【摘要】  目的 探讨呼吸困难患者的血浆脑利钠肽(BNP)水平与呼吸困难病因之间的相关性及临床意义。 方法　153例呼吸困难的患者分为三组：A组肺源性呼吸困难组51例；B组术后循环血量过多引发呼吸困难组46例； C组心肌收缩力障碍引发呼吸困难组56例，检测其血浆BNP水平和超声心动图检查左室射血分数(LVEF)，部分患者行漂浮导管监测血流动力学。 结果　153例呼吸困难患者的血浆BNP水平和左室射血分数(LVEF)分别是: A组为（178.25 ±45.43） pg/L、（0.61±0.07）pg/L； B组为（3545.58 ±1147.48）pg/L、（0.59±0.06）pg/L； C组为（10471.55 ±3599.23）pg/L、（0.32±0.11）pg/L。C组病人的血浆BNP浓度显著高于B及A组；而B组与A组EF值无明显差别，血浆BNP浓度A组较B组显著增高。结论　BNP的释放直接与心室容量负荷过度和心室收缩力障碍相关，心室收缩力障碍似乎更能够引起血浆BNP水平升高。

【关键词】  心力衰竭；呼吸困难；循环血量；脑利钠肽；血流动力学

　　Abstract:Objective To determine the correlation between the blood level of B?natriuretic peptide (BNP ) and hemodynamic alterations ,and evaluate the diagnostic value of BNP in patients with dyspnea due to different causes. Methods　BNP levels were obtained by a rapid immunofluorescence assay in 153 patients with dyspnea, which were divided into three groups, first group for lung disease (51 patients), second for overload of circulatory blood volume (46 patients), and another for cardiogenic group (56 patients). Hemodynamic parameters of all patients were determined, and left ventricular end diastolic diameters (LVEDD) were measured with echocardiogram. Results　Pulmonary capillary wedge pressure ( PCWP, mm Hg) was (8.20 ±2.60) in the first group, (11.50 ±3.72) in the second group and (30.43 ±7.61) in the last group. Central venous pressure (CVP, mm Hg) of three groups were (6.50±1.90),( 20.95±4.11) and (15.27 ±4.96) respectively. BNP ( pg/L) levels were (178.25 ±45.43), (3545.58 ±1147.48), and (10471.55 ±3599.23) respectively, and left ventricular ejection fraction(LVEF) were (0.59±0.06), (0.61±0.07), and (0.32±0.11). BNP level (918148 ±453125) pg/L of the group with LVEDD  ≥60 mm was much higher than that of the group with LVEDD < 60 mm (298158 ±167151) pg/L ,which was lowest in pulmonary diseases group with a normal left and right ventricular end diastolic diameter  (3514 ±2614) pg/L. There was a great difference of BNP between cardiogenic dyspnea group (761130 ±480147) pg/L  and pulmonary disease group  ( 3514 ±2614) pg/L . Conclusions　Being a kind of cardiac neurohormone secreted from cardiac ventricles as a response to ventricular volume expansion and pressure overload, BNP had a significant increased level in patients with high PCWP.

　　Key words:heart failure；dyspnea；natriuretic peptide；hemodynamics

　　脑利钠肽(BNP)是含32个氨基酸的多肽，刺激BNP分泌的条件主要是心室负荷及室壁张力的改变。本研究对2005年4月至2006年3月在本院中心ICU住院以呼吸困难为主诉的153例重症患者均经干式快速免疫荧光法定量分析检测BNP和超声心动图检查左室射血分数(LVEF)，其中82例患者行血流动力学检查, 探讨呼吸困难患者的血浆脑利钠肽(BNP) 的水平及临床意义。

　　1  资料与方法

　　1.1  分组  ① A组：肺源性呼吸困难组51例,其中男36例,女15例,平均年龄(70.5 ±8.9)岁。其中慢性阻塞性肺病12例、重症肺炎5例、重症支气管哮喘15例、急性肺损伤11例、ARDS 8例。② B组：术后循环血量过多引发呼吸困难组46例 ，其中男33例,女13例,年龄（70.8 ±6.2)岁，排除既往有心脏病史、超声心动图检查左室射血分数(LVEF)<0.49的患者。③C组：心肌收缩力障碍引发呼吸困难组（心肌梗死及心肌炎患者）, 其中男31例,女25例,年龄19 ～85 ( 60.8 ±15.2)岁，其中冠心病急性心肌梗死48例,急性心肌炎8例，NYHA心功能Ⅲ级12例, Ⅳ级44例。心衰诊断参照Framingham标准。排除病例:肝肾功能衰竭、内分泌疾病、气胸、心包填塞、心脏瓣膜疾病、肥厚性心肌病、扩张性心肌病、肺心病。

　　1.2  方法 以呼吸困难为主诉且呼吸频率＞25次/min,伴辅助呼吸肌参与的患者153例常规问诊、体格检查、心电图、胸部X线、超声心动图及同时测定血浆BNP水平。82例患者行漂浮导管检查，穿刺锁骨下静脉，插入漂浮导管至肺动脉分支，测定休息时肺毛细血管嵌压(PCWP)和中心静脉压(CVP)。肺源性呼吸困难组经超声心动图检查无左、右心室增大，左室射血分数(LVEF)>0.49。心衰诊断依据Framingham标准，综合心脏超声等影像学和肺毛细血管嵌压(PCWP)等实验室检查以及病程中对治疗的反应等作出诊断，心功能分级按照美国心脏病协会NYHA 分级方法。BNP浓度测定采用美国Boisite公司Triage干式快速定量诊断仪,采集静脉全血2 mL加入EDTA 抗凝试管,摇匀,取250 μL EDTA抗凝全血加入