[Evaluation of the characteristic of alveolar recruitment and derecruitment with the static pressure-volume curve in rabbits with acute respiratory distress syndrome].
OBJECTIVE
To evaluate the value of static pressure-volume (P-V) curve during alveolar recruitment and derecruitment in mechanical ventilated rabbits with acute respiratory distress syndrome (ARDS), and to explore the lung protective ventilation strategies.


METHODS
The ARDS rabbit model was duplicated by warm-saline alveolar lavage. Dynamic CT scan was implemented to monitor the intrapulmonary gas volume and distribution during alveolar recruitment and derecruitment gradually. Static P-V curve was measured to reflect the features of alveolar recruitment and derecruitment.


RESULTS
Four aeration regions including nonaeration, insufficient aeration, normal aeration and overinflation regions, varied following airway pressure variation (t = 2.477 - 9.794, all P < 0.05). Recruitment of insufficient aeration region was found. Alveolar recruitment was divided two parts, alveolar open at nonaeration region and recruitment at insufficient aeration region. And alveolar derecruitment was divided two parts, alveolar close at nonaeration region and derecruitment at insufficient aeration region. Distribution frequency of alveolar open was different from inspiratory (r = 0.219, P = 0.220). And distribution frequency of alveolar close was different from expiratory (r = 0.094, P = 0.593). The compliance of P-V curve was only positively correlated with the volume of insufficient aeration region (inspiration r = 0.827, P = 0.006; expiration r = 0.792, P = 0.011). The airway pressure with the maximal compliance at inspiratory P-V curve [(16.2 +/- 3.5) cm H2O, 1 cm H2O = 0.098 kPa] was positively correlated with the alveolar opening pressure [(16.4 +/- 3.4) cm H2O, r = 0.900, P = 0.002], and the airway pressure with the maximal compliance at expiratory P-V curve [(11.9 +/- 2.4) cm H2O] was positively correlated with the alveolar closing pressure [(11.3 +/- 2.5) cm H2O, r = 0.887, P = 0.003].


CONCLUSIONS
During inspiration, alveolar recruitment takes place with alveolar overinflation. The compliance of P-V curve is correlated with insufficient region volume, and reflects the potential of lung recruitment, and can predict the alveolar opening pressure and closing pressure.
Long
Yun
Y
Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China.
Liu
Da-wei
DW
Jin
Zheng-yu
ZY
Chai
Wen-zhao
WZ
Liu
Hong-zhong
HZ
Wang
Xiao-ting
XT
D000818:Animals; D008168:Lung / Q000000981:diagnostic imaging* / Q000473:pathology; D008449:Maximal Expiratory Flow-Volume Curves; D011312:Pressure; D011650:Pulmonary Alveoli / Q000000981:diagnostic imaging* / Q000473:pathology; D011817:Rabbits; D012128:Respiratory Distress Syndrome / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology*; D014057:Tomography, X-Ray Computed