Hemodynamic changes during weaning: can we assess and predict cardiac-related weaning failure by transthoracic echocardiography?

Cardiac-related failure of weaning from mechanical ventilation is an important reason for prolonged mechanical ventilation, intensive care unit treatment, and increased morbidity and mortality. When transthoracic echocardiography (TTE) is routinely performed before a weaning trial, patients at high risk of cardiac-related failure can be detected by low left ventricular (LV) ejection fraction, diastolic dysfunction, and elevated LV filling pressure. During the weaning trial, a further increase of LV filling pressure and progression of diastolic failure can be observed by repeated TTE. Owing to certain limitations concerning patients and methodology, TTE cannot be employed in every patient and invasive hemodynamic monitoring is still mandatory in selected patients with repetitive weaning failure.     

Echocardiography: a help in the weaning process

Introduction  

To evaluate the ability of transthoracic echocardiography (TTE) to detect the effects of spontaneous breathing trial (SBT) on central hemodynamics and to identify indices predictive of cardiac-related weaning failure.     

左室舒张性心力衰竭的左心形态及舒张功能的超声评价

目的探讨左室舒张性心力衰竭(LVDHF)的左心形态及舒张功能的超声心动图特点。方法 LVDHF组60例,健康体检30例为对照组,超声心动图测量左房内径(LAD)、左室内径(LVD)、舒张期室间隔厚度(IVST)、左室后壁厚度(LVPWT)、左室射血分数(LVEF)、二尖瓣口舒张早期流速峰值(E)、肺静脉反向血流速度(Ar)、彩色M型血流传播速度(Vp)、二尖瓣瓣环舒张早晚期速度比(Ea/Aa)、E/Ea及心室收缩期与舒张期正向波峰速比(S/D)。结果与对照组比较,LVDHF组LAD、IVST、LVPWT、E/Ea及Ar均增加,Ea/Aa、Vp及S/D均减小,差异均有统计学意义(P<0.05)。结论超声心动图能正确判断左室舒张功能,是目前临床通用的诊断左室舒张性心力衰竭的最佳办法。     

急性左心衰患者肺部超声影像变化及其临床意义

目的通过观察肺部超声影像(LUS)在急性左心衰患者中的变化,评价LUS在急性左心衰诊断及鉴别诊断中的意义。方法随机选取88例急性呼吸困难患者,根据其病因分为急性左心衰组(A组)和非急性左心衰组(B组)。对两组患者行肺部超声检查计算肺部超声彗星尾征(ULCs)数目,超声心动图测量EF值、E/Ea值,并测定静脉血N末端B型钠尿肽原(NT-proBNP)。比较两组患者ULCs数目、EF值、E/Ea值和NT-proBNP的差别,以及ULCs数目与EF值、E/Ea值以及NT-proBNP之间的相关性。结果 A组ULCs中位数(21 vs.3)、NT-proBNP中位数(3785 pg/ml vs.412 pg/ml)以及E/Ea(12.05±3.38 vs.6.65±2.23)明显高于B组(P<0.05);A组EF(0.35±0.07 vs.0.58±0.04)明显低于B组(P<0.05)。ULCs数目与NT-proBNP水平(r=0.396,P<0.05)和E/Ea值(r=0.460,P<0.05)呈正相关,与EF值负相关(r=-0.713,P<0.05)。结论急性左心衰患者LUS可见明显ULCs,急性左心衰程度越重,ULCs数目越多。LUS有助于早期判断急性左心衰严重程度,并有助于与其他疾病所致急性呼吸困难相鉴别。     

膈肌超声联合超声心动图预测ICU机械通气患者脱机结果的价值

目的探讨膈肌超声联合超声心动图在重症机械通气患者脱机中的价值。 方法筛选2019年6月至2020年6月间入住山西医科大学第一医院ICU并进行机械通气的56例准备脱机拔管的患者。满足脱机条件后，进行30 min自主呼吸试验（SBT），在SBT期间进行膈肌活动度（DE）及超声心动图的检查。根据脱机结果分为脱机成功组和脱机失败组。将单因素分析中有统计学意义的变量纳入多因素Logistic回归模型中探讨结局的独立影响因素，绘制受试者工作特征曲线（ROC），并结合曲线下面积（AUC）进行统计分析。 结果56例患者中有15例患者脱机失败，DE的ROC的AUC为0.797，截断值≤12.4 mm诊断准确率最高，其敏感度为88%，特异度为67%；E/e'的ROC的AUC为0.787，以11.9为截断值具有最佳的敏感度与特异度（95%，67%）。DE值越大，E/e'越小，脱机成功率越高。二者联合的ROC的AUC为0.886，灵敏度为83%，特异度为87%。 结论DE及E/e'可作为预测脱机结局的临床指标，将二者联合可提高对脱机失败的预测价值。     

