Department of Critical Care Medicine, Intensive Care Unit, CABA, Sanatorio De los Arcos, Juan B. Justo 909, Buenos Aires, Argentina.
Argentinian Critical Care Ultrasonography Association (ASARUC), Buenos Aires, Argentina.
J Ultrasound. 2023 Jun;26(2):429-434. doi: 10.1007/s40477-022-00671-6. Epub 2022 Apr 21.
The velocity time integral (VTI) of the left ventricular outflow tract (LVOT) obtained in the apical view by echocardiography can be regarded as a surrogate for the stroke volume. In critically ill patients it is often difficult to obtain an appropriate apical view to assess the VTI. The subcostal view is more accessible, but while it allows a qualitative assessment of the heart, is not adequate for estimating a reliable LVOT VTI, given the inappropriate angle between the Doppler signal and the flow through the LVOT. We present a new modified subcostal view that allows a proper LVOT VTI measurement.
This is a single-centre experimental, retrospective, and observational study using data from patients in a tertiary-care centre. We included adult patients admitted to the intensive care unit in the period from June 2020 to January 2022, who were evaluated by echocardiography and whose LVOT VTI was measured aligned with the Doppler signal in both the apical five-chamber view and the modified subcostal view.
A total of 30 patients were evaluated in the study period by ultrasonography. The Bland-Altman method analysis of the LVOT VTI measured in the apical view compared with that obtained in the subcostal view showed a bias of 0.8 (95% CI 0.39-1.21) with a 95% limit of agreement between - 1.35 (95% CI - 2.06 to - 0.64) and 2.96 (95% CI 2.25-3.67). The percentage error was calculated to be 23%. The Pearson correlation coefficient for the two forms of measurements showed an R value of 0.98 (95% CI 0.96-0.99).
The LVOT VTI measured in a modified subcostal view is useful for estimating the value of the LVOT VTI obtained in an apical view.
通过超声心动图获得的左心室流出道（LVOT）心尖观速度时间积分（VTI）可作为心搏量的替代指标。在危重病患者中，通常难以获得适当的心尖观来评估 VTI。肋缘下观更容易获得，但由于多普勒信号与 LVOT 血流之间的夹角不合适，因此仅能进行心脏的定性评估，无法准确估计 LVOT VTI。我们提出了一种新的改良肋缘下观，可用于准确测量 LVOT VTI。
这是一项单中心、回顾性、观察性研究，使用来自三级保健中心患者的数据。我们纳入了 2020 年 6 月至 2022 年 1 月期间入住重症监护病房的成年患者，对其进行超声心动图检查，并在心尖五腔心观和改良肋缘下观同时使 LVOT VTI 与多普勒信号对齐的情况下测量 LVOT VTI。
在研究期间，共有 30 例患者接受了超声检查。LVOT VTI 在心尖观与肋缘下观测量值的 Bland-Altman 方法分析显示，两者之间存在 0.8 的偏差（95%CI：0.39-1.21），95%置信区间（CI）的一致性界限为-1.35（95%CI：-2.06 至 -0.64）和 2.96（95%CI：2.25-3.67）。计算出的百分比误差为 23%。两种测量方式的 Pearson 相关系数显示 R 值为 0.98（95%CI：0.96-0.99）。
改良肋缘下观测量的 LVOT VTI 可用于估计心尖观获得的 LVOT VTI 值。
