Seear M, Webber S, Leblanc J
Department of Intensive Care, Children's Hospital, Vancouver, Canada.
Pediatr Cardiol. 1994 Jul-Aug;15(4):178-83. doi: 10.1007/BF00800672.
In previous work, we postulated that mean aortic flow velocity (MAFV) might be a direct measure of cardiac index. To investigate the assumptions inherent in this relation, we measured body surface area, aortic cross-sectional area (two-dimensional ultrasonography) and MAFV (Doppler ultrasonography) in 70 normal children. For a direct check of the relation, we simultaneously measured cardiac index (Fick technique) and MAFV (Doppler ultrasonography) in 25 children after cardiac surgery. In the normal group, we found that body surface area was directly proportional to aortic cross-sectional area (R 0.94), and MAFV at rest was the same in the ascending and descending aorta (t test, p < 0.05). In the intensive care patients, MAFV in the descending aorta was directly proportional to cardiac index over a wide clinical range [MAFV (cm/s) = CI (L/min/m2).7.7-1.2]. The assumptions made when deriving the relation between MAFV and cardiac index appear to be valid whether measured in the ascending or descending aorta. However, the scatter of results limits its clinical value. Mean aortic flow velocity is probably of greater use as a trend indicator and has the potential for continuous display using an esophageal Doppler probe when measured in the descending aorta.
在之前的研究中，我们推测平均主动脉流速（MAFV）可能是心指数的直接测量指标。为了研究这种关系中固有的假设，我们对70名正常儿童测量了体表面积、主动脉横截面积（二维超声检查）和MAFV（多普勒超声检查）。为了直接检验这种关系，我们对25名心脏手术后的儿童同时测量了心指数（Fick法）和MAFV（多普勒超声检查）。在正常组中，我们发现体表面积与主动脉横截面积成正比（R = 0.94），升主动脉和降主动脉的静息MAFV相同（t检验，p < 0.05）。在重症监护患者中，降主动脉的MAFV在较宽的临床范围内与心指数成正比[MAFV（cm/s）=心指数（L/min/m²）×7.7 - 1.2]。无论在升主动脉还是降主动脉测量，推导MAFV与心指数之间关系时所做的假设似乎都是有效的。然而，结果的离散性限制了其临床价值。平均主动脉流速作为趋势指标可能更有用，并且当在降主动脉测量时，使用食管多普勒探头有连续显示的潜力。