经胸超声心动图对3种兔心力衰竭模型的检测

目的应用经胸超声心动图评价兔3种不同类型心力衰竭模型的效果。方法24只兔随机分成3组,A组急性心肌梗死组,结扎冠状动脉左前降支致前间壁心肌梗死;B组扩张型心肌病组,阿霉素经耳缘静脉给药复制扩心病模型;C组慢性压力后负荷心肌肥厚组,主动脉缩窄法制作心肌肥厚致心力衰竭模型。术后不同时间行心脏超声检查评价造模效果。结果经胸超声可获取兔心脏清晰图像。A组造模成功表现为节段性室壁运动异常和射血分数(EF)减低。B组左心扩大,心功能显著下降,并可出现心包积液。C组先出现心肌肥厚,EF增高,终末期心腔扩大,EF下降。结论应用超声心动图技术活体检测兔心力衰竭模型效果可行。     

超声心动图根据主动脉瓣和/或二尖瓣反流压差评估左心腔压力价值的探讨

目的采用血浆脑钠素(BNP)和二尖瓣血流频谱舒张早期速度与二尖瓣环组织多普勒舒张早期速度比值(E/Ea)等指标作参照,探讨超声心动图根据主动脉瓣和二尖瓣反流压差评估左心腔压力的临床实用价值。方法研究对象为118例超声心动图存在轻度二尖瓣反流和/或主动脉瓣反流患者(GTOTAL)。其中31例测定了BNP(GBNP),余87例未检测BNP(NGBNP)。常规超声心动图检查记录射血分数(EF),左心房前后径(LAD),常规检测右上肢肱动脉血压(收缩压,Ps;舒张压,Pd)、主动脉瓣反流频谱舒张末期速度(VAR)、二尖瓣反流频谱最大速度(VMR)。根据公式计算:左心室舒张末期压力(LVEDP)=Ps-4VAR2;左心房压力(LAP)=Ps-4VMR2。分析各组BNP、E/Ea、EF以及LAD与LAP和LVEDP的相关性。结果方差齐性检验和一致性检验显示各组间患者分布状态无显著差异(P>0.05)。各组LAP与BNP、E/Ea、LAD和EF均呈中度相关;各组LVEDP与BNP、E/Ea、LAD和EF的相关性差。结论利用二尖瓣反流测算LAP有一定实用价值。但利用主动脉瓣反流测算LVEDP不能客观反映患者的病理生理状态。     

超声心动图联合钠尿肽前体评价胸部肿瘤患者放疗后左心功能早期损伤

目的 探讨N端B型钠尿肽前体(NT-pro-BNP)联合超声心动图在评价胸部肿瘤患者放疗后左心功能早期损伤的价值.方法 对21例接受胸部全程放疗的胸部肿瘤患者,于放疗前1天、放疗后1天、1个月进行NT-pro-BNP和超声心动图检查,以组织多普勒获取二尖瓣环收缩期峰值速度(Sa)、舒张早期峰值速度(Ea)和舒张晚期峰值速度(Aa)及Ea/Aa、二尖瓣舒张早期血流传播速度(Vp).常规超声心动图指标包括二尖瓣舒张早期峰值流速(E)、心房收缩期峰值流速(A)和E峰减速时间(DT),左心室舒张末期内径、左心房内径、射血分数(EF)和短轴缩短率(FS),同时计算E/Vp和E/Ea.结果 与放疗前相比,放疗后1天NT-pro-BNP明显升高(P＜0.05),放疗后1个月无明显变化(P＞0.05).放疗后Sa、Ea、Vp减低,Aa、E/Vp和E/Ea均升高;常规超声指标放疗前、后无明显变化(P均＞0.05).结论 胸部肿瘤患者接受放疗后,NT-pro-BNP有一定程度升高;组织多普勒、Vp、E/Vp和E/Ea可为早期左心功能损伤评价提供有价值的信息.     

