Neonatal respiratory

Seite 1

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

Seite 2

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)

Seite 3

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 warm

start 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 rate

4. 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. Circulation

After 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

Seite 4

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