Bronchopulmonary dysplasia and chronic neonatal lung disease

Question 1 (10 marks)

a) Classify this infant's BPD severity according to the NIH consensus definition. Justify your answer. (3 marks) This infant has severe BPD. The NIH consensus definition classifies severity at 36 weeks postmenstrual age. Severe BPD requires 30 percent or more supplemental oxygen and/or positive pressure ventilation at 36 weeks PMA. This infant is on 32 percent oxygen via nasal cannula, meeting the threshold for severe BPD [1].

b) List four evidence-based interventions that reduce the incidence of BPD in extremely preterm infants. (4 marks) Caffeine citrate (20 mg/kg loading, then 5 to 10 mg/kg daily) reduced BPD from 47 to 36 percent in the CAP trial [2]. Early CPAP strategy was non-inferior to prophylactic surfactant in the SUPPORT trial [3]. Vitamin A supplementation (5000 IU IM three times weekly for four weeks) reduces BPD with NNT of 14 to 20 [2]. Antenatal corticosteroids accelerate fetal lung maturation and reduce RDS severity [3].

c) What is the recommended oxygen saturation target range for preterm infants, and what evidence supports this? (3 marks) The recommended target is SpO₂ of 91 to 95 percent. The Cochrane review found lower targets (85 to 89 percent) increased mortality without reducing retinopathy, leading to adoption of the 91 to 95 percent range [1].

Question 2 (10 marks)

a) This infant develops a loud P2 and hepatomegaly. What complication is suspected, and how is it investigated? (4 marks) The findings suggest pulmonary hypertension, complicating 8 to 25 percent of moderate-to-severe BPD cases and representing the leading cause of late mortality [1]. Investigation requires urgent echocardiography to assess pulmonary artery pressure, right ventricular hypertrophy, septal flattening, and tricuspid regurgitation [1].

b) Outline the pharmacological management of BPD-associated pulmonary hypertension. (3 marks) Management is guided by echocardiography and specialist cardiology. Options include inhaled nitric oxide at 10 to 20 ppm, oral sildenafil at 0.5 to 2 mg/kg per dose three times daily, and bosentan as an endothelin receptor antagonist [1].

c) List four discharge criteria for an infant with BPD requiring home oxygen. (3 marks) First, stable respiratory support and oxygen for at least four weeks with a documented home oxygen plan [1]. Second, adequate weight gain on full oral or safe tube feeds [1]. Third, no significant apnoea for five to seven days off caffeine [1]. Fourth, SpO₂ above 90 percent on prescribed oxygen with parents trained in delivery [1].