Paediatric Physiological Differences

Question 1

Physiological differences in the paediatric airway

Answer 1

• Smaller upper/lower airways
• Tongue larger relative to mouth
• Less cartilage (more soft tissue)
• More anterior larynx - sits @ C3-C4
• Floppy epiglottis angled away from trachea
• Cricoid cartilage part of airway
• Larger anatomical dead space

Question 2

Physiological differences in the paediatric breathing

Answer 2

• Less lung reserve
• Chest wall softer and more flexible - ribs move horizontally
• Underdeveloped intercostal muscles (diaphragm dominant)
• Less and smaller alveoli - less SA for GE
• Higher RR due to higher metabolic rate
• Less elastic tissue in lungs (alveoli have more difficulty staying open at end of breath - more prone to collapse)

Question 3

Physiological differences in the paediatric circulation

Answer 3

• Less compliant myocardium
• Higher CO
• Greater % of total body is water
• Incompletely developed nervous system (more sensitive to vagal stimulus)
• Children are unable to increase SV so they must increase HR to increase CO

Question 4

Physiological differences in the paediatric disability

Answer 4

• Large head causes gravity displacement
• Softer bones
• Incomplete myelination and brain development < 6 years
• Susceptible to effects of hypoxia, hypotension, seizures and hyperthermia
• Cerebral tissue is thinner, softer and more flexible
• Neck prone to subluxation
• Susceptible to minor volume changes from bleeding and oedema
• Fontanelle
• Large occiput - head flexed in neutral position