Neonatal respiratory

Adult vs pediatric physiology respiratory system Lungs go from being fluid filled to air filled Lungs take over role of oxygen exchange Respiration commences when lungs become filled with air and fluid is absorbed Fall in right ventricle pressure as lungs expand and pulmonary vascular resistance is reduced

Adult vs pediatric physiology CVS system Change from foetal to neonatal circulation Relaxation of smooth muscle in pulmonary blood vessels --> triggered by entry of O2 into lung with first breath At birth 3 shunts cease to function: these include the loss of the loss of placental circulation (cord clamping and collapse of umbilical vessels therefore collapse of ductus venosus) --> increase in TPR Lung fluids cleared and onset of gas exchange for ventilation --> increase in oxygen and decrease in Co2 with distension of lungs as they fill with air --> there is also decrease in pulmonary vascular resistance and pulmonary artery --> and there is more pressure within the left atrium compared to pressure in right atrium (as TPR > Pulmonary resistance) --> cessation of shunt through foramen ovale Reversal of flow in the ductus arteriosus (closes to prevent high volume LV failure)

Adult vs pediatric physiology fluid and electrolyte metabolism Total body water is 80% at term --> which drops to 60% at 12 months Active neonates requires twice as much water as a nick neonate (100mls/kg/day or 4mls/kg/hour) Avoid hypernatraemia or hyponatraemia --> that latter is usually due to water excess Avoid hypoglycaemia (decreases cardiac function as well as brain); probably best to use isotonic maintenance fluids especially in situation associated with water retention like post-op and stress situations

Adult vs pediatric physiology immune system Immature immune system in paediatrics and it relies heavily on the transfer of placental IgG and after that via breast milk This places them at high risk of sepsis

Adult vs pediatric physiology thermoregulation Normothermia 36.5-37.5 Hypothermia --> bradycardia Poor heat production --> no shivering or behavioural response

Revise the components of the Apgar scoring system and be able to assess a newborn baby Appearance: 0 (white); 1 (blue); 2 (pink) Pulse: 0 (< 60); 1 (60-100); 2 (>100) Grimace (response to stimulation: 0 (none); 1 (grimace); 2 (cry) Activity: 0 (limp/none); 1 (poor/flexion); 2 (good/ active) Respiratory: 0 (none); 1 (gasping, moderate/irregular); 2 (vigorous,crying) 7-10: neonate is well --> no management is required 5-7: mild birth asphyxia --> gentle suctioning of nose, mouth and pharynx, stimulation 3-4: moderate asphyxia --> bag-mask ventilation with oxygen; ABGs; if ph > 7.25 (administer Hco3-) 0-2 (severe asphyxia) --> urgent CPR; intubation; IPPV with oxygen; umbilical vein catherisation; Hc03- (1-2meq/kg); IV colloids (albumin 10ml/kg); trasnsfter to NICU (nets will advise and assist in transport where required)

Know the key clinical parameters in the assessment of the newborn infant and be able to implement appropriate resuscitation measures based on these clinical parameters 1. Prepare for delivery Turn on radiant warmer; ensure all equipment is ready and working; start oxygen and low flow suction; ensure intubation equipment is ready 2. Temperature control - dry, wrap & keep baby warmstart timer; dry baby immediately after delivery - cover head and body with warm towel (remove wet blankets); place under radiant warmer (out of draught in a warm delivery room); hypothermia (increase in oxygen consumption --> decrease in oxygen tension --> metabolic acidosis and hypoglycaemia + inhibits production of surfacatant)3. Assess babies condition APGAR --> appearance, pulse, grimmace, activity, resp rate4. Airway Head in neutral position (don't over extend or flex neck) --> collapse babies pharyngeal airway --> slight flexion with extension at the atlanto-occipital joint (sniffing the night air); jaw thrust to bring babies tongue forward and open airway Suction --> if blood, mucus, foreign material in the mouth Not 5 cm past lips --> only under direct vision with laryngoscope Guedel airway + PPV or facial mask with oxygen Consider intubation if apnoeic Stimulate baby by slapping feet and rubbing 5. Breathing First 5 breaths = inflation breaths (2-3 s breaths) If air is not available then use oxygen. Ensure complete seal of face. Should be giving oxygen at 5-10L/min Delivery rate is 40-60 bpm On arrival of an adquately trained doctor, intubation should be performed if ncessary 6. CirculationAfter 15-30 seconds of effective mask ventilation; assess brachial or umbilical pulse; HR < 60 bpm and not improvement then commence compressions (HR > 100); CPR; CR 7. Drugs Adrenaline; dextrose; Na bicarb; volume expansion; naloxone

Revise the assessment and management of respiratory distress syndrome in newborns and outline the key clinical parameters that would require transfer to a neonatal intensive care unit Tachypnoea (RR > 60) Intercostal and subcostal recession (excessive use of accessory muscles of respiration) Sternal and rib retraction Flaring of nasal nares Grunting Cyanosis Apnoea Tracheal tug Lethargy, pallor, bradycardia, apnoea (may be the first signs in young children) CXR (as normal breath sounds can be heard in auscultation) Causes Respiratory HMD; meconium aspiration syndrome; TTN; congential pneumonia; pneumothorax; hydro/hemothorax Upper airway abnormalities/ upper airway obstruction laryngomalacia; micrognathia; vocal cord anomalies; choanal atresia Lower airway obstruction --> Tracheomalacia; tracheal stenosis; vascular stenosis; bronchiolar obstruction Cardiac anomalies --> heart failure; mycoarditis; pericardial effusion; transpoistion of great arteries Structural abnormalities --> diaphragmatic hernia; congential cystic lesions; diaphragmatic paralyssis Chest deformities --> arthrohryposis; thoracic dystrophy Haematological causes --> anaemia CNS lesions --> Infections Metabolic conditions --> metabolic acidosis Meconium Aspiration Syndrome (MES) - early onset of respiratory distress (within 2 hours) and hypoxaemia in a meconium stained infant due to passage of meconium at or prior to delivery. Commonly occurs at term or frequently: Tachypnoea; cyanosis; hyperinflation Inspiratory crackles; expiraotyr noises may be present Global atelectasis; widespread opacification accompanied with hyperfinaltion and/ or atelectasis O2; suctioning; nasal CPAP; intubation and PPV; fluid restriction; antibiotic therapy; IV therapy Hyaline Membrane disease/ Respiratory distress syndrome 6 hours of birth --> worse after 12- 72 hours --> preterm infants; low gestational age. Incidence increases with decreasing gestation; RDS due to immaturitiy of surfactant and fluid clearance --> therefore lungs cant expand evenly or evenly) -->Grunting; intercostal recession; nasal flaring; cyanosis; increased oxygen reequirements ground glass; respiratory support with oxygen; assisted ventilation CPAP and IPPV and surfactant therapy; keep them warm; 10% dextrose if not feeding