Babies born too early can get a lung problem called **bronchopulmonary dysplasia (BPD)**. Doctors often use drugs called **diuretics** like **furosemide** to help these babies. Diuretics help the body get rid of extra fluid. This study, called **PRIMED**, will see if these drugs really help in the short term and if they should be used for a longer time. In this study, babies will switch between taking furosemide and a fake pill (placebo) to see if they improve. This is called an **N-of-1 trial**. If babies improve with furosemide, they might continue in a longer study to see if they should take the drug for three more months.

• The study will last at least 28 days.
• Babies must be born before 28 weeks, need breathing help, and be in the hospital for 28 days.
• Babies can't join if they have certain health problems or are on some medications.