Spontaneous breathing with biphasic positive airway pressure attenuates lung injury in hydrochloric acid-induced acute respiratory distress syndrome.
BACKGROUND
It has been proved that spontaneous breathing (SB) with biphasic positive airway pressure (BIPAP) can improve lung aeration in acute respiratory distress syndrome compared with controlled mechanical ventilation. The authors hypothesized that SB with BIPAP would attenuate lung injury in acute respiratory distress syndrome compared with pressure-controlled ventilation.


METHODS
Twenty male New Zealand white rabbits with hydrochloric acid aspiration-induced acute respiratory distress syndrome were randomly ventilated using the BIPAP either with SB (BIPAP plus SB group) or without SB (BIPAP minus SB group) for 5 h. Inspiration pressure was adjusted to maintain the tidal volume at 6 ml/kg. Both groups received the same positive end-expiratory pressure level at 5 cm H2O for hemodynamic goals. Eight healthy animals without ventilatory support served as the control group.


RESULTS
The BIPAP plus SB group presented a lower ratio of dead space ventilation to tidal volume, a lower respiratory rate, and lower minute ventilation. No significant difference in the protein levels of interleukin-6 and interleukin-8 in plasma, bronchoalveolar lavage fluid, and lung tissue were measured between the two experimental groups. However, SB resulted in lower messenger ribonucleic acid levels of interleukin-6 (mean ± SD; 1.8 ± 0.7 vs. 2.6 ± 0.5; P = 0.008) and interleukin-8 (2.2 ± 0.5 vs. 2.9 ± 0.6; P = 0.014) in lung tissues. In addition, lung histopathology revealed less injury in the BIPAP plus SB group (lung injury score, 13.8 ± 4.6 vs. 21.8 ± 5.7; P < 0.05).


CONCLUSIONS
In hydrochloric acid-induced acute respiratory distress syndrome, SB with BIPAP attenuated lung injury and improved respiratory function compared with controlled ventilation with low tidal volume.
From the Department of Intensive Care Medicine, China-Japan Friendship Hospital, Beijing, P. R. China (J.X., Q.Z.); and Beijing Institute of Respiratory Medicine, Department of Respiratory and Critical Care Medicine, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, P. R. China (H.Z., B.S., R.Y., H.H.).
Jingen
J
Xia
Heng
H
Zhang
Bing
B
Sun
Rui
R
Yang
Hangyong
H
He
Qingyuan
Q
Zhan
D000818:Animals; D006851:Hydrochloric Acid / Q000633:toxicity*; D055370:Lung Injury / Q000139:chemically induced / Q000503:physiopathology / Q000517:prevention & control*; D008297:Male; D011175:Positive-Pressure Respiration / Q000379:methods; D011817:Rabbits; D012119:Respiration / Q000187:drug effects; D012128:Respiratory Distress Syndrome / Q000139:chemically induced / Q000503:physiopathology / Q000628:therapy*; D015656:Respiratory Mechanics / Q000187:drug effects / Q000502:physiology*
D006851:Hydrochloric Acid