Table 1.

Major characteristics of respiratory physiology in neonates and infants, and their anaesthetic implications

Physiologic characteristics	Anaesthetic implications
Immature control of respiration/Periodic breathing	Preterm infants of <60 weeks postconceptual age have higher risk of postoperative apnoea. Anaesthetics may impair ventilatory response to hypoxia and hypercarbia. Laryngeal stimulation/lung overinflation may produce apnoea.
Smaller, highly compliant airways	Increased airway resistance: Increased work of breathing, Prone to respiratory fatigue. Increased tendency to collapse: Susceptible to airway obstruction.
Higher metabolic oxygen demand/Small Functional Residual Capacity (FRC)	Vulnerable to rapid desaturation.
Unfavourable rib configuration	Greater chest wall compliance. Cannot increase lung capacity during inspiration. Increases workload on the diaphragm.
Inefficient respiratory muscles	Vulnerable to early respiratory fatigue.