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Query: UMLS:C0020440 (hypercapnia)
 7,939 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. In chronically catheterized sheep fetuses, during normal pregnancy, the concentration of PGE in the fetal femoral arterial plasma is invariably greater than that of PGF, and increases during the 12 to 24 hr preceding delivery. The concentration of both PGE and PGF decreases repidly after birth. 2. These changes in fetal prostaglandin levels contrast with the marked increase in PGF, but negligible increase in PGE, in the maternal uteroovarian vein before parturition. 3. The changes in prostaglandin concentrations in fetal plasma at term are associated with only small changes in the concentrations of PGE and PGF in tracheal fluid. In amniotic fluid the concentrations of PGE and PGF increase during the last 4 days in utero. At birth the concentrations of PGE and PGF in fetal urine are similar to the concentrations in amniotic fluid. 4. The concentration of PGE in fetal plasma and in tracheal fluid is significantly elevated for up to 3 days after surgery. The concentration of PGF is significantly elevated in fetal plasma nad tracheal fluid for at least 24 hr after surgery. 5. Three fetuses which were chronically hypoxemic had elevated plasma PGE concentrations in utero. However, acute (1 hr) hypoxia or hypercapnia induced in the fetal lamb by making the ewe breathe appropriate gas mixtures did not produce consistent changes in fetal plasma prostaglandin concentrations. 6. During late pregnancy (day 128) exogenous PGE2 infused at about 1.6 microgram/min for 60 min into the fetal carotid artery achieved concentrations in the fetal femoral artery which were within the physiological range seen at term. At this infusion rate, there was no effect on fetal arterial Po2, Pco2, pH, or hematocrit, and no consistent effect on fetal blood pressure or heart rate. PGE2 infusion had no significant effect on the concentration of growth hormone or prolactin in fetal plasma. Within 30 min after beginning the infusion, however, there was a significant increase in the cortisol concentration in fetal plasma. This effect was seen even at times in pregnancy when the fetal adrenal gland responds only poorly to exogenous or endogenous ACTH.
Adv Prostaglandin Thromboxane Res 1978
PMID:Prostaglandins in the sheep fetus: implications for fetal function. 64 1

Persistent pulmonary hypertension of the newborn (PPHN), initially described by Gersony et al as persistent foetal circulation (PFC syndrome), results from a flawed transition from foetal to extrauterine pulmonary circulation. It is characterised by the maintenance of a high pulmonary vascular resistance and right-to-left shunting through the ductus arteriosus and foramen ovale. Infants with a wide variety of underlying clinical conditions develop PPHN. According to Rudolph three main anatomic types of PPHN can be identified: normal pulmonary vascular development increased pulmonary vascular smooth muscle development decreased cross-sectional area of pulmonary vascular bed. It is important to realize that several pathophysiologic mechanisms may coexist and interact. Besides metabolic and respiratory acidosis, hypercapnia and hypoxaemia some other factors induce pulmonary vasoconstriction. Thromboxane, leukotrienes and prostaglandins play a decisive role. Since PPHN can be associated with a broad spectrum of clinical conditions, a specific clinical picture is lacking. The baby is usually term or post-term, cyanotic immediately after birth or some hours later. Birth asphyxia, hyperviscosity, sepsis and aspiration of meconium have been recognized as predisposing factors. The diagnosis can be confirmed by echocardiography. Contrast echo will indicate right-to-left shunting with normal anatomy. Currently hyperventilation, tolazolin, chlorpromazin and dopamine/dobutamine have been advocated as central foci for clinical therapy. Recently prostacyclin was introduced as a specific pulmonary vasodilatator.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Persistent pulmonary hypertension of newborn. The PFC syndrome]. 229 36