床旁多脏器联合超声在重症患者机械通气脱机风险评估中的应用价值

目的探讨床旁多脏器超声在重症患者机械通气脱机风险评估中的应用价值。 方法选取2016年3月至2017年9月于杭州市第一人民医院及杭州市老年病医院重症医学科进行机械通气治疗、且已达到临床脱机标准的患者72例。所有患者均行床旁多脏器联合超声检查。心脏超声评估心脏大小结构及心功能指标,肺部超声探查双侧胸腔及肺脏,了解肺部情况并进行评分,膈肌超声检查测量膈肌的活动度、厚度及增厚率。对患者的超声检查结果、脱机失败病因及随访预后情况进行分析。 结果72例机械通气患者中,脱机成功46例,脱机失败26例。脱机成功组与脱机失败组比较,2组间左室射血分数（LVEF）、二尖瓣口充盈血流频谱E峰与二尖瓣环组织多普勒e峰比值（E/e′）、主动脉瓣口速度时间积分（AOVTI）、肺动脉收缩压、肺部评分、膈肌增厚率及膈肌活动度差异均有统计学意义（t/Z=0.65、0.63、-4.05、2.03、8.32、11.06、3.58,P均<0.05）。应用多脏器联合超声对脱机失败患者进行随访观察,其中3例膈肌功能障碍患者,通过康复训练,膈肌活动度及增厚率明显提高;3例肺动脉高压患者进行肺动脉压力及肺部超声随访,其中1例动脉导管封堵术后第2天成功脱机。 讨论床旁多脏器联合超声可在患者治疗期间进行实时监测和随访,为机械通气患者脱机的风险评估提供参考依据,具有重要的临床应用价值。     

Impact of milrinone on mitral annular velocity in patients with congestive heart failure

Purpose

The purpose of this study is to assess the impact of milrinone on mitral annular velocity in patients with congestive heart failure.

Method

We studied 27 patients with congestive heart failure. All patients underwent transthoracic echocardiography both before and after administration of milrinone. We measured the early transmitral velocity (E) and the mitral annular early diastolic velocity (Ea). The ratio of E to Ea (E/Ea) was calculated. After the baseline echocardiography, milrinone was administered as a continuous infusion at a rate of 0.25 μg/kg/min. Echocardiographic measurements were repeated 4 h after milrinone was begun.

Results

After administration of milrinone, Ea was significantly increased, while E/Ea was significantly decreased. The population of 27 patients was divided into 20 (74 %) with left ventricular ejection fraction (LVEF) <50 % and seven (26 %) with LVEF ≥50 %. Ea was significantly increased in both groups, while E/Ea was significantly decreased.

Conclusion

Even low-dose milrinone produced an improvement in left ventricular (LV) diastolic function, as evidenced by an increase in Ea, and falls in LV filling pressures, as determined by a decrease in E/Ea, in patients with congestive heart failure throughout a wide range of LV systolic function.     

Impact of a hemodialysis session on cardiac function in patients with chronic renal failure

AIM: To determine the impact of hemodialysis (HD) session on cardiac function in patients with chronic renal failure. MATERIAL AND METHODS: Thirty patients (17 male, 13 female, mean age 49 +/- 11 years) on bicarbonate HD were studied. M-mode echocardiography was performed and ejection fraction (EF) was estimated. Transmitral flow was assessed by Doppler echocardiography. Peak velocity of early (E) and late (A) filling, E/A ratio, isovolumic relaxation time (IVRT) and early deceleration time (DT) were estimated. All the estimations were made one hour before and immediately after HD by one investigator. Flow propagation velocity of early diastolic flow was assessed by color M-mode Doppler echocardiography. RESULTS: A significant decrease of the ejection fraction (delta EF) was observed only in patients with intradialytic hypotension. Hemodialysis resulted in a decrease of early flow velocity from 99.2 +/- 23.8 to 80.6 + 26.0 cm/s (p = 0.0000) and E/A ratio from 1.23 +/- 0.57 to 0.98 +/- 0.43 (p = 0.006). IVRT and DT showed no significant difference. There was a significant positive correlation between the amount of ultrafiltration and deltaE (r = 0.46; p = 0.01), there was no correlation between the amount of ultrafiltration and delta Vp (r = -0.01; p = 0.9). CONCLUSION: The results show that a hemodialysis session influences cardiac function in patients with chronic renal failure. Early diastolic filling considerably decreased in correlation with ultrafiltration. A significant decrease in an ejection fraction was detected only in patients with intradialytic hypotension. Ultrafiltration had no impact on flow propagation velocity of early diastolic flow of the left ventricle assessed by color M-mode Doppler echocardiography.     

