Pneumothorax / Meconium aspiration Flashcards
Define pneumothorax
Can occur from RDS (or from the ventilation used to treat RDS) à pulmonary interstitial emphysema
Ventilation-Associated Pneumothorax: to prevent pneumothoraces, infants should be ventilated with the lowest pressures that provide adequate chest movement and blood gasses
Management:
- Immediate decompression
- O2 therapy
- Chest drain if tension pneumothorax
Define meconium aspiration
Meconium aspiration = respiratory distress in the newborn due to presence of meconium in trachea (causing mechanical obstruction and/or chemical pneumonitis -> pneumonia/infection) → occurs exclusively in immediate neonatal period
- 8-20% will pass meconium before birth -> chance of aspiration
- Rare in preterm, increased risk the greater the gestational age
Aetiology
It may be passed in response to foetal hypoxia
Aspyhxiated infants may start gasping before delivery and ASPIRATE the meconium before or at delivery
Meconium is a lung irritant and results in both mechanical obstruction and a chemical pneumonitis as well as predisposing infection
The passage of meconium becomes increasingly common the greater the infant’s gestational age-particularly when post-term
Infants who are acidotic, may inhale meconium and develop meconium aspiration syndrome
Risk factors
- GA >42 weeks
- Maternal history of HTN/PET/smoking/substance abuse
- Fetal distress/hypoxia
- Oligohydramnios
- Meconium stained amniotic flui
- Chorioamnionitis
Presentation
Meconium/dark green staining of the amniotic fluid
Green or blue staining of the skin at birth
Baby appears limp, with low Apgar score
Rapid breathing, laboured or absent
Signs of postmaturity
CTG- foetal bradycardia
The lungs become over-inflated, accompanied by patches of collapse and consolidation
Investigation
Examination
Basic observations
Blood gases, FBC, U&Es
CXR (diagnostic) –> overinflated lungs, patches of collapse and consolidation
* Pneumothorax (from air leak)
* Pneumomediastinum (from air leak)
Management
If normal term infant with meconium-stained amniotic fluid but NO history of GBS- observation is recommended
If there are risk factors or laboratory findings that are suggestive of infection- consider antibiotics
* IV ampicillin AND gentamicin
Oxygen therapy and non-invasive ventilation (e.g. CPAP) may be used in more severe cases
Boluses of surfactant and inotropes are given in moderate cases
AT BIRTH: if the infant cries and establishes regular respiration, no resuscitation is required
If respiration is NOT established, initiating lung inflation within 1st minute of life the PRIORITY.
If baby was born through thick meconium, should inspect oropharynx rapidly and remove any thick meconium by suctioning with a large-bore suction catheter.
If the infant becomes bradycardic, positive pressure ventilation to aerate the lungs is indicated DESPITE the presence of meconium
Complications/ Prognosis
Complications
- There is a high incidence of air leak, leading to pneumothorax and pneumomediastinum.
- Infants may develop persistent pulmonary hypertension of the newborn (this can make it difficult to achieve adequate oxygenation despite high-pressure ventilation)
- Severe meconium aspiration is associated with significant morbidity and mortality
Prognosis
Varies depending on severity- can lead to death if prompt intervention is not provided
May have several neurological disabilities, particularly if experiencing IU hypoxia
Develop reactive airway disease is a long-term effect
Meconium ileus
Meconium ileus = thick, sticky meconium that has a prolonged passing time
o Meconium usually passes within 24hrs of delivery, if not, there may be an ileus
o The child may vomit the meconium instead of passing it as stool
o Associated with Cystic Fibrosis (90%) and biliary atresia
o 1 in 25,000 babies get an ileus
Meconium ileus management:
* 1st line = gastrograffin enema (N-acetylcysteine can also be used)
* 2nd line = surgery
