Comparison Of Computed Tomography Quantitative Analysis Versus Single Indicator Thermodilution In Measurements Of Pulmonary Edema In Patients With Acute Respiratory Distress Syndrome

Objective:To measure pulmonary edema by single indicator thermodilution method and computed tomography quantitative analysis in patients with acute lung injury/acute respiratory distress syndrome and compare the two techniques.Method:Ten patients with acute lung injury/acute respiratory distress syndrome; All patients underwent a spiral CT of the thorax, and measured CT-measured gas content of lung (GVCT), lung weight (LWCT), the lung weight index (LWI),the average radiographic attenuation value (CTmean) for the whole lung and the gas to tissue ratio(g/t) through computed tomography quantitative analysis. Then pulmonary thermal volume (PTV) and extravascular lung water index(EVLWI) were determined by PiCCO plus system. These two methods of pulmonary edema measurement were compared. What's more, the correlation coefficients of CT or PiCCO variables with Crs, PaO2/FiO2, APACHEⅡscore and SOFA score were measured.Results:(1)The monitoring indicators values were as follows:LWCT 1221.37±383.68g, LWI 18.12±6.79g/kg, PTV 1498.1±466.45ml, EVLWI 17.5±10.4ml/kg, GVCT 916.58±418.08ml, CTmean -407.97±118.30Hu, g/t 0.80±0.40ml/g; The percentages of lung weights of non-aerated, poorly aerated, normally aerated and hyper-aerated zones were 32.55±9.26%,39.92±13.82%,27.46±9.29%,0.06±0.11% respectively. (2) There was a close positive correlation (r =0.8878;P=0.0006;PTV=1.0793×LWCT+179.8) between PTV and LWCT. A closer positive correlation (r=0.9459;P<0.0001;EVLWI=1.4506×LWI-8.7792) was found between EVLWI and LWI. The bias between LWCT and PTV,LWI and EVLWI were -277±217,0.62±4.56 respectively. (3)Pleural fluid affected the correlations between CT or PiCCO variables. (4)There was no significant correlation between EVLWI and CT distribution of lung tissue compartments. (5)No significant correlations were found between CT or PiCCO variables and Crs, PaO2/FiO2, APACHEⅡscore or SOFA score.Conclusion:Measurements of pulmonary edema by computed tomography quantitative analysis show good correlation and agreement with those by single indicator thermodilution method.