Correlation of carotid blood flow and corrected carotid flow time with invasive cardiac output measurements

Abstract

BackgroundNon-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)2/4 × velocity time integral × heart rate. Measurements were obtained using a single carotid waveform and an average of three carotid waveforms for both measures.ResultsSingle 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.ConclusionsCarotid blood flow may be a better marker of cardiac output and less subject to measurements issues than corrected carotid flow time.Electronic supplementary materialThe online version of this article (doi:10.1186/s13089-017-0065-0) contains supplementary material, which is available to authorized users.

Ultrasound Assessment of the Change in Carotid Corrected Flow Time in Fluid Responsiveness in Undifferentiated Shock

“…First, it is not a simple metric of preload but also depends on heart rate, inotropy and afterload conditions [4, 39, 40]. Second, its absolute duration does not correlate with the SV [41]. Instead, the change in duration of ccFT can identify changes in left ventricular stroke volume due to altered loading conditions.…”

Pathophysiology, echocardiographic evaluation, biomarker findings, and prognostic implications of septic cardiomyopathy: a review of the literature

“…However, measures of preload, such as central venous pressure (CVP) and inferior vena cava (IVC) dimensions, provide limited information on underlying cardiac function. Even when volume responsiveness is suggested by low CVP, increased respiratory variation of IVC diameter, or other invasive methods, guidance of resuscitation based on these measures has not been found to improve outcomes [ 14 – 16 ].…”

Relation Between Neck Skin Temperature Measurement and Carotid Artery Stenosis: In-Vitro Evaluation

“…In the work of Wada et al [16], the average blood flow volume, from 60 carotid artery samples (30 study participants), was found to be in the range of 5.4-13.1 mL/s. Similarly, Ma et al [17] reported these values to be in the range of 6.5-13.5 m/s for 51 study participants. In our recent work [13], instantaneous peak systolic and end diastolic blood flow volume rates were reported for eight carotid artery samples (four study participants).…”