Neonatal respiratory problems Flashcards
What are 6 signs of respiratory distress in newborn infants?
- Tachypnoea (>60 RR)
- Laboured breathing
- Chest wall recession (particularly sternal and subcostal indrawing)
- Nasal flaring
- Expiratory grunting
- Cyanosis if severe
What is the definition of tachypnoea in a neonate?
>60 bpm
What is the commonest cause of respiratory distress in term infants?
transient tachypnoea of the newborn
What are 2 groups of causing of respiratory distress in term infants?
- Pulmonary
- Non-pulmonary
What are 7 pulmonary causes of respiratory distress in term infants?
- Transient tachypnoea of the newborn
- Meconium aspiration
- Pneumonia
- Respiratory distress syndrome
- Pneumothorax
- Persistent pulmonary hypertension of the newborn
- Milk aspiration
What are 5 rare causes of respiratory distress in term infants?
- Diaphragmatic hernia
- Tracheo-oesophageal fistula
- Pulmonary hypoplasia
- Airways obstruction e.g. choanal atresia
- Pulmonary haemorrhage
What are 4 non-pulmonary causes of respiratory distress in term infants?
- Congenital heart disease
- Hypoxic-ischaemic/ neonatal encephalopathy
- Severe anaemia
- Metabolic acidosis
What are 5 investigations that must be performed on all newborn infants with respiratory distress?
- Monitor heart rate
- Monitor respiratory rate
- Monitor oxygenation
- Monitor circulation
- Chest x-ray - to help identify cause needing immediate treatment e.g. pneumothorax or diaphragmatic hernia
What is the management of all infants with respiratory distress?
- Admit to neonatal unit
- Additional ambient oxygne, respiratory support as required
- non-invasive: CPAP or high-flow nasal cannula therapy
- mechanical ventilation and circulatory support
What causes transient tachypnoea of the newborn?
delay in the resorption of lung liquid
What factor increases the likelihood of transient tachypnoea of the newborn?
caesarean section
What are 2 types of causes of respiratory distress in neonates that can be identified by x-ray and require immediate treatment?
- Pneumothorax
- Diaphragmatic hernia
What may be seen on the chest x-ray in transient tachypnoea of the newborn?
fluid in the horizontal fissure
What management of transient tachypnoea of the newborn may be required?
additional ambient oxygen
What is the usual outcome of transient tachypnoea of the newborn?
usually settles wtihin first day of life, can take several days to resolve completely
How is a diagnosis of transient tachypnoea of the newborn made?
after consideration and exclusion of other causes such as infection
In what proportion of babies is meconium passed before birth?
8-20% (rarely by preterm infants)
What increases the likelihood of passing meconium before birth?
greater gestational age (20-25% by 42 weeks)
What can trigger the passing of meconium?
may be passed in response to fetal hypoxia
How does aspiration of meconium come about?
asphyxiated infants may start gasping and aspirate meconium before or at delivery
What are 3 effects of meconium aspiration?
- Mechanical obstruction
- Chemical pneumonitis - irritant to the lungs
- Predisposes to infection
What are 3 things that may be seen on chest x-ray in meconium aspiration?
- Overinflation of lungs
- Patches of collapse and consolidation
- High incidence of air leak, leading to pneumothorax and pneumomediastinum
What management of meconium aspiration is often required?
Mechanical ventilation
What complication can develop as a result of meconium aspiration?
persistent pulmonary hypertension of the newborn
What difficulty can persistent pulmonary hypertension lead to in the management of a newborn with meconium aspiration?
may make it difficult to achieve adequate oxygenation despite high-pressure ventilation
How serious is meconium aspiration?
serious - associated with significant morbidity and mortality
How effective is aspiration of meconium from an infant’s oropharynx immediately after delivery of head/ removal by intubation+ tracheal suctioning in meconium aspiration?
no evidence that it reduces incidence or severity of meconium aspiration
What are 3 factors which predispose to pneumonia in the neonate?
- Prolonged rupture of membranes
- Chorioamnionitis
- Low birthweight
What is the usual investigation to identify any infection as a cause of respiratory distress in the newborn?
