Unit
- Structural differences: Infants have smaller airways, narrower nasal passages, and a larger tongue relative to the oral cavity, increasing resistance to airflow and predisposing them to obstruction. The chest wall is more compliant due to cartilaginous ribs and weak intercostal muscles, leading to retractions during respiratory distress.
- Alveolar development: Alveoli continue to form after birth, reaching adult numbers around age 8. This ongoing development affects gas exchange capacity and vulnerability to injury in premature infants. Surfactant production matures around 34 weeks gestation, explaining respiratory distress in preterm neonates.
- Diaphragm role: The diaphragm is the primary breathing muscle in children; intercostal muscles are less effective. Abdominal breathing is normal in infants. Any condition that impedes diaphragmatic movement, such as gastric distension, can significantly compromise ventilation.
- Oxygen consumption: Children have higher metabolic rates and oxygen consumption per kilogram compared to adults, making them more susceptible to hypoxia. Their oxygen reserve is limited due to smaller functional residual capacity, leading to rapid desaturation during apnea or respiratory failure.
- Immature immune system: The pediatric immune system is less developed, increasing susceptibility to respiratory infections. Anatomical factors like shorter Eustachian tubes promote middle ear infections, while lack of prior exposure to pathogens leads to frequent viral illnesses.
- Control of breathing: The respiratory center in the brainstem is immature at birth, resulting in irregular breathing patterns and periodic breathing in neonates. Chemoreceptor sensitivity to hypoxia and hypercapnia evolves during infancy, affecting responses to respiratory stressors.
- Mucociliary clearance: The mucociliary escalator is less efficient in children, especially in the presence of viral infections or conditions like cystic fibrosis. This leads to mucus accumulation and increased risk of secondary bacterial infections.
- Lung volumes: Tidal volume remains relatively constant per kilogram across ages, but functional residual capacity and closing capacity change. Infants have a low functional residual capacity relative to closing capacity, predisposing to airway closure and atelectasis.
- Airway reactivity: Children have heightened airway reactivity compared to adults, making them more prone to bronchospasm from viral infections, allergens, or irritants. This underlies conditions like viral-induced wheeze and asthma, and explains why infants often develop wheezing with respiratory syncytial virus infection.
- Respiratory muscle fatigue: Pediatric respiratory muscles have fewer type I slow-twitch fibers and lower oxidative capacity, leading to earlier fatigue during increased work of breathing. This is particularly relevant in conditions like pneumonia or acute asthma exacerbations, where compensatory efforts quickly exhaust the diaphragm and intercostals.
Scope of Practice
Role: Pediatric Pulmonologist in a Hospital Setting
Within scope:
- Performing comprehensive history and physical examinations focused on respiratory symptoms.
- Ordering and interpreting pulmonary function tests, chest imaging, and sleep studies.
- Developing treatment plans for asthma, cystic fibrosis, and other chronic conditions.
- Coordinating care with respiratory therapists, dietitians, and primary care physicians.
- Educating families on disease management and preventive measures.
Outside scope:
- Performing surgical procedures such as bronchoscopy with biopsy (requires surgical training).
- Administering anesthesia for procedures.
- Providing ongoing primary care for non-respiratory issues.
- Prescribing medications outside of their specialty without consultation.
- Making decisions about terminal weaning from ventilation without ethics committee input.
Quick Revision
- Pediatric airways are narrower and more compliant, increasing obstruction risk.
- Alveolar development continues postnatally, important for preterm infants.
- High metabolic rate and low oxygen reserve make children prone to hypoxia.
- Immature immune system leads to frequent respiratory infections.
Disclaimer
Educational use only. Not intended for practical surgery, incisions, or other surgical procedures. It does not qualify you to perform physical operations.