Inspiration regulates the rate and temporal pattern of lung liquid clearance and lung aeration at birth

Melissa Li-Lian Siew, Megan Jane Wallace, Marcus John Kitchen, Robert A Lewis, Andreas Fouras, Arjan B Te Pas, Naoto Yagi, Kentaro Uesugi, Karen Kit Wan Siu, Stuart Brian Hooper

Research output: Contribution to journalArticleResearchpeer-review

Abstract

At birth, the initiation of pulmonary gas exchange is dependent on air entry into the lungs and recent evidence indicates that pressures generated by inspiration may be involved. We have used simultaneous plethysmography and phase contrast X-ray imaging to investigate the contribution of inspiration and expiratory braking maneuvers (EBMs) to lung aeration and the formation of a functional residual capacity (FRC) after birth. Near term rabbit pups (n=26) were delivered by caesarean section, placed in a water plethysmograph and imaged during the initiation of spontaneous breathing. Breath-by-breath changes in lung gas volumes were measured using plethysmography and visualized using phase contrast X-ray imaging. Pups rapidly (1-5 breaths) generate a FRC (16.2+/-1.2ml/kg) by inhaling a greater volume than they expire (by 2.9+/-0.4 mL/kg/breath over first 5 breaths). As a result, 94.8+/-1.4 of lung aeration occurred during inspiration over multiple breaths. The incidence of EBMs were rare early during lung aeration, with most (>80 ) occurring after >80 of max FRC was achieved. Although EBMs were associated with an overall increase in FRC, 34.8+/-5.3 of EBMs were associated with a decrease in FRC. We conclude that lung aeration is predominantly achieved by inspiratory efforts and that EBMs help to maintain FRC, following its formation. Key words: lung liquid clearance, fetus, expiratory braking maneuvers.
Original languageEnglish
Pages (from-to)1888 - 1895
Number of pages8
JournalJournal of Applied Physiology
Volume106
Issue number6
DOIs
Publication statusPublished - 2009

Cite this

Siew, Melissa Li-Lian ; Wallace, Megan Jane ; Kitchen, Marcus John ; Lewis, Robert A ; Fouras, Andreas ; Te Pas, Arjan B ; Yagi, Naoto ; Uesugi, Kentaro ; Siu, Karen Kit Wan ; Hooper, Stuart Brian. / Inspiration regulates the rate and temporal pattern of lung liquid clearance and lung aeration at birth. In: Journal of Applied Physiology. 2009 ; Vol. 106, No. 6. pp. 1888 - 1895.
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abstract = "At birth, the initiation of pulmonary gas exchange is dependent on air entry into the lungs and recent evidence indicates that pressures generated by inspiration may be involved. We have used simultaneous plethysmography and phase contrast X-ray imaging to investigate the contribution of inspiration and expiratory braking maneuvers (EBMs) to lung aeration and the formation of a functional residual capacity (FRC) after birth. Near term rabbit pups (n=26) were delivered by caesarean section, placed in a water plethysmograph and imaged during the initiation of spontaneous breathing. Breath-by-breath changes in lung gas volumes were measured using plethysmography and visualized using phase contrast X-ray imaging. Pups rapidly (1-5 breaths) generate a FRC (16.2+/-1.2ml/kg) by inhaling a greater volume than they expire (by 2.9+/-0.4 mL/kg/breath over first 5 breaths). As a result, 94.8+/-1.4 of lung aeration occurred during inspiration over multiple breaths. The incidence of EBMs were rare early during lung aeration, with most (>80 ) occurring after >80 of max FRC was achieved. Although EBMs were associated with an overall increase in FRC, 34.8+/-5.3 of EBMs were associated with a decrease in FRC. We conclude that lung aeration is predominantly achieved by inspiratory efforts and that EBMs help to maintain FRC, following its formation. Key words: lung liquid clearance, fetus, expiratory braking maneuvers.",
author = "Siew, {Melissa Li-Lian} and Wallace, {Megan Jane} and Kitchen, {Marcus John} and Lewis, {Robert A} and Andreas Fouras and {Te Pas}, {Arjan B} and Naoto Yagi and Kentaro Uesugi and Siu, {Karen Kit Wan} and Hooper, {Stuart Brian}",
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Inspiration regulates the rate and temporal pattern of lung liquid clearance and lung aeration at birth. / Siew, Melissa Li-Lian; Wallace, Megan Jane; Kitchen, Marcus John; Lewis, Robert A; Fouras, Andreas; Te Pas, Arjan B; Yagi, Naoto; Uesugi, Kentaro; Siu, Karen Kit Wan; Hooper, Stuart Brian.

