title: Left ventricular performance and regional blood flows before and after ductus arteriosus occlusion in premature lambs treated with surfactant.
abstract: The hemodynamic consequences of patent ductus arteriosus (PDA) were studied during the first few hours of life (1.9 +/- 0.7 hours) in 13 mechanically ventilated, surfactant-treated, preterm lambs (gestational age of 120-124 days). Cardiovascular pressures, left ventricular (LV) performance and regional blood flows were measured using cine left ventriculography and radionuclide-labeled microspheres before and after occlusion of the PDA with a catheter balloon. Before occlusion, the left-to-right shunt was 44 +/- 13%; after occlusion the shunt was negligible (2%). Heart rate (164 +/- 17 beats/min), LV end-diastolic pressure (5 +/- 3 mm Hg), ejection fraction (74 +/- 8%) and cardiac output (241 +/- 13 ml . min-1 . kg-1) were normal and did not change after ductus occlusion. However, "effective" systemic blood flow increased significantly after occlusion (130 +/- 53 vs 228 +/- 93 ml . min-1 . kg-1, p less than 0.001), as did blood flow to organs such as the brain, myocardium and gastrointestinal tract. The reduction of systemic blood flow in the presence of a left-to-right PDA shunt may be responsible for many early pathologic manifestations of the PDA "syndrome" of prematurity even in the absence of overt LV dysfunction.
mesh_terms: D000818:Animals; D001775:Blood Circulation; D002302:Cardiac Output; D003326:Coronary Circulation; D004064:Digestive System / Q000098:blood supply; D004374:Ductus Arteriosus, Patent / Q000503:physiopathology / Q000628:therapy*; D011652:Pulmonary Circulation; D011663:Pulmonary Surfactants / Q000627:therapeutic use*; D012039:Regional Blood Flow; D012756:Sheep
chemical_list: D011663:Pulmonary Surfactants