thromboxane-b2 and Persistent-Fetal-Circulation-Syndrome

To examine whether neonates with persistent pulmonary hypertension are subject to a thromboxane-mediated exacerbation of their pulmonary hypertension during extracorporeal membrane oxygenator therapy (a form of partial cardiopulmonary bypass), we performed serial measurements of plasma thromboxane B2 and pulmonary artery pressure before, during, and after extracorporeal membrane oxygenation. Pulmonary artery pressure was high before extracorporeal membrane oxygenation, did not increase after the start of this therapy, but began to decrease after 48 hours of extracorporeal membrane oxygenation. During the course of extracorporeal membrane oxygenation, mean pulmonary artery pressure decreased by 50% and mean plasma thromboxane B2 levels decreased by 70%. In addition, serial plasma thromboxane B2 levels were significantly correlated with pulmonary artery pressures in individual infants with a primary diagnosis of meconium aspiration (r = 0.965 to 0.723). We speculate that the decrease in pulmonary artery pressure and plasma thromboxane B2 levels over time may reflect resolution of acute lung injury and that thromboxane B2 may play a role in regulating pulmonary artery pressure in infants with meconium aspiration.

Topics: Echocardiography; Extracorporeal Membrane Oxygenation; Humans; Infant, Newborn; Persistent Fetal Circulation Syndrome; Pulmonary Wedge Pressure; Thromboxane B2; Time Factors

Thromboxane B2 may be a mediator of neonatal persistent pulmonary hypertension. Elevated levels of plasma thromboxane and prostacyclin have been described previously in hypoxic newborn infants with neonatal pulmonary hypertension. We measured serial plasma levels of thromboxane B2 and 6-keto-prostaglandin F1 alpha (stable metabolite of prostacyclin) in 21 newborn infants with severe respiratory failure and pulmonary hypertension who required extracorporeal membrane oxygenation support. We sought to study (1) the evolution of plasma prostanoids in pulmonary hypertensive infants treated with extracorporeal membrane oxygenation and (2) whether different pulmonary hypertensive diagnostic subgroups have distinctive prostanoid profiles. Our data indicated that infants with meconium aspiration had significantly lower levels of plasma thromboxane B2 and 6-keto-prostaglandin F1 alpha while receiving extracorporeal membrane oxygenation than did infants with persistent pulmonary hypertension but no meconium aspiration. Levels of all infants decreased progressively as extracorporeal membrane oxygenation support continued.

Topics: 6-Ketoprostaglandin F1 alpha; Carbon Dioxide; Epoprostenol; Extracorporeal Membrane Oxygenation; Humans; Infant, Newborn; Meconium Aspiration Syndrome; Oxygen; Persistent Fetal Circulation Syndrome; Respiratory Insufficiency; Thromboxane B2

A prospective study of 10 neonates with congenital diaphragmatic hernia and five controls to determine the importance of prostanoid concentrations perioperatively and the relation with persistent pulmonary hypertension (PPH) is reported. In neonates with congenital diaphragmatic hernia postoperative concentrations of the vasoconstrictor thromboxane B2 rose significantly and were higher during episodes of PPH; this rise may provoke PPH and subsequent right to left shunting.

Topics: 6-Ketoprostaglandin F1 alpha; Airway Resistance; Hernia, Diaphragmatic; Hernias, Diaphragmatic, Congenital; Humans; Infant, Newborn; Oxygen; Persistent Fetal Circulation Syndrome; Postoperative Period; Prospective Studies; Respiratory Function Tests; Thromboxane B2

Pulmonary hypertension was generated in 11 newborn piglets, via either infusion of group B beta-hemolytic streptococci (n = 5) or induction of isocapnic hypoxia (n = 6), to study the contributions of thromboxane metabolite thromboxane B2 levels to different types of pulmonary hypertension. After 30 minutes of stable pulmonary hypertension, mean (+/- SD) pulmonary artery pressure increased similarly from 16 +/- 4 to 33 +/- 5 mm Hg (hypoxic), and from 14 +/- 2 to 34 +/- 6 mm Hg (septic). All other measured hemodynamic variables were similar. Despite these hemodynamic similarities, there were significant differences in thromboxane B2 levels. After 60 minutes of pulmonary hypertension, thromboxane B2 levels were 760 +/- 253 pg/mL (hypoxic), and 3103 +/- 1083 pg/mL (septic). These data demonstrate that, while thromboxane appears to be crucial in mediating septic pulmonary hypertension in the piglet, it is not associated with hypoxic pulmonary hypertension, implying that different types of pulmonary hypertension are probably mediated by different biochemical agents.

Topics: Animals; Hemodynamics; Humans; Hypoxia; Infant, Newborn; Oxygen Consumption; Persistent Fetal Circulation Syndrome; Streptococcal Infections; Streptococcus agalactiae; Swine; Thromboxane B2

Production of platelet thromboxane B2, a stable metabolite of thromboxane A2, was measured in seven newborn infants with pulmonary hypertension during the first day of life. Platelet thromboxane B2 production was significantly lower than in 12 healthy controls but did not correlate with simultaneous blood gas values.

Topics: Blood Platelets; Humans; Infant, Newborn; Persistent Fetal Circulation Syndrome; Thromboxane B2