Anatomical and Physiological Differences in Children
Any paediatrician will tell you that anatomically and physiologically a child is not simply a small adult. It is for this reason that paramedics often find themselves uncomfortable treating children, because all of the normal physiological values differ and basic anatomical positioning must be changed to meet these differences. This page identifies the basic anatomical and physiological differences in children that paramedics should be aware of.
Airway Assessment in Children
A child’s airway is obviously much smaller than an adult, but the differences go further than basic size.
For example:
– An infant is an obligatory nose breather for the first 6 months, which means that a blocked nose can lead to respiratory failure!
– Infants have very short and softer tracheas than adults. This means that overextension during airway manoeuvres may result in airway collapse (not too dissimilar to kinking a narrow garden hose).
– Tonsils and adenoids grow disproportionately fast in children, making any inflammatory response more likely to compromise the movement of air. Tonsillitis can be a life threatening infection for a child as opposed to an annoyance to an adult.
– Infants have proportionately large heads, short necks and large tongues, which again, makes airway obstruction more likely.
– Both infants and even toddlers have a long and floppy epiglottis, which means more chance of airway obstruction.
Assessing a child’s airway involves looking for patency. A crying or talking child indicates at least a certain amount of patency.
Airway manoeuvres in children should primarily include the head tilt-chin lift technique and avoid overextension of the neck.
Assessing Breathing in Children
The following are important differences between an adult and a child’s breathing:
– A child has much small upper and lower airways which results in a great chance of respiratory difficulties and failure.
– Infants are abdominal breathers who rely primarily on the muscles of the diaphragm. This means abdominal distension can lead to respiratory problems.
– The immature muscles associated with respiration, such as the diaphragm, intercostal muscles and sternocleidomastoid are more likely to fatigue.
– The respiratory centre is relatively immature. This means that neonates and young infants have irregular respirations and are at a greater risk of apnoea. Many neonates will literally feed and forget to breathe.
The following is a rough guide for respiratory rates in healthy children:
Neonates: 30-60
Infants: 30-40
Toddlers: 20-40
Young Children: 20-30
Older Children: 15-20
Warning signs in children with respiratory problems include:
– Nasal flaring and head bobbing in children infants with respiratory distress.
– Chest wall recession indicates severe respiratory effort.
– Tracheal tug, which is identified by a downward pull of the trachea during inspiration.
– Sternal recession, which is associated with severe respiratory distress.
– Grunting is a sound made by neonates and associated with expiration against partially closed vocal cords is a sign of severe respiratory distress.
– Gasping is a sign of severe hypoxia and is often pre-terminal or respiratory arrest.
Remember, children have underdeveloped muscles associated with respiration and are consequently more prone to fatigue.
Assessing Circulation in Children
Children generally have very good cardiovascular health. This enables them to compensate well for circulatory problems such as hypervolemia and dehydration. There will rarely be a change in a child’s blood pressure until it is about to have a cardiac arrest.
The heart rate of a child makes a better diagnostic tool.
Tachycardia is a sign of hypervolemia, and although the heart muscle is capable of prolonged rates in excess of 200 beats per minute, if the cause of the hypervolemia is not detected and treated, the child will eventually become bradycardic and have a cardiac arrest.
Bradycardia is a pre-terminal event in children.
The following are basic heart rate guidelines for children:
Neonate: 110-160
Infant: 100-160
Toddler: 90-140
Small Child: 90-120
Older Child: 60-100.
Assessing a Child’s Neurological Status
A child’s behaviour and general appearance needs to be assessed during a neurological assessment. A child’s behaviour should be compared to what is normal for that child. Use the parents and ask them to compare the child’s presentation with his or her normal general appearance.
– An infant will normally track their eyes to follow motion.
Assessing a Child’s Temperature
Neonates and infants lose heat more rapidly than adults because the surface area on their heads is larger by comparison to their body mass. Also, young children have an undeveloped hypothalamus, which means that their ability to regulate temperature is impaired.