Can we obtain a noninvasive and continuous estimation of cardiac output? Comparison between three noninvasive methods

The Validation of Cardiac Index and Stroke-Volume Variation Measured by the Pulse-Wave Transit Time-Analysis Versus Conventional Pulse-Contour Analysis After Off-Pump Coronary Artery Bypass Grafting: Observational Study

OBJECTIVE

To compare the reliability of cardiac index (CI) and stroke-volume variation (SVV) measured by the pulse-wave transit-time (PWTT) method using estimated continuous cardiac output (esCCO) technique with conventional pulse-contour analysis after off-pump coronary artery bypass grafting (OPCAB).

DESIGN

A single-center, prospective, observational study.

SETTING

At a 1,000-bed university hospital.

PARTICIPANTS

A total of 21 patients were enrolled after elective OPCAB.

INTERVENTIONS

The study authors performed a method comparison study with simultaneous measurement of CI and SVV based on the esCCO technique (CI_esCCO and esSVV, correspondingly) and pulse-contour analysis (CI_PCA and SVV_PCA, correspondingly). As a secondary analysis, they also assessed the trending ability of CI_esCCO versus CI_PCA. MEASUREMENTS AND MAIN RESULTS: The authors analyzed 178 measurement pairs for CI, and 174 pairs for SVV during the 10 study stages. The mean bias between CI_esCCO and CI_PCA was 0.06 L min/m², with limits of agreement of ± 0.92 L min/m² and a percentage error (PE) of 35.3%. The analysis of the trending ability of CI measured by PWTT revealed a concordance rate of 70%. The mean bias between esSVV and SVV_PCA was -6.1%, with limits of agreement of ± 15.5% and a PE of 137%.

CONCLUSIONS

The overall performance of CI_esCCO and esSVV versus CI_PCA and SVV_PCA is not clinically acceptable. A further improvement of the PWTT algorithm may be required for an accurate and precise assessment of CI and SVV.

Continuous Estimation of Cardiac Output in Critical Care: A Noninvasive Method Based on Pulse Wave Transit Time Compared with Transpulmonary Thermodilution

Purpose

Estimation of cardiac output (CO) and evaluation of change in CO as a result of therapeutic interventions are essential in critical care medicine. Whether noninvasive tools estimating CO, such as continuous cardiac output (esCCOTM) methods, are sufficiently accurate and precise to guide therapy needs further evaluation. We compared esCCOTM with an established method, namely, transpulmonary thermodilution (TPTD). Patients and Methods. In a single center mixed ICU, esCCOTM was compared with the TPTD method in 38 patients. The primary endpoint was accuracy and precision. The cardiac output was assessed by two investigators at baseline and after eight hours.

Results

In 38 critically ill patients, the two methods correlated significantly (r = 0.742). The Bland–Altman analysis showed a bias of 1.6 l/min with limits of agreement of −1.76 l/min and +4.98 l/min. The percentage error for CO_esCCO was 47%. The correlation of trends in cardiac output after eight hours was significant (r = 0.442), with a concordance of 74%. The performance of CO_esCCO could not be linked to the patient's condition.

Conclusion

The accuracy and precision of the esCCOTM method were not clinically acceptable for our critical patients. EsCCOTM also failed to reliably detect changes in cardiac output.

A retrospective study of traditional Chinese medicine as an adjunctive therapy for patients with chronic heart failure

This study retrospectively evaluated the effectiveness and safety of traditional Chinese medicine Shenqilixin Formula (SQLXF) as an adjunctive intervention for treating patients with chronic heart failure (CHF).This retrospective study included 135 patients with CHF. They were allocated to a treatment group or a control group according to the different treatments they received. Seventy five patients in the treatment group underwent SQLXF plus routine treatment, while 60 subjects in the control group received routine treatment only. The primary outcome was cardiac function. It was measured by the left ventricular end diastolic diameter (LVDD), left ventricular ejection fraction (LVEF), cardiac output (CO), every cardiac output (ECO), and cardiac index (CI). The secondary outcome included motor function. It was measured by the standard 6-MinuteWalk Test (6MWT). In addition, adverse events (AEs) were also recorded.Compared to subjects in the control group, patients in the treatment group revealed greater effectiveness in cardiac function, measured by LVEF (P < .05), CO (P < .05), and ECO (P < .05), and motor function, measured by the 6MWT scale (P < .05). Moreover, no significant differences of AEs were found between the 2 groups.SQLXF as an adjunctive therapy to routine treatment may help to improve both cardiac and motor function in patients with CHF.

Estimated continuous cardiac output based on pulse wave transit time in off-pump coronary artery bypass grafting: a comparison with transpulmonary thermodilution

To evaluate the accuracy of estimated continuous cardiac output (esCCO) based on pulse wave transit time in comparison with cardiac output (CO) assessed by transpulmonary thermodilution (TPTD) in off-pump coronary artery bypass grafting (OPCAB). We calibrated the esCCO system with non-invasive (Part 1) and invasive (Part 2) blood pressure and compared with TPTD measurements. We performed parallel measurements of CO with both techniques and assessed the accuracy and precision of individual CO values and agreement of trends of changes perioperatively (Part 1) and postoperatively (Part 2). A Bland-Altman analysis revealed a bias between non-invasive esCCO and TPTD of 0.9 L/min and limits of agreement of ±2.8 L/min. Intraoperative bias was 1.2 L/min with limits of agreement of ±2.9 L/min and percentage error (PE) of 64 %. Postoperatively, bias was 0.4 L/min, limits of agreement of ±2.3 L/min and PE of 41 %. A Bland-Altman analysis of invasive esCCO and TPTD after OPCAB found bias of 0.3 L/min with limits of agreement of ±2.1 L/min and PE of 40 %. A 4-quadrant plot analysis of non-invasive esCCO versus TPTD revealed overall, intraoperative and postoperative concordance rate of 76, 65, and 89 %, respectively. The analysis of trending ability of invasive esCCO after OPCAB revealed concordance rate of 73 %. During OPCAB, esCCO demonstrated poor accuracy, precision and trending ability compared to TPTD. Postoperatively, non-invasive esCCO showed better agreement with TPTD. However, invasive calibration of esCCO did not improve the accuracy and precision and the trending ability of method.