In: Journal of Applied Physiology, Vol. 106, No. 6, 2009, p. 1888 - 1895.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Inspiration regulates the rate and temporal pattern of lung liquid clearance and lung aeration at birth

AU - Siew, Melissa Li-Lian

AU - Wallace, Megan Jane

AU - Kitchen, Marcus John

AU - Lewis, Robert A

AU - Fouras, Andreas

AU - Te Pas, Arjan B

AU - Yagi, Naoto

AU - Uesugi, Kentaro

AU - Siu, Karen Kit Wan

AU - Hooper, Stuart Brian

PY - 2009

Y1 - 2009

N2 - At birth, the initiation of pulmonary gas exchange is dependent on air entry into the lungs and recent evidence indicates that pressures generated by inspiration may be involved. We have used simultaneous plethysmography and phase contrast X-ray imaging to investigate the contribution of inspiration and expiratory braking maneuvers (EBMs) to lung aeration and the formation of a functional residual capacity (FRC) after birth. Near term rabbit pups (n=26) were delivered by caesarean section, placed in a water plethysmograph and imaged during the initiation of spontaneous breathing. Breath-by-breath changes in lung gas volumes were measured using plethysmography and visualized using phase contrast X-ray imaging. Pups rapidly (1-5 breaths) generate a FRC (16.2+/-1.2ml/kg) by inhaling a greater volume than they expire (by 2.9+/-0.4 mL/kg/breath over first 5 breaths). As a result, 94.8+/-1.4 of lung aeration occurred during inspiration over multiple breaths. The incidence of EBMs were rare early during lung aeration, with most (>80 ) occurring after >80 of max FRC was achieved. Although EBMs were associated with an overall increase in FRC, 34.8+/-5.3 of EBMs were associated with a decrease in FRC. We conclude that lung aeration is predominantly achieved by inspiratory efforts and that EBMs help to maintain FRC, following its formation. Key words: lung liquid clearance, fetus, expiratory braking maneuvers.

AB - At birth, the initiation of pulmonary gas exchange is dependent on air entry into the lungs and recent evidence indicates that pressures generated by inspiration may be involved. We have used simultaneous plethysmography and phase contrast X-ray imaging to investigate the contribution of inspiration and expiratory braking maneuvers (EBMs) to lung aeration and the formation of a functional residual capacity (FRC) after birth. Near term rabbit pups (n=26) were delivered by caesarean section, placed in a water plethysmograph and imaged during the initiation of spontaneous breathing. Breath-by-breath changes in lung gas volumes were measured using plethysmography and visualized using phase contrast X-ray imaging. Pups rapidly (1-5 breaths) generate a FRC (16.2+/-1.2ml/kg) by inhaling a greater volume than they expire (by 2.9+/-0.4 mL/kg/breath over first 5 breaths). As a result, 94.8+/-1.4 of lung aeration occurred during inspiration over multiple breaths. The incidence of EBMs were rare early during lung aeration, with most (>80 ) occurring after >80 of max FRC was achieved. Although EBMs were associated with an overall increase in FRC, 34.8+/-5.3 of EBMs were associated with a decrease in FRC. We conclude that lung aeration is predominantly achieved by inspiratory efforts and that EBMs help to maintain FRC, following its formation. Key words: lung liquid clearance, fetus, expiratory braking maneuvers.

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JO - Journal of Applied Physiology

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SN - 8750-7587

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