Oxygen Targets and Home Oxygen in Evolving BPD
A 26-week preterm infant is now 36 weeks postmenstrual age. Birth weight was 780 g; current weight is 2.1 kg. He has been on nasal cannula oxygen at 1 L/min for 3 weeks. Awake SpO2 is 92–94%; during feeds and sleep it drops to 88–90% for 1–2 minutes, resolving when the nurse stimulates him or increases oxygen briefly. He has mild subcostal retractions and a respiratory rate of 55–65/min. He is fed by nasogastric tube and gaining 15 g/day. Chest radiograph shows diffuse hazy opacities. Echocardiogram shows a small patent ductus arteriosus with left-to-right shunt and estimated right ventricular systolic pressure of 35 mmHg (systemic systolic pressure 70 mmHg).
1. What oxygen saturation target would you prescribe, and how would you manage the intermittent desaturations?
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For an infant with evolving bronchopulmonary dysplasia, target SpO2 90–95% awake and during sleep, avoiding sustained values below 90% and unnecessary hyperoxia above 95%. The brief desaturations to 88–90% during feeds and sleep are common but should not be ignored; first optimize feeding (paced feeds, consider fortification, evaluate for aspiration) and ensure the oxygen cannula is secure. If desaturations persist, increase baseline flow or use overnight oximetry to guide home oxygen. Do not aim for 100%; higher saturations increase the risk of retinopathy of prematurity and may worsen ventilation-perfusion matching.
2. What criteria would you use to decide whether this infant can go home on oxygen?
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Discharge on oxygen requires: stable SpO2 above 90% on a low, measurable flow during wake, sleep, and feeds; no recurrent apnea or bradycardia; adequate weight gain (15 g/day is acceptable but should be sustained); parents trained in equipment use, pulse oximetry, and emergency plans; a safe home environment; and close follow-up within 1–2 weeks. A room-air challenge is reasonable only if the infant has been stable for several days. The mild pulmonary hypertension (RVSP 35 mmHg) is a reason to avoid hypoxia and to arrange cardiology follow-up.
3. How do the echocardiogram findings influence your management?
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The estimated RVSP of 35 mmHg with a systemic systolic pressure of 70 mmHg indicates mild pulmonary hypertension, which is common in BPD. Management is to prevent hypoxia, treat the underlying BPD (nutrition, diuretics if fluid overloaded, avoid respiratory infections), and monitor with repeat echocardiography in 4–8 weeks. The small PDA with left-to-right shunt may contribute to pulmonary overcirculation; discuss with cardiology whether closure is indicated if pulmonary hypertension worsens or if the infant cannot wean from oxygen. Oxygen is a pulmonary vasodilator, so maintaining saturations is therapeutic.