Bioreactance reliably detects preload responsiveness by the end-expiratory occlusion test when averaging and refresh times are shortened

Abstract

Background The end-expiratory occlusion (EEXPO) test detects preload responsiveness, but it is 15 s long and induces small changes in cardiac index (CI). It is doubtful whether the Starling bioreactance device, which averages CI over 24 s and refreshes the displayed value every 4 s (Starling-24.4), can detect the EEXPO-induced changes in CI (ΔCI). Our primary goal was to test whether this Starling device version detects preload responsiveness through EEXPO. We also tested whether shortening the averaging and refresh times to 8 s and one second, respectively, (Starling-8.1) improves the accuracy of the device in detecting preload responsiveness using EEXPO. Methods In 42 mechanically ventilated patients, during a 15-s EEXPO, we measured ∆CI through calibrated pulse contour analysis (CIpulse, PiCCO2 device) and using the Starling device. For the latter, we considered both CIStarling-24.4 from the commercial version and CIStarling-8.1 derived from the raw data. For relative ∆CIStarling-24.4 and ∆CIStarling-8.1 during EEXPO, we calculated the area under the receiver operating characteristic curve (AUROC) to detect preload responsiveness, defined as an increase in CIpulse ≥ 10% during passive leg raising (PLR). For both methods, the correlation coefficient vs. ∆CIpulse was calculated. Results Twenty-six patients were preload responders and sixteen non preload-responders. The AUROC for ∆CIStarling-24.4 was significantly lower compared to ∆CIStarling-8.1 (0.680 ± 0.086 vs. 0.899 ± 0.049, respectively; p = 0.027). A significant correlation was observed between ∆CIStarling-8.1 and ∆CIpulse (r = 0.42; p = 0.009), but not between ∆CIStarling-24.4 and ∆CIpulse. During PLR, both ∆CIStarling-24.4 and ∆CIStarling-8.1 reliably detected preload responsiveness. Conclusions Shortening the averaging and refresh times of the bioreactance signal to 8 s and one second, respectively, increases the reliability of the Starling device in detection of EEXPO-induced ∆CI. Trial registration: No. IDRCB:2018-A02825-50. Registered 13 December 2018.

Testing preload responsiveness by the tidal volume challenge assessed by the plethysmographic perfusion index

“…We thought it was unethical to administer a uid bolus even in the presence of preload responsiveness in critically ill patients -including some with ARDS -in whom an increased uid balance is an independent risk factor of mortality [29]. Nevertheless, PLR has proven to be very reliable in predicting uid responsiveness [30] and was used in previous studies to de ne preload responsiveness [11,28,31,32]. Accordingly, among the patients with a positive PLR test and who received uid, all were uid responsive.…”

Advantages and limitations of noninvasive devices for cardiac output monitoring: a literature review

“…A more recent meta-analysis, including only the most recent studies using a new mathematical model defining the so-called electrical cardiometry or velocimetry, confirmed the poor agreement of the technique (mean percentage of error of 48%) [44]. Although the limits of agreement for thoracic bioreactance were found to be high in critically-ill patients and in the perioperative context [41,45–47], the trending ability was good to follow even small cardiac output changes, as during end-expiratory occlusion test to predict fluid responsiveness [48 ▪ ]. Furthermore, some studies underlined its potential usefulness in particular situations, when used for instance as a hemodynamic tool during pregnancy [49] or thoracic surgery [14].…”