Control of flow of fetal lung fluid at the laryngeal outlet

Adams, Forrest H.; Desilets, Donald T.; Towers, Bernard

doi:10.1016/0034-5687(67)90035-7

Cited by 88 publications

(20 citation statements)

References 4 publications

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“…Thus, high negative intrathoracic pressure, as might be expected at birth, is associated with the removal of liquid from the lung even in the absence of air breathing, and therefore without the consequent changes in Pacoz and Pao,. Similar periods of rapid fall may occur normally, for example when FPF is expelled periodically from the trachea into the posterior pharynx, as has been demonstrated in the intact lamb fetus in situ (1). As in fetus 2, this may be followed by a "recovery" period in which FPF volume increases at a rate that is very much higher than normal.…”

Section: Distribution O F Risasupporting

confidence: 54%

Lamb Fetal Pulmonary Fluid. I. Validation and Significance of Method for Determination of Volume and Volume Change

1975

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ExtractAn indicator-dilution method is described for measuring fetal pulmonary fluid, FPF, volume (Ve), and volume change with time (VS) in the lamb fetus in utero. The indicator, albumin, which is the predominant protein of normal FPF, was administered directly to FPF in the form of radioiodinated human serum albumin (RISA). We have shown that (I) RISA is disbributed homogeneously throughout the FPF compartment, (2) it is not altered within FPF, (3) it does not alter the functional characteristics of FPF, and (4) it remains within the FPF compartment throughout the period of measurement. Ve varies directly with the weight of the fetus so that Ve per kilogram was 31.6-35.6 ml/kg in four of five fetuses. The Ve per kilogram was lower in one fetus at the start of the experiment but increased rapidly to 29.0 ml/kg within 45 min. Thus the relaxation volume of the fetus in utero is in the range of functional residual capacity (FRC) and thoracic gas volume of the air-breathing neonate, which indicates that the pulmonary transformation at birth is, in essence, an isovolumic change in state wherein the fetal liquid-lung becomes the neonatal air-lung. The rate at which FPF is formed (Vs) is about 1.5 ml/hr-kg; however, the rate may change in so far as both rapid increases and rapid decreases of FPF volume were observed. When breathing movements were induced in the fetus by stimulation of the sciatic nerve, FPF volume decreased rapidly (Vs = -3.0 ml/hrkg), which indicates that negative intrathoracic pressures promote its resorption. When FPF volume fell transiently or was low initially, there was subsequent rapid restoration of volume to the range of anticipated FRC.

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Section: Distribution O F Risasupporting

confidence: 54%

Lamb Fetal Pulmonary Fluid. I. Validation and Significance of Method for Determination of Volume and Volume Change

1975

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“…With FPF they are expelled periodically from the lung of the lamb fetus and are swallowed (1). Whether or not they also enter the amniotic fluid compartment and add in a significant way t o its phospholipid content is a moot question which, with regard t o the lamb fetus, has received a negative answer (5).…”

Section: Speculationmentioning

confidence: 99%

“…Lung surfactant activity accompanies increased lecithin biosynthesis in the developing fetus of several species (13, 14, 28), and lung extracts from infants dying of respiratory distress with alveolar hyaline membranes have abnormal surface active properties (1 5, 20). De novo lecithin synthesis in lung tissue of experimental animals occurs by at least two pathways ( 1 ) the formation of phosphorylcholine and its transfer from cytidine diphosphorylcholine (CDPcholine) to 1,2-diacyl-sn-glycerol (DaB-diglyceride) (3, 5, 17, 27), and (2) the trimethylation of ethanolamine phosphoglyceride (7, 14, 19).…”

Section: Speculationmentioning

confidence: 99%

Lamb Fetal Pulmonary Fluid. II. Fate of Phosphatidylcholine

et al. 1975

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“…First, it has been established that the fluid distending fetal lung is produced by the lung and is not amniotic fluid [17]. Measured flow rates (e.g., sheep) show that this fluid issues from lung into the nasopharynx [1] at rates as high as 30-120 ml/hr [34]. These secretions continue after birth.…”

Section: Introductionmentioning

confidence: 99%