摘要
目的：分别应用CT定量分析法和单指示剂经肺热稀释法定量评价急性呼吸窘迫综合征患者肺水肿程度,并比较二者的相关性和一致性。
方法：收集10例因治疗需要进行胸部CT检查及PiCCO plus监测的急性肺损伤／急性呼吸窘迫综合征患者,运用CT定量分析法计算全肺平均CT值(CTmean)、气体容积(GVCr)、组织重量(LWCT)及组织重量指数(LWICT)、气体-组织比(g/t)。在行CT检查的同日应用PiCCO plus系统通过单指示剂经肺热稀释法获得每位患者的胸腔内热容积(PTV)及血管外肺水指数(EVLWI)。并收集氧合指数(PaO2/FiO2)、呼吸系统顺应性(Crs)、APACHEⅡ评分及SOFA评分。通过直线回归分析探讨两种方法对肺水肿程度定量评价的相关性,用Bland-Altman's plots法评价PTV与LWCT、EVLWI与LWICT的一致性,并研究Crs、PaO2/FiO2、APACHEⅡ评分、SOFA评分与以上肺水肿定量指标之间是否具有相关性。
结果：(1)LWCT和LWI分别为1221.37±383.68g和18.12±6.79g/kg；PTV为1498.1±466.45ml, EVLWI为17.5±10.4ml/kg。CT定量分析法测定GVCT、CTmean和g/t分别为916.58±418.08ml、-407.97±118.30Hu和0.80±0.40ml/g；肺部不通气区、通气减低区、正常通气区及过度通气区肺组织重量的百分比分别为32.55±9.26%、39.92±13.82%、27.46±9.29%、0.06±0.11%。(2)LWCT与PTV之间有着显著的正相关性(r=0.8878；P=0.0006；PTV=1.0793×LWCT+179.8)。LWI与EVLWI之间也呈显著正相关性,且相关性优于LWCT与PTV(r=0.9459；P<0.0001；EVLWI=1.4506×LWI-8.7792)。LWCT与PTV之间差值的95%可信区间为-701.64～148.26,LWI与EVLWI之间差值的95%可信区间为-8.32～9.55,90%(9/10)的患者LWCT与PTV之差、LWI与EVLWI之差位于其95%可信区间内。(3)有大量胸水组及无大量胸水组PTV与LWCT的相关系数分别为0.39和0.9 (P=0.034); EVLWI与LWI的相关系数分别为0.62和0.97(P=0.0035)。(4)EVLWI与过度通气区、正常通气区、通气减低区及不通气区肺组织重量百分比之间均无显著地相关性。(5) PaO2/FiO2、Crs、APACHEⅡ评分及SOFA评分与CTmean、GVCT、LWI、g/t、PTV、EVLWI等指标之间均无显著的相关性。
结论：CT定量分析法与单指示剂经肺热稀释法对急性呼吸窘迫综合征肺水肿的定量测定有着良好的相关性和一致性。
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.
引文
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