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. Author manuscript; available in PMC: 2019 Oct 1.
Published in final edited form as: Semin Fetal Neonatal Med. 2018 Apr 17;23(5):340–346. doi: 10.1016/j.siny.2018.04.001

Figure 1: Phases of lung aeration during newborn transition.

Figure 1:

Figure 1:

Figure 1:

Phase 1: The airways are still fluid-filled, and the emphasis is to clear the fetal lung liquid and aerate the lung.

Phase 2: Lung aeration has been achieved and gas exchange is now possible. The air-liquid surface tension is present, and fetal lung liquid (now in the interstitial tissue) increases perialveolar interstitial tissue pressures. The focus of respiratory support is minimizing alveolar collapse and/or reflooding during expiration.

Phase 3: The lungs is aerated and liquid is cleared from the tissue. Ventilation is now focused on gas exchange and metabolic homeostasis.