Ma Irene W Y, Caplin Joshua D, Azad Aftab, Wilson Christina, Fifer Michael A, Bagchi Aranya, Liteplo Andrew S, Noble Vicki E
Division of Emergency Ultrasound, Department of Emergency Medicine, Massachusetts General Hospital, 326 Cambridge Street, Suite 410, Boston, MA, 02114, USA.
Division of General Internal Medicine, Department of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary, AB, T2N 4N1, Canada.
Crit Ultrasound J. 2017 Dec;9(1):10. doi: 10.1186/s13089-017-0065-0. Epub 2017 Apr 20.
Non-invasive measures that can accurately estimate cardiac output may help identify volume-responsive patients. This study seeks to compare two non-invasive measures (corrected carotid flow time and carotid blood flow) and their correlations with invasive reference measurements of cardiac output. Consenting adult patients (n = 51) at Massachusetts General Hospital cardiac catheterization laboratory undergoing right heart catheterization between February and April 2016 were included. Carotid ultrasound images were obtained concurrently with cardiac output measurements, obtained by the thermodilution method in the absence of severe tricuspid regurgitation and by the Fick oxygen method otherwise. Corrected carotid flow time was calculated as systole time/√cycle time. Carotid blood flow was calculated as π × (carotid diameter)/4 × velocity time integral × heart rate. Measurements were obtained using a single carotid waveform and an average of three carotid waveforms for both measures.
Single waveform measurements of corrected flow time did not correlate with cardiac output (ρ = 0.25, 95% CI -0.03 to 0.49, p = 0.08), but an average of three waveforms correlated significantly, although weakly (ρ = 0.29, 95% CI 0.02-0.53, p = 0.046). Carotid blood flow measurements correlated moderately with cardiac output regardless of if single waveform or an average of three waveforms were used: ρ = 0.44, 95% CI 0.18-0.63, p = 0.004, and ρ = 0.41, 95% CI 0.16-0.62, p = 0.004, respectively.
Carotid blood flow may be a better marker of cardiac output and less subject to measurements issues than corrected carotid flow time.
能够准确估算心输出量的非侵入性测量方法可能有助于识别容量反应性患者。本研究旨在比较两种非侵入性测量方法（校正颈动脉血流时间和颈动脉血流量）及其与心输出量有创参考测量值的相关性。纳入了2016年2月至4月在马萨诸塞州总医院心脏导管实验室接受右心导管检查的成年患者（n = 51）。在进行心输出量测量的同时获取颈动脉超声图像，心输出量在无严重三尖瓣反流时通过热稀释法测量，否则通过菲克氧法测量。校正颈动脉血流时间计算为收缩期时间/√心动周期时间。颈动脉血流量计算为π×（颈动脉直径）²/4×速度时间积分×心率。两种测量方法均使用单个颈动脉波形和三个颈动脉波形的平均值进行测量。
校正血流时间的单个波形测量值与心输出量无相关性（ρ = 0.25，95%CI -0.03至0.49，p = 0.08），但三个波形的平均值有显著相关性，尽管较弱（ρ = 0.29，95%CI 0.02 - 0.53，p = 0.046）。无论使用单个波形还是三个波形的平均值，颈动脉血流量测量值与心输出量均呈中度相关：分别为ρ = 0.44，95%CI 0.18 - 0.63，p = 0.004，以及ρ = 0.41，95%CI 0.16 - 0.62，p = 0.004。
与校正颈动脉血流时间相比，颈动脉血流量可能是更好的心输出量指标，且受测量问题的影响较小。
