严重创伤患者颈内静脉截面积及呼吸变异与中心静脉压的关系

Correlation between sizes and respiratory variation of internal jugular veins and central venous pressure in severe trauma patients

目的了解严重创伤患者颈内静脉截面积及呼吸变异与中心静脉压的关系，为临床应用床旁超声快速评估严重创伤患者的血容量提供依据。方法对急诊监护室收治的50例严重创伤患者，在完全控制通气下以超声测定双侧颈内静脉于吸气末和呼气末的最大和最小截面积，计算静脉的呼吸变异指数。同时记录患者脱开呼吸机时的中心静脉压及机械通气的气道压力。并与27例正常人比较颈内静脉截面积的大小，观察静脉截面积的大小、呼吸变异指数与中心静脉压的相关性，确定预测中心静脉压的最佳指标和相应的阈值。结果严重创伤患者的颈内静脉截面积较对照组明显增大，中心静脉压与颈内静脉截面积的大小、呼吸变异指数存在相关性。调整机械通气的影响，右侧颈内静脉最小截面积、左侧颈内静脉的呼吸变异指数预测中心静脉压〉12cmH2O具有较好的价值，相应的阈值分别为1．37cm^2（敏感性84．6％，特异性66．7％）和10．8％（敏感性66．7％，特异性84．6％）。结论应用超声测定颈内静脉截面积的大小及呼吸变异指数能在一定程度上预测中心静脉压水平，是评估严重创伤患者血容量的可选方法。

Objective To explore the correlation between sizes and respiratory variation of internal jugular veins （IJV） and central venous pressure （CVP）,and to provide proof for rapid evaluation of blood volume with ultrasonography in severe trauma patients. Methods Sizes of IJV at the end of inspiration and respiration were determined by uhrasonography in 50 patients with controlled ventilation, who were with severe trauma and admitted to emergency intensive care unit. Respiratory variation index of IJV （RVI） were calculated as following： RVI = （size at inspiratory end- size at respiratory end）/size at respiratory end × 100%. Central venous pressure with ventilator off and airway pressure were also recorded. Sizes of IJV were compared with those of 27 healthy volunteers. Correlation between sizes and respiratory variation index of IJV and CVP were evaluated, then the optimal parameters to estimate CVP and the corresponding threshold were determined. Results Sizes of IJV in severe trauma patients were larger than those in control group. There were correlations between sizes and respiratory variation index of IJV and CVP. After adjusted by affection of mechanical ventilation,size of right IJ V at respiratory end and RVI of left IJV were regarded as the optimal parameters to estimate CVP over 12 cmH2O. The corresponding thresholds were 1.37 cm^2 （with sensitivity of 84.6% and specificity of 66.7%） and 10.8% （with sensitivity of 66.7 % and specificity of 84.6%）, respectively. Conclusions Size and respiratory variation of internal jugular veins determined with clinician-performed uhrasonography could estimate central venous pressure at a certain extent,which may be an alternative method to evaluate blood volume in severe trauma patients.