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Normothermic Negative Pressure Ventilation Ex Situ Lung Perfusion: Evaluation of Lung Function and Metabolism
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Ventilation/perfusion mismatch during lung aeration at birth
Justin A R Lang1, James T Pearson2, Arjan B te Pas3
1The Ritchie Centre, MIMR-PHI Institute of Medical Research, Melbourne, Australia; Department of Obstetrics and Gynaecology, Monash University, Melbourne, Australia;
Journal of Applied Physiology (Bethesda, Md. : 1985)
|July 5, 2014
Summary
Newborns experience a surge in pulmonary blood flow (PBF) at birth, independent of lung aeration. This study reveals a significant ventilation/perfusion mismatch, challenging existing theories on PBF regulation during this critical transition.
Area of Science:
- Neonatal Physiology
- Cardiopulmonary Development
- Respiratory Medicine
Background:
- Transition to neonatal life involves lung aeration and increased pulmonary blood flow (PBF).
- Existing theories propose PBF increase is spatially linked to ventilated lung regions post-birth.
Purpose of the Study:
- To investigate the spatial relationship between lung aeration and the increase in PBF after birth.
- To determine if PBF is directly correlated with ventilated lung regions in newborns.
Main Methods:
- Simultaneous phase-contrast X-ray imaging and angiography in six near-term rabbits.
- Iodine injection before and after unilateral and bilateral lung ventilation.
- Analysis of iodine distribution in pulmonary arteries (PAs) and heart rate.
Main Results:
- Unilateral ventilation increased PBF to both lungs, not just the ventilated one.
- Pulmonary arteries (PAs) and heart rate significantly increased.
- No spatial difference in PBF was observed between ventilated and non-ventilated lung regions.
Conclusions:
- The increase in PBF at birth is not spatially related to lung aeration.
- A significant ventilation/perfusion mismatch occurs in partially aerated lungs at birth.
- Pulmonary shunting may be present in the early neonatal period.
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