Airway pressure release ventilation reduces the increase in bronchoalveolar lavage fluid high-mobility group box-1 levels and lung water in experimental acute respiratory distress syndrome induced by lung lavage.
OBJECTIVE
Airway pressure release ventilation (APRV) may provide better alveolar recruitment at a lower peak airway pressure than conventional mechanical ventilation (CMV) and, therefore, decrease the risk of barotrauma in patients with acute lung injury and acute respiratory distress syndrome. The present study compared the effects of APRV with low tidal volume ventilation (LTV) and CMV on the ongoing response in lung injury induced by whole lung lavage.


METHODS
Lung injury was induced by whole lung lavage. Twenty-one Japanese white rabbits were randomized to receive CMV (tidal volume 10 ml kg, positive end-expiratory pressure 3 cmH2O), LTV (tidal volume 6 ml kg, positive end-expiratory pressure 10 cmH2O), or APRV (Phigh 20 cmH2O, Plow 5 cmH2O). After 4 h of treatment, the lungs and heart were excised en bloc. The left lung was lavaged, and high-mobility group box-1 (HMGB1) levels were measured in the lavage. The right lung was analysed histologically and its wet-to-dry weight ratio was calculated.


RESULTS
PaO2 was decreased after the induction of lung injury, but the values were significantly higher in the APRV and LTV groups after treatment than in the CMV group. Serum HMGB1 levels did not change before and after lung injury; however, bronchoalveolar lavage fluid HMGB1 levels were significantly increased at the end of the experiment (266.8 +/- 47.9 in the CMV group, 137.4 +/- 23.4 in the LTV group, and 91.2 +/- 5.4 ng ml in the APRV group). The bronchoalveolar lavage fluid HMGB1 levels after experiment were significantly lower in the APRV group than in the CMV and LTV groups (P < 0.0001 and P = 0.0391, respectively). Wet-to-dry weight ratios were also lowest in the APRV group.


CONCLUSIONS
APRV reduces bronchoalveolar lavage fluid HMGB1 levels and lung water and it preserves oxygenation and systemic blood pressure in experimental acute respiratory distress syndrome. The results suggest that APRV could be as protective for acute respiratory distress syndrome as LTV with positive end-expiratory pressure.
Matsuzawa
Yoshiyasu
Y
Department of Anesthesiology and Critical Care Medicine, Tokyo Medical and Dental University School of Medicine, Bunkyo-ku, Tokyo, Japan.
Nakazawa
Koichi
K
Yamamura
Akio
A
Akashi
Takumi
T
Kitagaki
Keisuke
K
Eishi
Yoshinobu
Y
Makita
Koshi
K
D055371:Acute Lung Injury / Q000209:etiology / Q000378:metabolism / Q000517:prevention & control*; D000818:Animals; D018893:Bronchoalveolar Lavage / Q000009:adverse effects*; D001992:Bronchoalveolar Lavage Fluid; D045422:Continuous Positive Airway Pressure / Q000379:methods*; D015633:Extravascular Lung Water / Q000378:metabolism; D024243:HMGB1 Protein / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011817:Rabbits; D011897:Random Allocation; D012128:Respiratory Distress Syndrome / Q000209:etiology / Q000378:metabolism / Q000517:prevention & control*; D013990:Tidal Volume / Q000502:physiology
D024243:HMGB1 Protein