Respiratory disease in a neonate: Chronic Lung Disease (CLD) of prematurity Flashcards
Define chronic lung disease of prematurity.
Oxygen requirement at corrected age of term with characteristic radiological changes (also known as bronchopulmonary dysplasia).
Explain the aetiology of chronic lung disease of prematurity.
Multifactorial in pathology:
- Volutrauma and barotraaumas secondary to positive pressure ventilation (PPV).
- High inspired oxygen concentration (> 40%); toxic to the immature lung.
- Activation of inflammatory mediators (secondary to free radicals, barotraumas and infection).
- Inadequate nutritional supplement
What is a related condition to chronic lung disease of prematurity?
Respiratory distress syndrome (RDS)
What is the pathophysiology of chronic lung disease of prematurity?
Theory of oxygen-mediated lung injury: Results from the generation of superoxides, hydrogen peroxide and oxygen free radicals which disrupt membrane lipids.
Histopathology: Interstitial oedema, muscosal metaplasia, interstitial fibrosis, overdistended alveoli.
Summarise the epidemiology of chronic lung disease of prematurity.
Inversely related to gestation and birthweight.
Increased incidence secondary to increased survival of very lowbirthweight infants.
What are the signs and symptoms of chronic lung disease?
Most properly managed neonates are asymptomatic as they are given ventilator support, but some CLD babies may have some chronic recession.
Poor weight gain with increased energy intake.
What are appropriate investigations for chronic lung disease of prematurity?
ABG: Compensated respiratory acidosis reflecting chronic high pCO2.
CXR: Characterisitc hyperinflation and cystic changes. Used to determine severity, and distinguishes CLD from atelectasis, pneumonia and air-leak syndrome.
What is the management of chronic lung disease?
General: Factors such as PPV and oxygen therapy that cause bronchopulmonary dysplasia are necessary for survival in preterm infants; therefore management is primarily about minimisation of risk.
Ventilation: Oxygen toxicitym barotraumas and voluntrauma can be minimised by strict monitoring and maintenance of pH, pCO2 and pO2 within small ranges dependent on age of preterm infant. There is no evidence that highfrequency ventilation is superior to conventional in prevention.
Nutritional support: Early parenteral nutrition. Maximisation of the nutritional intake prevents further lung injury and aids tissue repair.
How is chronic lung disease of prematurity prevented?
Surfactant within 2 hours with early extubation to nasal CPAP for the treatment of RDS decreases incidence of CLD.
Use of steroids to prevent CLD is highly controversial as it has been shown to have an adverse affect on neurodevelopmental outcome. Steroids are generally only used in ventilator-dependent neonates who are ‘stuck’ on the ventilator.
What is the long term management of chronic lung disease of prematurity?
Home O2 supported by community children’s nurses; ‘Hospital at home’ team.
What are complications associated with chronic lung disease of prematurity?
Pulmonary hypertension which leads to cor pulmonale, increase risk of respiratory infections especially RSV pneumonia (palivazumab, monoclonal antibody prophylaxis for RSV, is currently being considered by NICE).
What is the prognosis of chronic lung disease?
Severely affected infants may require long-term home O2 therapy.
