Features
Implications
- Limited respiratory reserve due to fatigable muscles, differing respiratory mechanics, increased dead space and reduced functional residual capacity (FRC)
- ‘Sniffing the morning air’ position will not help bag mask ventilation or visualisation of the glottis
- Head needs to be in a neutral position.
- Ventilation is primarily diaphragmatic
- Diaphragm is relatively horizontal rather than dome shaped
- Bulky abdominal organ which can easily splint the diaphragm
- FRC decreases with apnoea and anaesthesia
- Stomach insufflation due to poor bag-mask ventilation can splint the diaphragm - nasogastric tube decompression can significantly improve ventilation
- Contributes to limited respiratory reserve
- Horizontal ribs prevent the ‘bucket handle’ action seen in adults
- Limits ability to increase tidal volume
- Important to vary ventilatory rate according to age of the child
- Contributes to limited respiratory reserve
- Chest wall is significantly more compliant than that of an adult
- FRC is relatively low
- Closing volume is larger than FRC until 6-8 years
- Reduced time to desaturation during apneoa
- Prone to atelectasis - PEEP increases increases lung volumes and reduces the risk of atelectasis during anaesthesia
- Contributes to limited respiratory reserve
- Work of respiration may be up to 15% of oxygen consumption
- Muscles of respiration contain low levels of type 1 muscle fibres when immature
- Easily prone to fatigue
- Contributes to limited respiratory reserve
- Physiological dead space is around 30% and may be significantly increased by anaesthetic equipment
- CPAP improves oxygenation and reduces work of breathing during spontaneous ventilation
- Prone to rebreathing during invasive ventilation - apparatus dead space and resistance should be kept to a minimum
- Respiratory centre is relatively immature
- Neonates and young infants have irregular respirations and are at a greater risk of apnoea
- Apnoeas may be a manifestation of significant systemic disease in neonates and young infants
- Apnoeas are common postoperatively in premature infants - vigilant monitoring required