[A comparison study on quantitative methods for the recruited volume in sheep with acute respiratory distress syndrome].
OBJECTIVE
To compare equal pressure method with pressure-volume curve method to quantify the recruited volume.


METHODS
Acute respiratory distress syndrome sheep model was induced by intravenous infusion 3 microg/kg lipopolysaccharide (LPS). Recruited volume of three different levels of positive end-expiratory pressure (PEEP=5, 10, 15 cm H2O) were measured both by pressure-volume curve method and by equal pressure method.


RESULTS
The time needed to measure recruited volume by pressure-volume curve method was 5-6 minutes, which was longer than that of equal pressure method. Recruited volume measured by the two methods increased with PEEP. No significant difference was found between the recruited volume measured by equal pressure method and by equal pressure method at PEEP of 5 cm H2O, they were (25.79+/-20.48) ml vs. (63.26+/-54.57) ml (P>0.05), while recruited volume at PEEP of 10 cm H2O and 15 cm H2O measured by equal pressure method were lower than those measured by the pressure-volume curve method, they were (48.64+/-30.51)ml vs. (148.14+/-85.42)ml and (71.50+/-58.09)ml vs. (322.86+/-148.42)ml (all P<0.05) respectively.


CONCLUSIONS
Though equal pressure method is simple, it could not take the place of pressure-volume curve method to quantify recruited volume.
Xu
Hong-yang
HY
Department of Critical Care Medicine, Zhongda Hospital and School of Clinical Medicine, Southeast University, Nanjing 210009, Jiangsu, China.
Qiu
Hai-bo
HB
Yang
Yi
Y
Zhou
Shao-xia
SX
Sun
Hui-ming
HM
Chen
Yong-ming
YM
D000818:Animals; D004195:Disease Models, Animal; D008176:Lung Volume Measurements / Q000379:methods*; D008297:Male; D011175:Positive-Pressure Respiration; D012128:Respiratory Distress Syndrome / Q000503:physiopathology / Q000628:therapy*; D012756:Sheep