Histopathological examination.

<p>Representative appearances and photomicrographs of hematoxylineosin–stained lung sections (magnification ×200) from control group (A, n = 6), BIPAP_SB = biphasic positive airway pressure with SB (B, n = 6), and BIPAP_AP = biphasic positive airway pressure with abdominal muscles paralysis (C, n = 6).The control group had minimal alveolar congestion, and inflammatory cell infiltration. The BIPAP_AP group showed mild thickening of the alveolar walls, alveolar congestion, and hemorrhage. In the BIPAP_SB group, inflammatory cell infiltration, thickening of the alveolar walls, alveolar congestion, and more prominent hemorrhagic areas were observed.