Lung liquid production rates and volumes do not  decrease before labor in healthy fetal sheep

Lines, Andrea; Hooper, Stuart B.; Harding, Richard

doi:10.1152/jappl.1997.82.3.927

Cited by 44 publications

(30 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast, as postural changes during labor can cause lung liquid loss [29], flexion of the fetal trunk, which increases abdominal pressure and elevates the diaphragm, are more likely to cause liquid expulsion [22,23]. …”

Section: Pulmonary Transitionmentioning

confidence: 99%

Measuring Physiological Changes during the Transition to Life after Birth

Vonderen¹,

et al. 2014

View full text Add to dashboard Cite

The transition to life after birth is characterized by major physiological changes in respiratory and hemodynamic function, which are predominantly initiated by breathing at birth and clamping of the umbilical cord. Lung aeration leads to the establishment of functional residual capacity, allowing pulmonary gas exchange to commence. This triggers a significant decrease in pulmonary vascular resistance, consequently increasing pulmonary blood flow and cardiac venous return. Clamping the umbilical cord also contributes to these hemodynamic changes by altering the cardiac preload and increasing peripheral systemic vascular resistance. The resulting changes in systemic and pulmonary circulation influence blood flow through both the oval foramen and ductus arteriosus. This eventually leads to closure of these structures and the separation of the pulmonary and systemic circulations. Most of our knowledge on human neonatal transition is based on human (fetal) data from the 1970s and extrapolation from animal studies. However, there is renewed interest in performing measurements directly at birth. By using less cumbersome techniques (and probably more accurate), our previous understanding of the physiological transition at birth is challenged, as well as the causes and consequences for when this transition fails to progress. This review will provide an overview of physiological measurements of the respiratory and hemodynamic transition at birth. Also, it will give a perspective on some of the upcoming technological advances in physiological measurements of neonatal transition in infants who are unable to make the transition without support.

show abstract

Section: Pulmonary Transitionmentioning

confidence: 99%

Measuring Physiological Changes during the Transition to Life after Birth

Vonderen¹,

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Experiments in the fetal lamb have shown that the lung liquid volume rises until the end of gestation, reaching a level of 50 mL/kg of fetal body weight on the day before labour 22,23 . According to these authors, the entire volume of fetal lung liquid ($250 mL) in ovine fetuses is cleared during normal labour 24 . In contrast to these studies, others have suggested that the volume 25,26 and production rate 27 of fetal lung liquid decrease up to 10 days before the onset of labour.…”

Section: Discussionmentioning

confidence: 99%

Does fetal tracheal fluid flow during fetal breathing movements change before the onset of labour?

Kalache¹,

Chaoui

Marks

et al. 2002

BJOG

View full text Add to dashboard Cite

Objective To examine changes in intra-tracheal fluid flow parameters during fetal breathing movements throughout the second half of pregnancy in the normally developing human fetus. Design Prospective cross-sectional study.Setting Fetal medicine unit at the Charité University Hospital in Berlin.Methods Assessment of tracheal fluid flow was attempted in 340 healthy fetuses (GA 20-40 weeks) in which fetal breathing movements were seen by B-mode scan. Colour Doppler was applied to visualise the tracheal fluid flow, followed by spectral Doppler to record the velocity waveforms. The records of 53 fetuses divided into five gestational age groups (20 -23, 24-27, 28-31, 32 -35 and 36 -40 weeks of gestation) containing 40 or more continuous breathing cycles (inspiration and expiration) were considered for analysis. Only regular breathing phases were examined and the volume obtained by integration of the tracheal fluid flow displaced during fetal breathing movements was calculated. Results The intra-tracheal flow volume moved during inspiration (Vi) and expiration (Ve) increased until 36 weeks of gestation after which there was a flattening until term. This suggests either a reduction of lung liquid production or a diminished lung liquid volume. The median difference between Vi and Ve was positive in the first four age groups and negative in the last one suggesting that, in mature fetuses, the effect of fetal breathing movements no longer results in an influx. Conclusions Our data demonstrate a modification in fetal behaviour that manifests itself during the last four weeks before birth and has the potential to reduce lung liquid volume.

show abstract

“…However, the little resistance that the chest offers when it follows the head through the birth canal makes it unlikely that 'vaginal squeeze' significantly influences liquid clearance [14,15]. Postural changes during labor can cause lung liquid loss [16] and flexion of the fetal trunk during delivery, which causes an increase of abdominal pressure and elevation of the diaphragm, are more likely to cause liquid expulsion [11,13].…”

Section: Pioneers In Pulmonary Imaging At Birthmentioning

confidence: 99%