心脏超声在高血压左心室肥厚伴左心力衰竭患者中的诊断价值

目的探讨心脏超声在高血压左心室肥厚伴左心力衰竭患者中的诊断价值。方法选择2017年2月至2019年2月我院收治的50例高血压左心室肥厚伴左心力衰竭患者为研究组,另选取同期来院接受常规体检的健康自愿者50例为对照组。两组均接受心脏超声检查。比较两组的心脏功能指标、心脏变异率指标以及研究组不同心功能分级患者的心脏功能指标。结果研究组的左室舒张末期内径(LVEDD)、左室收缩末期内径(LVESD)、二尖瓣舒张期最大血流速度与二尖瓣环舒张早期最大运动速度的比值(E/Ea)均高于对照组,左室射血分数(LVEF)低于对照组(P<0.05)。研究组的全部窦性心搏R-R间期的标准差(SDNN)、相邻R-R间期差值均方根(RMSSD)、相邻窦性R-R间期差值50 ms所占百分比(PNN50)均低于对照组(P<0.05)。随着心功能分级水平的升高,患者的LVEDD、LVESD、E/Ea均升高,而LVEF降低,不同心功能分级患者间比较,差异有统计学意义(P<0.05);心功能Ⅱ、Ⅲ级患者的LVEDD、LVESD、E/Ea均高于心功能Ⅰ级患者,LVEF均低于心功能Ⅰ级患者(P<0.05)。结论结合高血压左心室肥厚伴左心力衰竭患者的疾病特点,应用心脏超声检查方法有助于临床诊断病情,评估患者心功能状态,从而为临床治疗方案的制定提供有效参考依据,值得临床推广应用。     

Elusive left ventricular thrombus: Diagnostic role of cardiac magnetic resonance imaging-A case report and review of the literature

Identification of left ventricular mural thrombus (LVT) may be challenging depending on the imaging modality used. We present a case of LVT which was incidentally identified on cine cardiac magnetic resonance imaging (CMR). A sixty-four years old female presented with worsening dyspnea on exertion with troponin elevation. Transthoracic echocardiography (TTE) revealed a dilated left ventricle (LV) and ejection fraction (EF 30%) with thinning and akinesis of inferior/inferolateral wall was noted with basal and mid inferior wall aneurysm, and thrombus was not identified. CMR done to ascertain viability of myocardium revealed a mural thrombus within basal inferior aneurysm. This was not visualized on transthoracic echocardiography with and without use of contrast. She underwent coronary artery bypass grafting, bioprosthetic mitral valve replacement, resection and plication of posterior left ventricular aneurysm with removal of mural thrombus, and was started on anticoagulation with warfarin post-operatively for the apical thrombi. Cardiac magnetic resonance is a well suited imaging modality in detecting LVT due to its high resolution images and is more reproducible than TTE. In our patient, conventional TTE despite administration of echo-contrast agents failed to diagnose the presence of LVT in the basal inferior aneurysm as well as the apical thrombi. Delayed-enhancement CMR provides the greatest sensitivity for detection of left ventricular thrombus, superior to standard transthoracic and contrast-enhanced transthoracic echocardiography.     

组织多普勒显像对肾上腹主动脉缩窄大鼠心脏形态及舒张功能的研究

目的 采用组织多普勒显像(TDI)评价Lewis大鼠肾上腹主动脉缩窄后心脏的舒张功能变化.方法 选取30只8周龄雄性Lewis大鼠,缩窄其肾上腹主动脉至0.8 mm,造成左室心肌肥厚模型,分别于腹主动脉缩窄术前和术后10 d、20 d、30 d、40 d进行二尖瓣环组织多普勒频谱和常规超声的测量.结果 大鼠心脏前后壁厚度随着随访时间的延长而增加,左室舒张末和收缩末内径也随之增大,左室射血分数(EF)及短轴缩短率(FS)呈下降趋势,以上指标差异均有统计学意义(P＜0.01),大鼠心脏表现为离心性肥厚.二尖瓣环TDI收缩期峰值(Sa)变化趋势不明显,并与EF值相关性较差(r=0.216,P=0.071).无论舒张早期峰值(Ea)、舒张晚期峰值(Aa)和Ea/Aa指标在随访中均无稳定的变化趋势,差异无统计学意义(P＞0.05).而唯有E/Ea一直呈上升趋势,并且经重复测量方差分析,差异有统计学意义(P＜0.001).结论 Lewis肾上腹主动脉缩窄大鼠心脏变化特点主要表现为离心性肥厚,E/Ea值能敏感、稳定地反映大鼠舒张功能的变化过程.     

