Addition of Acetaminophen in Standard PDA Management

Inclusion Criteria: * Infants 23 0/7 to 27 6/7 weeks' gestational age and birth weight \< 1000 grams * Hemodynamically significant PDA as defined by any of the following: 1. Increased ventilator or oxygen support attributed by the clinician to be due to increased left-right shunting through the PDA 2. Hypotension and/or widening pulse pressure requiring continuous dopamine infusion (hypotension is defined as mean arterial pressure (MAP) at least 2-3 mmHg below the infants' post menstrual age) 3. Signs of congestive heart failure (e.g increased pulmonary congestion on chest radiograph or hepatomegaly on physical examination) * Echocardiographic criteria: 1. Ratio of the smallest ductal diameter to the ostium of the left pulmonary artery \> 0.5 Exclusion Criteria: * No enteral feedings * PDA-dependent congenital heart disease * Prior treatment with prophylactic indomethacin * Prior PDA treatment with any medications * Suspected or diagnosed acute necrotizing enterocolitis (NEC) or spontaneous intestinal perforation * Abnormal liver enzymes (ALT \> 60 IU/L and AST \> 60 IU/L) * Platelets count \< 50,000 /μl; and / or active intracranial, gastrointestinal, or other bleeding * Major congenital anomalies such as neural tube defect, known or suspected chromosomal abnormality, and gastrointestinal defect * Prior enrollment to other interventional clinical study where PDA is an outcome variable