CXR, blood cultures
What is the management of pneumonia in the newborn?
broad-spectrum antibiotics until results of infection screen are available
In what proportion of deliveries may a pneumothorax occur spontaneously?
2%
What symptoms can pneumothorax produce?
usually asymptomatic but can cause respiratory distress
What are 4 causes of pneumothorax in the newborn?
- Spontaneous
- Meconium aspiration
- Respiratory distress syndrome
- Complication of mechanical ventilation
What is the management of pneumothorax?
tension pneumothorax treated urgently with decompression by inserting chest drain
What are 2 ways to confirm the diagnosis of pneumothorax?
- Transillumination with bright fibre-optic light source applied to the chest wall
- Chest x-ray
What are 5 risk factors for milk aspiration in the newborn, causing respiratory distress?
- Preterm infants
- Respiratory distress
- Neurological damage
- Bronchopulmonary dysplasia - often have GORD which predisposes to aspiration
- Cleft palate
What are 4 conditions that can predipose to persistent pulmonary hypertension of the newborn?
- Birth asphyxia
- Meconium aspiration
- Sepsis
- RDS
- Sometimes occurs as primary disorder
What happens in persistent pulmonary hypertension of the newborn?
- as a result of high pulmonary vascular resistance, there is right-to-left shunting within the lungs and at atrial and ductal levels
What are 2 features of presentation of persistent pulmonary hypertension of the newborn?
- Cyanosis soon after birth
- Heart murmurs and signs of heart failure often absent
What are 2 investigations required for persistent pulmonary hypertension and what will they show?
- Chest x-ray: normal size heart, pulmonary oligaemia
- Urgent echocardiogram: exclude congenital heart disease, identify signs of pulmonary hypertension: raised pulmonary pressures, tricuspid regurgitation
What are 2 signs of persistent pulmonary hypertension of the newborn on the echo?
- Raised pulmonary pressures
- Tricuspid regurgitation
What are 6 treatment aspects for persistent pulmonary hypertension?
- Mechanical ventilation
- Circulatory support
- Inhaled nitric oxide - potent vasodilator
- Sildenafil (Viagra) - vasodilator
- High-frequency or oscillatory ventilaion
- Extracorporeal membrane oxygenation (ECMO)
When is ECMO indicated for persistent pulmonary hypertension?
severe but reversible cases, but only performed in a few specialist centres
What does extra-corporeal membrane oxygenation (ECMO) involve?
infant placed on heart and lung bypass for several days
How are many diaphragmatic hernias diagnosed?
antenatal ultrasound screening
What are 2 ways that diaphragmatic herniation may present?
- Respiratory distress
- Failure to respond to resuscitation
What happens anatomically in most cases of diaphragmatic herniae?
left-sided herniation of abdominal contents through the posterolateral foramen of the diaphragm
On examination what are 3 signs of diaphragmatic hernia?
- Displaced apex beat to right of chest
- Displaced heart sounds to right of chest
- Poor air entry in left chest
What can vigorous resuscitation for diaphragmatic hernias result in and why?
can result in a pneumothorax and worsening of situation
How is diagnosis of diaphragmatic hernia confirmed and what will it show?
chest x-ray: loops of bowel in the left chest and displacement of the mediastinum.
What are 4 aspects of management of a diaphragmatic hernia?
- Once diagnosis suspeced, large NG tube passed, apply suction to prevent distension of intrathoracic bowel
- Repaired surgically after stabilisation
What is the main problem associated with a diaphragmatic hernia in most infants?
pulmonary hypoplasia due to compression by herniated viscera preventing development of lung in fetus
What causes mortality from diaphragmatic hernia to be high?
hypoplastic lungs
What are 2 signs that heart failure is the cause of respiratory distress in the newborn?
- abnormal heart sounds and/or heart murmurs
- enlarged liver from venous congestion
What physical sign on examination must you look for in every infant with respiratory distress and why?
Femoral pulses: coarctation of aorta and interrupted aortic arch are important causes of heart failure in newborn infants
