--- module: 042-02 language: en chapter: 42 title: "Paediatric and Neonatal Physiology and Assessment" module_title: "Developmental physiology, neonatal transition, and recognition of paediatric deterioration" source_sha256: 46f2d8d38435eebce6464d3a90a7155aee93db8cf5828314a23f9dbc0057ed1f --- # Paediatric development, transition, and deterioration ## Physiology changes with age ### Gestation, postnatal age, growth, puberty ### Infant reserve is small #### High oxygen demand, narrow airway #### Limited stroke volume and glycogen stores ### Watch trajectory before hypotension ## Birth transition and resuscitation ### First breaths replace lung liquid with air #### Pulmonary vascular resistance falls ### Placenta removed: systemic resistance rises ### Foramen ovale closes, ductal flow reverses ### Oxygen and less prostaglandin constrict duct ### Failed aeration or hypoxia keeps fetal shunts #### Severe cyanosis ### Resuscitation is principally respiratory #### Bradycardia follows poor aeration and hypoxia #### Chest rise and heart rate confirm ventilation #### Fix mask, head position, pressure first #### Compressions only for persistent bradycardia ### After resuscitation: glucose, temperature, seizures ### Too little or too much oxygen harms ## Duct-dependent heart disease ### Lesions emerge as the duct closes ### Pulmonary dependence: worsening cyanosis ### Systemic dependence: shock, weak femorals ### Unexplained shock includes heart disease ### Prostaglandin E1 reopens the duct #### Apnoea and hypotension need airway readiness ## Temperature, glucose, and bilirubin ### Temperature is a metabolic intervention #### Evaporation, conduction, convection, radiation #### Brown fat worsens hypoxaemia and acidosis ### Glucose reflects supply, stores, insulin, demand #### Diabetic mothers: persisting hyperinsulinism #### Recurrent need suggests endocrine cause ### Short red-cell lifespan raises bilirubin #### Intestinal deconjugation promotes reabsorption #### Albumin binding limits brain entry ### Conjugated rise signals hepatobiliary disease ## Feeding, growth, and development ### Feeding is a cardiorespiratory task #### Suck-swallow-breathe coordination #### Observe a feed, not reported duration ### Serial weight and sodium detect poor transfer ### Weight fast, length slow, head for brain ### Centile crossing after birth can be normal #### Sustained deceleration warrants evaluation ### Milestone is a probability distribution ### Skill loss worse than slow acquisition ## Respiratory deterioration and airway ### Compensation: rate, recession, grunting #### Sucking competes with breathing ### Fatigue lowers rate and effort #### Quiet child is more dangerous ### Saturation cannot judge ventilation #### Assess carbon dioxide and clinical state ### Escalate on work of breathing, not one number ### Small swelling greatly raises resistance ### Drooling, tripod, muffled voice: supraglottic #### Throat examination can precipitate obstruction ### Foreign body despite normal radiograph ## Circulation, fluids, and dehydration ### Tachycardia and vasoconstriction hold pressure ### Early shock: mottling, slow refill, low urine ### Reassessed weight-based aliquots #### Poor response with liver enlargement, crackles #### Reconsider cardiac and vasoactive support ### Cause-specific fluid strategies ### Oral rehydration uses sodium-glucose coupling ### Controlled sodium correction protects brain ## Fever and prescribing safety ### Young infants may show only poor feeding ### Red flags need urgent assessment at any age ### Antipyretics do not separate viral from bacterial ### Independent calculation chain #### Leading zeros, no trailing zeros ### Liver enzymes and filtration mature separately #### A neonatal dose may later be wrong ### High-risk drugs: three independent checks #### Kilograms versus pounds, daily versus single ### Caregiver demonstrates the syringe volume ## Safeguarding and final assessment ### Injury must fit developmental capability ### Consider bleeding, bone, metabolic mimics ### Record statements close to the words used ### Explain confidentiality limits beforehand ### Not as usual is longitudinal data ### Closed safety plan with named follow-up