--- module: 042-01 language: en chapter: 42 title: "Paediatric and Neonatal Physiology and Assessment" module_title: "Foundations" source_sha256: aeb03f4da139b7c101e05f1d4d4b3a00d02d763a73254f64fdc8dd4551e9ef98 --- # Paediatric and neonatal physiology and assessment ## Children are not small adults ### Anatomy, drugs, disease, measures change with age ### Limited reserve drives rapid progression #### Airway, fluid, glucose, cardiorespiratory limits ### Start with appearance, breathing, circulation, trajectory ### Family-centred care keeps the child's voice and assent ## Transition at birth ### Placenta exchanges gas, shunts bypass lungs ### Aeration lowers pulmonary resistance ### Cord clamping raises systemic resistance ### Left-atrial pressure rises, shunts close functionally ### Disrupted by lung, heart, infection, cold, metabolism ### Duct-dependent lesions worsen as duct closes #### Prostaglandin keeps the duct open #### Apnoea risk needs specialist support ### Resuscitation: warmth, position, dry, then ventilate #### Heart-rate response shows ventilation success #### Compressions and drugs secondary to inflation ## Neonatal physiological reserve ### Rapid heat loss from surface area and thin skin ### Brown fat burns oxygen and glucose #### Cold worsens distress, hypoglycaemia, acidosis ### Glucose shifts from placenta to feeding #### Prematurity, growth restriction, maternal diabetes #### Silent, or jittery, apnoeic, lethargic, seizing ### Haemoglobin falls as erythropoietin decreases ## Neonatal jaundice and feeding ### High red-cell turnover, immature conjugation ### Physiological jaundice after the first day ### Red flags: first day, rapid rise, pale stool #### Haemolysis, infection, liver disease, obstruction ### Unconjugated bilirubin can enter the brain #### Encephalopathy or kernicterus #### Worse with prematurity, acidosis, low albumin binding ### Phototherapy makes bilirubin excretable ### Conjugated jaundice is never physiological ### Assess feeds by attachment, output, weight #### Excess weight loss: hypernatraemic dehydration #### Find barriers without blame ## Growth and development ### Serial velocity beats a single centile ### Faltering growth: intake, loss, demand, neglect ### Milestones are ranges, not deadlines ### Regression worse than isolated mild delay ### Hearing or vision loss mimics global delay ### Early intervention before a final cause ## Age-specific physiology ### Compliant chest, small airways, high oxygen use #### Small radius loss sharply raises resistance ### Recession, flaring, grunting, head bobbing ### Cyanosis is late and pigment-dependent ### Infant output depends on heart rate #### Bradycardia often means hypoxia ### More body water, faster dehydration ### Vasoconstriction preserves pressure until late #### Tachycardia, slow refill, low urine come first ## Nutrition and immunisation ### Breast milk or safe prepared formula ### Deficiency impairs development before signs #### Iron, vitamin D, vitamin B12 ### Obesity can coexist with deficiency ### Vaccination builds memory before exposure ### Mild illness rarely requires delay ### Live vaccines: caution in immune deficiency, pregnancy ## History, observation, and examination ### Observe from a distance first #### Quiet motionless child may be sicker ### History spans birth, development, social setting ### Ask adolescents privately ### Caregivers detect deviation first ### Examine from least to most intrusive ### Reconcile saturation with the child ## Acute patterns and resuscitation ### Croup: stridor at rest signals severity ### Drooling, tripod posture: minimal disturbance ### Bilious vomiting suggests obstruction ### Fever risk is age-dependent #### Antipyretics do not prevent febrile seizures ### Hypoxia commonly drives arrest ### Weight-based, reassessed fluid boluses ### Dose by measured weight, checked independently #### Decimal and unit errors are major hazards ## Safeguarding and communication ### Inconsistent history, implausible injury, delay ### Non-mobile bruising, burns, fractures ### Consider mimics without delaying protection ### Document exact words without accusation ### Seek assent, avoid promises