目的了解锁骨下静脉(SCV)导管误入同侧颈内静脉(IJV)对经肺热稀释(TPTD)测量参数的影响,并对其机制进行初步研究。方法纳入408例需要SCV导管进行TPTD测量的患者。所有患者均行基础状态TPTD测量,包括平均传输时间(MTt)、对数曲线下降时间(DSt)、心排血指数(CI)、全心舒张末容量指数(GEDVI)、血管外肺水指数(EVLWI)。其中,第1组SCV导管位置正确,第2组SCV导管误入同侧IJV,第2组患者在SCV导管重新放置后进行第二轮测量(第3组),第2组和第3组测量的差值分别记为ΔMTt、ΔDSt、ΔGEDVI和ΔEVLWI。结果第2组患者的GEDVI和EVLWI均显著高于第1组(均P<0.001)。多元逻辑回归显示PaO_(2)/FiO_(2)(OR=1.492/10 mm Hg,P<0.001)、GEDVI(OR=1.307/10 mL/m^(–2),P<0.001)和EVLWI(OR=3.05,P<0.001)3个变量与SCV导管误入IJV独立相关。第2组的GEDVI、EVLWI、CI、MTt和DSt均显著高于第3组(SCV导管重新放置后)的相关测量参数(均P<0.001)。多元线性回归显示ΔEVLWI(R^(2)=0.86,P<0.001)与ΔMTt(回归系数–0.52,P<0.001)显著负相关,与ΔDSt(回归系数1.45,P<0.001)显著正相关。结论在SCV导管误入同侧IJV时进行的TPTD测量,CI、GEDVI和EVLWI会被显著高估。DSt的延长是EVLWI被高估的主要因素。由于GEDVI、EVLWI结果的可靠性对于指导液体复苏和做出液体管理相关决策至关重要,一旦怀疑导管位置异常,应立即进行X线检查确认并调整导管位置。
Objective: The subclavian vein (SCV) is usually used to inject the indicator of cold saline for a transpul- monary thermodilution (TPTD) measurement. The SCV catheter being misplaced into the internal jugular (IJV) vein is a common occurrence. The present study explores the influence of a misplaced SCV catheter on TPTD variables. Methods: Thirteen severe acute pancreatitis (SAP) patients with malposition of the SCV catheter were enrolled in this study. TPTD variables including cardiac index (CI), global end-diastolic volume index (GEDVI), intrathoracic blood volume index (ITBVI), and extravascular lung water index (EVLWl) were obtained after injection of cold saline via the misplaced SCV catheter. Then, the misplaced SCV catheter was removed and IJV access was constructed for a further set of TPTD variables. Comparisons were made between the TPTD results measured through the IJV and mis- placed SCV accesses. Results: A total of 104 measurements were made from TPTD curves after injection of cold saline via the IJV and misplaced SCV accesses. Bland-Altman analysis demonstrated an overestimation of +111.40 ml/m2 (limits of agreement: 6.13 and 216.70 ml/m2) for GEDVI and ITBVI after a misplaced SCV injection. There were no significant influences on CI and EVLWI. The biases of +0.17 L/(min.m2) for CI and +0.17 ml/kg for EVLWI were re- vealed by Bland-Altman analysis. Conclusions: The malposition of an SCV catheter does influence the accuracy of TPTD variables, especially GEDVI and ITBVI. The position of the SCV catheter should be confirmed by chest X-ray in order to make good use of the TPTD measurements.