Differences Between Children & Adults Flashcards
What are the differences in the airways in children compared to adults?
Large head, short neck and prominent occiput (back of the head)
Larynx is high and anterior (C3-C4)
Neonates preferentially breathe through their nose
Epiglottis is long, stiff and flops posteriorly
Narrow nasal passages are easily blocked with secretions
Airway is funnel shaped and narrowest at level of cricoid cartilage
Trauma to the airway easily results in oedema
What are the differences in the respiratory system between children and adults?
Neonates and infants have a limited respiratory reserve
Horizontal ribs limit and increase in tidal volume
Ventilation if primarily diaphragmatic
Chest wall is significantly more compliant than that of an adult
Functional residual capacity is low
Minute ventilation is rate dependent = little means to increase tidal volume
Alveoli are thicker walled and only 10% of total number of adult alveoli are found in infants (develop over first 8 years)
What are the differences in the cardiovascular system between children and adults?
Myocardium is less contractile = ventricles less compliant and less able to generate tension during contraction
Stroke volume is limited = cardiac output is rate dependent
Infant behaves as with a fixed cardiac output state
Vagal parasympathetic tone is the most dominant = neonates and infants more prone to bradycardia
Bradycardia associated with reduced cardiac output
What are the differences in the renal system between children and adults?
Renal blood flow and GFR are low in first 2 years of life due to high renal vascular resistance
Tubular function is immature until 8 months = infants unable to excrete a large Na+ load
Large losses due to large surface area to weight ratio
Urine output = 1-2ml/kg/hr
How does hepatic processing differ in a child?
Liver function is initially immature because of decreased function of hepatic enzymes
How is glucose metabolism different in a child?
Hypoglycaemia is common in the stressed neonate
Glucose levels should be monitored regularly
Glycogen stores are in the liver and myocardium
How is haematology different in a child?
Children more prone to sickle cell disease
Less 2,3-DPG so HbF released easily
Vitamin K dependent clotting factors (II, VII, IX, X) and platelet function are deficient in the first few months
Why is vitamin K given at birth?
To prevent haemorrhagic disease of the newborn as they lack vitamin K dependent clotting factors (II, XII, IX, X)
Why is temperature control poor in children?
Babies have a large surface area to weight ratio
Minimal subcutaneous fat
Poorly developed shivering, sweating and vasoconstriction mechanisms
Brown fat is located in small amounts and its metabolism is required for non-shivering thermogenesis, but more O2 is required
How is the CNS different in children, to adults?
Neonates demonstrate pain by increased HR, BP and neuroendocrine response
BBB is poorly formed
Drugs cause BBB more easily = prolonged and variable duration of time
Cerebral vessels are thin walled and fragile
Prone to interventricular haemorrhages
Risks: hypoxia, hypercarbia, hypernatraemia, low haematocrit, awake airway manipulations, rapid bicarbonate administration, fluctuations in blood pressure and cerebral blood flow
