January 10th, 2018
Physiological and Anatomical Differences between Children and Adults
Children and adults differ in their developmental, anatomical and physiological features thus presenting a need to modify treatment approaches when attending to children. Such differences increase children’s vulnerability to injuries and environmental hazards, with management of the resultant conditions requiring paediatric-specific pharmaceuticals and equipment. Since children’s tissues are in a phase of active and rapid growth, effective medical treatment may offer a better chance of recovery compared to adults. As such, knowledge of anatomical and physiological differences between children and adults helps to develop treatment approaches suited for paediatric clients.
Anatomical and physiological differences between children and adults occur in areas such as airway and respiratory system, cardiovascular system and central nervous system. In respect to airway and respiratory system, anatomical differences in a child airway compared to an adult’s airway include a smaller diameter, smaller-sized nostrils, thinner pharynx and larynx, slenderer nasopharynx, and shorter turbinate region (Santillanes & Gausche-Hill, 2008; Xi, Si, Kim & Berlinski, 2011). Such anatomical differences present challenges in managing a child’s airways in the event of injury or medical procedures. For instance, a smaller diameter leads to increased airway resistance and, as such, increases the child’s susceptibility to respiratory failure (Santillanes & Gausche-Hill, 2008). Other differences such as a larger occiput and a proportionally larger tongue in the child makes them susceptible for airway obstruction, especially when lying on a flat surface in supine position (Santillanes & Gausche-Hill, 2008). Further, high soft tissue content and higher flexibility of the trachea in children poses a threat of obstruction, which could result from tracheal collapse following external pressure for example during cricoid pressure (Santillanes & Gausche-Hill, 2008). Moreover, unlike adults whose narrowest airway part is at the vocal cords, children’s narrowest part is at the cricoid ring (Santillanes & Gausche-Hill, 2008), which could present challenges when inserting an endotracheal tube.
Other respiratory anatomical differences between children and adults are present in areas such as intercostal muscles and diaphragm. For instance, the concentration of slow-twitch skeletal muscle fibres is lower in children’s intercostal muscles and diaphragm predisposes them to respiratory failure (Santillanes & Gausche-Hill, 2008). Children’s susceptibility to respiratory muscle fatigue also arises with lower deposits of glycogen and fat in such muscles (Santillanes & Gausche-Hill, 2008). Further, children have a flatter diaphragm and more horizontal ribs compared to adults (Santillanes & Gausche-Hill, 2008).
The anatomical differences affect various physiological functions in children. For instance, the flatter diaphragm and more horizontal ribs have a positive effect on children’s functional residual capacity, but curtail children’s ability to increase tidal volume when necessary e.g. following a change in respiratory rate (Santillanes & Gausche-Hill, 2008). Such a case is exemplified in the event the children need to increase minute ventilation following increased demand for oxygen. In this way, to increase minute ventilation, a multiple of respiratory rate and tidal volume, infants need to increase the respiratory rate, which, however, is limited by the tidal volume capacity (Santillanes & Gausche-Hill, 2008). As such, the infants will usually have less reserve and be more vulnerable to respiratory failure. Further physiological differences arise from aspects such as children’s preference to use the nose for breathing. Such preference for the nose implies that breathing through the mouth requires learning and, as such, before such learning occurs, aspects such as nasal secretions may create airway obstruction challenges (Santillanes & Gausche-Hill, 2008). Further, during sleep, sedated states, and apnoeic states, infants may have challenges maintaining functional residual capacity, which in fully awake infants is ensured by the slightly inspiratory state of the respiratory muscles (Santillanes & Gausche-Hill, 2008).
Go to part 2 here.