儿童心脏功能评估在儿童重症领域之应用

由于心脏的解剖结构与血管系统息息相关,因此心脏的功能,其实也就是心血管的功能,或者就是所谓的循环系统的功能,其实也就是血流力学的功能状态.综合言之,都可以用心血管功能或循环功能代表.在儿科重症监护室中的心脏功能评估相关应用以能快速实用为主,与一般心脏科的范畴稍有差异.准此原则,心脏功能的评估,包括基本评估以及进阶评估两大类.所谓基本评估,就是只用临床上非使用仪器的方法来做的较单纯的评估,也就是身体检查.身体检查可以侦测到肝脏肿大,外周水肿或者颈静脉怒张,心脏搏动点的位置等诸多身体的异常征象以及微血管充盈时间等,以显示心脏循环的功能以及血流力学的功能状态.至于进阶的心功能评估包括非侵袭性的方法以及侵袭性的方法.非侵袭性的方法,最常用的就是心脏超声检查,经过心脏的超声检查,可以观测心脏的收缩状态以及舒张状态,心包膜积水等,是临床上最常使用的床边检查工具.另外四腔电阻抗心电图近年来也常被用来评估心脏的输出量.侵袭性的方法通常是使用一些导管,例如(1)动脉导管:动脉血压的波形及数值.(2)中枢静脉导管:可以监测右心房的压力.(3)肺动脉楔压导管:可以监测肺动脉楔压等同于肺动脉微血管压力,或者雷同于左心房填充压,这是左心室功能的重要指标.(4)脉搏容积导管监测(PiCCO):近似于肺动脉楔压,但是可以提供更广泛的指标,除了心输出量之外还可以包括肺部水含量、胸腔液的含量等.总而言之,心脏功能/循环功能/血流力学监测等其实本身包含非常复杂的生理病理观念以及参数运算.在重症监护室的医疗人员,未必需要了解所有的细节,但是至少必须要对于一些较单纯的参数,能够在患者床边检测参数,有一些基本的了解,并且做适当的运用,才能够使危重症患者得到最好的照顾.

Evaluation of cardiac function in pediatric intensive care unit

Cardiac function is closely related to circulatory function,and both terms can be integrated together as" hemodynamics". Thus the author will use the collective term"hemodynamic evaluation" rather than "cardiac function". There are several ways to evaluate hemodynamic status. Briefly,we can use physical examination as clinical indices of hemodynamics. The physical examination method can detect cardiac impulse position,liver size, peripheral edema, distension of jugular vein to identify circulatory dysfunction. Besides relative simple basic method,there are other means to detect circulatory function. We usually divided them into 2 categories:invasive versus non-invasive means. The non-invasive means include echocardiography and impedance electrocardiography. Echocardiography can provide portable, easily operated platform to evaluate classical cardiac function including fractional shortening,cardiac wall thickness,pressure gradient evaluation and ejection fraction(EF). The impedance electrocardiography can provide continuous index for circulatory functional evaluation. The invasive means include arterial pressure wave analysis, central venous pressure monitoring,floating catheter for capillary wedge pressure monitoring and cardiac output. The relatively newer device includes pressure index countour cardiac output( PiCCO) method,using similar but simple not only to derive cardiac output,but also lung water and other complex indices. In summary,hemodynamic evaluation of circulatory functional status is rather complex, a thorough understanding of ongoing pathophysiology is of prime importance. All clinicians working in the intensive card unit should carefully select the most appropriate ones according to the accessibility and familiarity and mechanism of operation.