to account for these differences can lead to rapid deterioration. PALS focuses on recognizing these unique risks early to prevent avoidable cardiac arrest.
Top Priorities for PALS Providers:
Ensure adequate oxygenation & ventilation to prevent hypoxic arrest. Recognize early warning signs (tachycardia, increased work of breathing). Use age-appropriate equipment and medication dosing. Prevent secondary complications (hypoglycemia, hypothermia).
Takeaway: Pediatric resuscitation is all about anticipation & adaptation. Recognizing these differences early can mean the difference between life and death.