Neonatal respiratory distress Flashcards
Name 4 symptoms/signs of neonatal respiratory distress
Tachypnoea (> 60/min)
Increased WOB
Noisy breathing (stridor, wheeze, grunt)
Central cyanosis
Is a blue newborn always a pathological thing? Why/why not? If not, at what point should you start to worry?
No - babies are often blue when first born as foetus only has SaO2 around 60% in utero. Start to worry when SaO2 3 minutes after delivery
Name 2 transient causes of neonatal respiratory distress
Post-asphyxia
Hypo/hyperthermia
Name 4 causes of neonatal respiratory distress in a term infant. Which is most common? Most dangerous?
Wet lung (Transient Tachypnoea of Newborn) - most common
Pneumonia - most dangerous
Meconium aspiration
Other (congenital heart defect, space occupying lesion)
HMD rare
Name 2 agents of neonatal pneumonia. What 2 antibiotics are usually used to treat?
Group B strep
Gram-negative bacilli
Use IV ben pen and gent
What causes transient tachypnoea of the newborn? What physiological factors affect this? What is its usual clinical course?
Imbalance in fluid production and removal of foetal lung liquid (continued production and delayed removal)
Adrenaline release on activity suppresses lung liquid production. Lymphatics and mechanical pressure of breathing remove fluid from lung.
Should improve over hours - days
Why might a newborn get meconium aspiration? Name 3 complications of meconium aspiration in a newborn. How do you manage it?
Can aspirate from gasping on initiation of breathing after delivery.
Complications:
Block airways
Irritate lungs (pneumonitis)
Potentiate infection
Management - suction from level of trachea
What is the different outcomes of a complete vs incomplete airway blockage by meconium aspiration?
Complete = distal collapse Incompete = air gets in (opens on inspiration) but not out = overinflation, pneumothorax
Go through the appearance on CXR of pneumonia, TTN and meconium aspiration of a newborn
Pneumonia - diffuse opacification
TTN - fluid in fissures
Meconium aspiration - overdistension (incomplete block), collapse (complete block), consolidation
Is meconium more likely to happen in an extreme preterm baby or a post-dates baby? Why?
Post-dates - the older the foetus, the more meconium it makes.
Name 3 diseases that can cause respiratory distress in a pre-term infant. Which is most common, and which is most dangerous?
HMD - most common
Pneumonia - most dangerous
Wet lung
Meconium aspiration unlikely
What role does surfactant have in lung function? When is it mostly released and what stimulates its release?
Reduces surface tension to stop alveoli from collapsing. Released mostly between 34-35 weeks after steroid release (but present from 22-24 weeks)
Name 3 pathophysiological processes that result from lack of surfactant release/HMD. Name 2 appearances of HMD on CXR
Increased surface tension = alveolar collapse = atelectasis
Can also result in leakage of proteins (= hyaline membrane in respiratory bronchioles) and fluid (= fluid on lung)
CXR - ground-glass appearance and/or collapsed lung
What is the positive feedback cycle that leads to severe HMD?
Surfactant deficiency = atelectasis = V/Q mismatching and shunting = pulmonary vasoconstriction = reduced alveolar type II cell metabolism = further surfactant deficiency
Name 5 risk factors for HMD
Prematurity Asphyxia Maternal DM Second twin Male FHx
