Cariou A, Monchi M, Joly L M, Bellenfant F, Claessens Y E, Thébert D, Brunet F, Dhainaut J F
Medical Intensive Care Unit, Cochin-Port Royal University Hospital, Paris, France.
Crit Care Med. 1998 Dec;26(12):2066-72. doi: 10.1097/00003246-199812000-00043.
The Sometec Dynemo-3000 system allows the permanent measurement of descending aorta diameter by an echographic (A-scan) device and the blood flow velocity by a pulse Doppler velocimeter. The Dynemo-3000 then furnishes a new hemodynamic parameter, i.e., descending aortic blood flow (ABF), which is a fraction of the cardiac output (CO). We evaluate the ability of this system to measure the aortic diameter and to accurately detect ABF changes.
A case study prospective trial.
A 24-bed medical intensive care unit of a 1,100-bed university hospital.
Twenty critically ill patients fully sedated, mechanically ventilated, and monitored by a pulmonary artery catheter.
CO values determined by conventional thermodilution method (TD-CO) and ABF were recorded during the study, which included two initial baseline periods, a dobutamine infusion (5 microg/kg/min) interval of 30 mins, and a third baseline period. To assess the accuracy of A-scan, aortic diameter was measured by transesophageal echocardiography. The difference between echocardiography and A-scan was used to determine bias and precision for aortic diameter measurements. TD-CO and ABF variations were analyzed using Kruskal-Wallis and Wilcoxon tests. Association between TD-CO and ABF values was determined by calculating the linear correlation coefficient. The ability of ABF to detect a TD-CO >6.0 L/min and its variations >13% was analyzed by determination of sensitivity, specificity, and positive (PPV) and negative (NPV) predictive values.
Aortic diameter measurements by A-scan and bidimensional methods were 23.0+/-2.8 mm (SD) and 24.2+/-2.7 mm, respectively. Bias and precision were 1.1 mm and 1.4 mm (95% confidence interval: -1.9 to 3.7), respectively. During the course of dobutamine infusion, we observed a significant increase of TD-CO mean value from 6.65+/-1.53 L/min to 9.30+/-2.5 L/min (p=.0008), and a parallel and significant increase in ABF mean value from 4.34+/-1.18 L/min to 5.70+/-1.63 L/min (p= .0029). Absolute TD-CO and ABF values had a correlation coefficient of 0.80. For detection of an increased TD-CO, PPV and NPV were 87% and 86%, respectively. For detection of TD-CO changes >13%, PPV and NPV were 80% and 94%, respectively.
The Dynemo-3000 system is able to display the real aortic diameter, which is one of the most important components of this noninvasive ultrasonic technique. When compared with TD-CO, the ABF determination provided by this ultrasonic device constitutes a reliable noninvasive tool for estimating CO and tracking its changes.
Sometec Dynemo - 3000系统可通过超声（A扫描）设备对降主动脉直径进行连续测量，并通过脉冲多普勒测速仪测量血流速度。然后，Dynemo - 3000可提供一个新的血流动力学参数，即降主动脉血流量（ABF），它是心输出量（CO）的一部分。我们评估该系统测量主动脉直径以及准确检测ABF变化的能力。
一项病例研究前瞻性试验。
一家拥有1100张床位的大学医院的24张床位的医疗重症监护病房。
20例重症患者，均处于深度镇静状态，接受机械通气，并通过肺动脉导管进行监测。
在研究过程中记录通过传统热稀释法（TD - CO）测定的CO值和ABF，研究包括两个初始基线期、一个持续30分钟的多巴酚丁胺输注（5微克/千克/分钟）期以及第三个基线期。为评估A扫描的准确性，通过经食管超声心动图测量主动脉直径。超声心动图与A扫描之间的差异用于确定主动脉直径测量的偏差和精密度。使用Kruskal - Wallis和Wilcoxon检验分析TD - CO和ABF的变化。通过计算线性相关系数确定TD - CO和ABF值之间的关联。通过确定敏感性、特异性以及阳性（PPV）和阴性（NPV）预测值，分析ABF检测TD - CO > 6.0升/分钟及其变化> 13%的能力。
通过A扫描和二维方法测量的主动脉直径分别为23.0±2.8毫米（标准差）和24.2±2.7毫米。偏差和精密度分别为1.1毫米和1.4毫米（95%置信区间：-1.9至3.7）。在多巴酚丁胺输注过程中，我们观察到TD - CO平均值从6.65±1.53升/分钟显著增加至9.30±2.5升/分钟（p = 0.0008），同时ABF平均值从4.34±1.18升/分钟平行且显著增加至5.70±1.63升/分钟（p = 0.0029）。绝对TD - CO和ABF值的相关系数为0.80。对于检测TD - CO升高，PPV和NPV分别为87%和86%。对于检测TD - CO变化> 13%，PPV和NPV分别为80%和94%。
Dynemo - 3000系统能够显示真实的主动脉直径，这是这种无创超声技术最重要的组成部分之一。与TD - CO相比，该超声设备提供的ABF测定是一种可靠的无创工具，用于估计CO并跟踪其变化。