心源性休克患者静脉-动脉体外膜肺氧合脱机结局影响因素

目的 探讨心源性休克患者静脉-动脉体外膜肺氧合（V-A ECMO）脱机结局的影响因素。方法 回顾性观察37例接受V-A ECMO辅助心源性休克患者，根据是否耐受脱机试验分为可耐受组及不耐受组；再据最终是否成功脱机将可耐受组患者分为成功脱机亚组（脱机且30天内存活）及脱机失败亚组，比较2亚组患者相关资料，以及脱机试验过程中最低流量水平下2亚组超声测得血流动力学参数。结果 37例中，32例可耐受脱机试验（可耐受组），5例无法耐受（不耐受组）。可耐受组患者年龄（P=0.04）及ECMO辅助中出血率（P<0.01）均低于不耐受组，2组患者性别、原发疾病等差异均无统计学意义（P均>0.05）。可耐受组32例中，22例成功脱机，7例脱机失败，3例死亡。脱机试验中最低流量水平下，脱机成功亚组静脉血氧饱和度（SvO₂）、左心室流出道速度-时间积分（LVOT-VTI）、左心室射血分数（LVEF）及二尖瓣环侧壁收缩期运动速度（Sa）均高于脱机失败亚组（P均<0.05）。结论 SvO₂、LVOT-VTI、LVEF及Sa均为V-A ECMO辅助心源性休克患者脱机结局的影响因素。     

血浆N-末端脑钠肽前体对射血分数正常心力衰竭患者诊断价值

目的探讨射血分数正常的心力衰竭患者血浆N-末端脑钠肽前体的水平。方法 30例射血分数正常的心力衰竭患者(观察组)与30例体检健康者(对照组)均行超声心动图检查,检测并比较2组血浆N-末端脑钠肽前体水平。结果观察组血浆N-末端脑钠肽前体水平明显高于对照组(P<0.01);血浆N-末端脑钠肽前体水平与心脏彩超指标舒张早期二尖瓣环运动速度(r=-0.395,P<0.01)、舒张早期二尖瓣环运动速度/舒张晚期二尖瓣环运动速度(r=-0.292,P<0.05)、舒张早期二尖瓣血流速度/舒张早期二尖瓣环运动速度(r=-0.529,P<0.01)呈负相关,与左心房内径(r=0.300,P<0.05)及左心室后壁厚度(r=0.262,P<0.05)呈正相关;血浆N-末端脑钠肽前体水平与舒张功能分级、NYHA分级明显相关(P<0.01);N-末端脑钠肽前体诊断射血分数正常心力衰竭的AUC为0.702,最佳诊断界值127.58pg/mL,此时灵敏度为63.3%,特异度为83.3%。结论血浆N-末端脑钠肽前体对诊断左室射血分数正常的心力衰竭及评价心力衰竭严重程度有重要价值。     

比较组织多普勒、左心房容积对射血分数正常心力衰竭的诊断价值

目的 比较组织多普勒及左心房容积对左心室射血分数正常的心力衰竭的诊断价值,评价这两种超声诊断方法的临床意义.方法 按照中国心力衰竭协会舒张性心力衰竭简化标准,选择左心室射血分数正常（EF≥50％）且血清B型尿钠肽（BNP）≥200 pg/ml的心力衰竭患者30例（HFNEF组）,正常对照组病例（排除心肺疾病）32例,应用超声心动图测量二尖瓣舒张早期血流速度峰值（E峰）、舒张晚期血流速度峰值（A峰）;组织多普勒测量二尖瓣环运动舒张早期速度峰值（E＇峰）、舒张晚期速度峰值（A＇峰）,分别计算E/A比值、E＇/A＇及E/E＇比值;分别测量左心房长轴的直径、左心房的上下径、左右径,计算左心房容积（LAV）.结果 HFNEF组E/A比值1.12±0.58、E＇/A＇比值0.63±0.31,对照组E/A比值1.01 ±0.41、E＇/A＇比值0.63±0.22,两组比较差异无统计学意义（P＞0.05）;E/E’比值HFNEF组为16.05 ±5.19、对照组为10.78±2.07,两组比较差异有统计学意义（P＜0.001）,LAV在HFNEF组为（55.83±13.67） cm3、对照组为（38.11±10.68）cm3,两组之间比较差异有统计学意义（P＜0.001）.E/E＇比值、LAV两者的诊断准确度均为中等偏高;E/E＇在截断点为12.93时,灵敏度为0.65,特异度为0.91,LAV在截断点39.12 cm3水平时,灵敏度为0.95,特异度为0.73.结论 E/E＇比值、LAV超声诊断结合临床症状、体征及生化学指标对于诊断射血分数正常的心力衰竭有较高的准确度和可信度.     

