Can endotracheal bioimpedance cardiography assess hemodynamic response to passive leg raising following cardiac surgery?

Abstract

BackgroundThe utility of endotracheal bioimpedance cardiography (ECOM) has been scarcely reported. We tested the hypothesis that it could be an alternative to pulse contour analysis for cardiac index measurement and prediction in fluid responsiveness.MethodsTwenty-five consecutive adult patients admitted to the intensive care unit following conventional cardiac surgery were prospectively included and investigated at baseline, during passive leg raising, and after fluid challenge. Comparative cardiac index data points were collected from pulse contour analysis (CIPC) and ECOM (CIECOM). Correlations were determined by linear regression. Bland-Altman analysis was used to compare the bias, precision, and limits of agreement. Percentage error was calculated. Changes in CIPC (ΔCIPC) and CIECOM (ΔCIECOM) during passive leg raising were collected to assess their discrimination in predicting fluid responsiveness.ResultsA significant relationship was found between CIPC and CIECOM (r = 0.45; P < 0.001). Bias, precision, and limits of agreement were 0.44 L.min-1.m-2 (95% confidence interval, 0.33-0.56), 0.59 L.min-1.m-2, and −0.73 to 1.62 L.min-1.m-2, respectively. Percentage error was 45%. A significant relationship was found between percent changes in CIPC and CIECOM after fluid challenge (r = 0.42; P = 0.035). Areas under the ROC curves for ΔCIPC and ΔCIECOM to predict fluid responsiveness were 0.72 (95% confidence interval, 0.5–0.88) and 0.81 (95% confidence interval, 0.61-0.94), respectively.ConclusionsECOM is not interchangeable with pulse contour analysis but seems consistent to monitor cardiac index continuously and could help to predict fluid responsiveness by using passive leg raising.

Prediction of fluid responsiveness: an update

“…Bioreactance has been investigated with conflicting results [64, 66]. Endotracheal bioimpedance cardiography was reported to be unable to assess the haemodynamic response to a PLR test [67]. The totally non-invasive estimation of cardiac output by pulse contour analysis of the arterial curve obtained from photoplethysmography is also suitable for the PLR test, which may be particularly interesting out of the ICU and the operating room.…”

Assessment of volume responsiveness during mechanical ventilation: recent advances

“…This aspect is particularly true in septic patients in whom capillary leak may account for an attenuation of the PLR effects after one minute, as already described [22]. This is why clinical studies that have tested the value of PLR to predict volume responsiveness used real-time hemodynamic measurements, such as aortic blood flow measured by esophageal Doppler [22,41], pulse contour analysis-derived cardiac output [16,26,42], cardiac output measured by bioreactance [43,44] or endotracheal bioimpedance cardiography [45], subaortic blood velocity measured by echocardiography [46-48], ascending aortic velocity measured by suprasternal Doppler [49] and, more recently, end-tidal carbon dioxide [50,51]. …”

Assessment of Volume Responsiveness During Mechanical Ventilation: Recent Advances

“…Th is aspect is particularly true in septic patients in whom capillary leak may account for an attenuation of the PLR eff ects after one minute, as already described [22]. Th is is why clinical studies that ha ve tested the value of PLR to predict volume responsiveness used real-time hemodynamic measurements, such as aortic blood fl ow measured by esophageal Doppler [22,41], pulse contour analysis-derived ca rdiac output [16,26,42], cardiac output measured by bio reacta nce [4 3,44] or endotracheal bioimpedance cardi ograph y [45], subaortic blood velocity measured by echocardiography [46][47][48], ascending aortic velocity measure d by s uprasternal Doppler [49] and, more recently, end-tidal carbon dioxide [50,51].…”