Neonatology - Meconium Aspiration Flashcards
Definition
Meconium = dark green, sticky, and lumpy faecal material = produced during pregnancy.
It is usually released from the bowels after birth but in 8-25% of pregnancies, the baby can pass meconium in-utero
When babies aspirate they can develop respiratory distress
Pathophysiology
The peristalsis usually is the result of foetal hypoxic stress of vagal stimulation due to cord compression.
However, once aspirated it can stimulate the release of many vasoactive and cytokine substances that activate inflammatory pathways, as well as triggering vasculature changes.
It also inhibits the effect of surfactant in the lungs.
It can cause infection.
Risk factors
- In utero growth restriction (IUGR)
- Maternal hypertension, diabetes. pre-eclampsia or eclampsia, smoking and drug abuse
- Gestational Age > 42 weeks
- Foetal ditress (tachycardia/bradycardia)
- Intrapartum hypoxia secondary to placental insufficiency
- Thick meconium particles
Clinical features
- Tachypnoea - a respiratory rate of > 60 breaths per minute
- Tachycardia - a heart rate of > 160 beats per minute
- Cyanosis - this requires immeadiate management
- Grunting
- Nasal flaring
- Recessions = intercostal, supraclavicular, tracheal tug
- Hypo tension - systolic blood pressure < 70 mmHg
Investigations
Chest X-ray: A plain radiograph will often show:
- Increased lung volumes
- Asymmetrical patchy pulmonary opacities
- Pleural effusions
- Pnuemothorax or pneumomediastinum
- Multifocal consolidation - due to chemical pneumonitis
FBC
CRP
Blood cultures
ABG - metabolic acidosis
DDx
- Transient tachypnoea of the newborn
- Surfactant deficiency
- Persistant pulmonary hypertension
Treatment
Observations
Keep infant warm
Monitor and take bloods
IV fluids
Oxygen and ventilation
Abx
Surfactants
Inhaled NO
Corticosteroids
Complications
Air leak
- “ball-valve” effect, air leaks can occur due to alveolar hyperdistention leading to a pneumothorax or a pneumomediastinum
Cerebral palsy
- cerebral hypoxia