The subxiphoid view cannot replace the apical view for transthoracic echocardiographic assessment of hemodynamic status

Introduction

This prospective study aimed to assess whether use of the subxiphoid acoustic window in transthoracic echocardiography (TTE) can be an accurate alternative in the absence of an apical view to assess hemodynamic parameters.

Methods

This prospective study took place in a teaching hospital medical ICU. Over a 4-month period, TTE was performed in patients admitted for more than 24 hours. Two operators rated the quality of parasternal, apical, and subxiphoid acoustic windows as Excellent, Good, Acceptable, Poor, or No image. In the subpopulation presenting adequate (rated as acceptable or higher) apical and subxiphoid views, we compared the left ventricular ejection fraction (LVEF), the ratio between right and left ventricular end-diastolic areas (RVEDA/LVEDA), the ratio between early and late mitral inflow on pulsed Doppler (E/A ratio), the aortic velocity time integral (Ao VTI), and the ratio between early mitral inflow and displacement of the mitral annulus on tissue Doppler imaging (E/Ea ratio).

Results

An adequate apical view was obtained in 80%, and an adequate subxiphoid view was obtained in 63% of the 107 patients included. Only 5% of patients presented an adequate subxiphoid view without an adequate apical view. In the subpopulation of patients with adequate apical and subxiphoid windows (n = 65), LVEF, E/A, and RVEDA/LVEDA were comparable on both views, and were strongly correlated (r > 0.80) with acceptable biases and precision. However, the Ao VTI and the E/Ea ratio were lower on the subxiphoid view than on the apical view (18 ± 5 versus 16 ± 5 cm and 9.6 ± 4.6 versus 7.6 ± 4 cm, respectively, P = 0.001 for both).

Conclusions

An adequate TTE subxiphoid window was obtained in fewer than two thirds of ICU patients. In addition to the classic indication for the subxiphoid window to study the vena cava and pericardium, this view can be used to study right and left ventricular morphology and function, but does not provide accurate hemodynamic Doppler information. ICU echocardiographers should therefore record both apical and subxiphoid views to assess comprehensively the cardiac function and hemodynamic status.     

多普勒组织成像鉴别陈旧性心肌梗死患者舒张功能假性正常

目的 探讨应用多普勒组织成像（DTI）检测二尖瓣环舒张期运动速度可否鉴别陈旧性心肌梗死（OMI）患者舒张功能假性正常。 方法 OMI舒张功能假性正常患者68例，正常对照组50例，应用脉冲多普勒（PWD）分别测量二尖瓣口舒张早期峰值流速（E）、舒张晚期峰值流速（A）、E／A、E峰减速时间（DT）、左室等容舒张时间（IRT）、肺静脉收缩波（S）、舒张波（D）、S／D及心房收缩波（Ar）；转换DTI速度模式，测量左室侧壁缘二尖瓣环舒张早期运动峰值速度（Ea）、舒张晚期运动峰值速度（Aa）并计算Ea／Aa。 结果 OMI舒张功能假性正常患者与正常人的年龄和血流频谱E、A、E／A、IRT、D、S／D及二尖瓣环Aa测值比较无显著性差异（P〉0.05），DT缩短和S波降低具有显著性差异（P〈0．05），肺静脉血流Ar较正常人升高，而二尖瓣环Ea及Ea／Aa较比正常人明显减低，具有显著性差异（P〈0．01）。 结论 DTI检测二尖瓣环Ea及Ea／Aa比值可鉴别OMI患者舒张功能假性正常。     

血红蛋白浓度变化对机械通气患者脱机结果的预测价值

目的探讨机械通气患者脱机前血红蛋白浓度变化对其脱机结果的预测价值。方法335例机械通气患者用压力支持（PSV）模式进行自主呼吸试验（SBT）。分别在SBT前后测定血红蛋白浓度,用受试者工作特征曲线（ROC）评价血红蛋白变化对脱机结果的预测价值。结果脱机成功组247例,失败组88例。SBT前两组患者基础特征和血红蛋白浓度差异无统计学意义,SBT前后成功组患者血红蛋白浓度变化小于失败组,以血红蛋白浓度变化预测脱机结果的临界值为8．3％,敏感性为85．6％,特异性为80．8％,ROC曲线下面积为0．831。结论SBT前血红蛋白浓度变化可以预测机械通气患者的脱机结果。