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Predictors of the accuracy of pulse-contour cardiac index and suggestion of a calibration-index: a prospective evaluation and validation study.

Huber W, Koenig J, Mair S, Schuster T, Saugel B, Eyer F, Phillip V, Schultheiss C, Thies P, Mayr U, Einwächter H, Treiber M, Hoellthaler J, Schmid RM - BMC Anesthesiol (2015)

Bottom Line: CIpc-values at baseline and after intervals of 1 h, 2 h, 4 h, 6 h and 8 h were compared to CItd derived from immediately subsequent TPTD.In the merged data, percentage-error was below 30% after 1 h, 2 h, 4 h and 8 h, and exceeded 30% only after 6 h. "Time to last calibration" was neither associated to accuracy nor to precision of CIpc in any uni- or multivariate analysis.Recalibration triggered by changes of CIpc compared to CItd(base) derived from last calibration should be preferred to fixed intervals.

View Article: PubMed Central - PubMed

Affiliation: II. Medizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Ismaninger Strasse 22, D-81675 Munich, Germany.

ABSTRACT

Background: Cardiac Index (CI) is a key-parameter of hemodynamic monitoring. Indicator-dilution is considered as gold standard and can be obtained by pulmonary arterial catheter or transpulmonary thermodilution (TPTD; CItd). Furthermore, CI can be estimated by Pulse-Contour-Analysis (PCA) using arterial wave-form analysis (CIpc). Obviously, adjustment of CIpc to CItd initially improves the accuracy of CIpc. Despite uncertainty after which time accuracy of CIpc might be inappropriate, recalibration by TPTD is suggested after a maximum of 8 h. We hypothesized that accuracy of CIpc might not only depend on time to last TPTD, but also on changes of the arterial wave curve detectable by PCA itself. Therefore, we tried to prospectively characterize predictors of accuracy and precision of CIpc (primary outcome). In addition to "time to last TPTD" we evaluated potential predictors detectable solely by pulse-contour-analysis. Finally, the study aimed to develop a pulse-contour-derived "calibration-index" suggesting recalibration and to validate these results in an independent collective.

Methods: In 28 intensive-care-patients with PiCCO-monitoring (Pulsion Medical-Systems, Germany) 56 datasets were recorded. CIpc-values at baseline and after intervals of 1 h, 2 h, 4 h, 6 h and 8 h were compared to CItd derived from immediately subsequent TPTD. Results from this evaluation-collective were validated in an independent validation-collective (49 patients, 67 datasets).

Results: Mean bias values CItd-CIpc after different intervals ranged between -0.248 and 0.112 L/min/m(2). Percentage-error after different intervals to last TPTD ranged between 18.6% (evaluation, 2 h-interval) and 40.3% (validation, 6 h-interval). In the merged data, percentage-error was below 30% after 1 h, 2 h, 4 h and 8 h, and exceeded 30% only after 6 h. "Time to last calibration" was neither associated to accuracy nor to precision of CIpc in any uni- or multivariate analysis. By contrast, the height of CIpc and particularly changes in CIpc compared to last thermodilution-derived CItd(base) univariately and independently predicted the bias CItd-CIpc in both collectives. Relative changes of CIpc compared to CItd(base) exceeding thresholds derived from the evaluation-collective (-11.6% < CIpc-CItd(base)/CItd(base) < 7.4%) were confirmed as significant predictors of a bias /CItd-CIpc/ ≥ 20% in the validation-collective.

Conclusion: Recalibration triggered by changes of CIpc compared to CItd(base) derived from last calibration should be preferred to fixed intervals.

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Thermoplot demonstrating “Area under the Curve” (AUC) values from Receiver Operating Characteristic (ROC)-analyses regarding bias CIt-CIpc exceeding ≥20% of CItd. Y-axis ranges from 0.5 (worthless for prediction; intense blue) to 1.0 (best prediction; intense red). The variables were aligned according to merged data. CItd: Thermodilution-derived Cardiac Index. CIpc: Pulse-contour-derived Cardiac Index. CItd(base): Cardiac index measured at previous (baseline) thermodilution. dPmax: “Index of Left Ventricular Contractility”. PP: Pulse Pressure. TPTD: Transpulmonary thermodilution. MAP: mean arterial pressure. RRsyst, RRdiast: systolic and diastolic pressure. HR: Heart rate. Δ-values compare data to corresponding values at the time of the last TPTD. [rel]: relative changes compared to time of the last TPTD. [abs]: absolute changes compared to time of the last TPTD.
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Fig5: Thermoplot demonstrating “Area under the Curve” (AUC) values from Receiver Operating Characteristic (ROC)-analyses regarding bias CIt-CIpc exceeding ≥20% of CItd. Y-axis ranges from 0.5 (worthless for prediction; intense blue) to 1.0 (best prediction; intense red). The variables were aligned according to merged data. CItd: Thermodilution-derived Cardiac Index. CIpc: Pulse-contour-derived Cardiac Index. CItd(base): Cardiac index measured at previous (baseline) thermodilution. dPmax: “Index of Left Ventricular Contractility”. PP: Pulse Pressure. TPTD: Transpulmonary thermodilution. MAP: mean arterial pressure. RRsyst, RRdiast: systolic and diastolic pressure. HR: Heart rate. Δ-values compare data to corresponding values at the time of the last TPTD. [rel]: relative changes compared to time of the last TPTD. [abs]: absolute changes compared to time of the last TPTD.

Mentions: Bias values exceeding ±15%, ±20% and ±0.5 L/min/m2 in general were best predicted by absolute or relative changes in CIpc compared to CItd derived from the previous TPTD (CIpc-CItd(base)). Figure 5 (thermoplot) demonstrates ROC-AUCs regarding bias values exceeding ±20%.Figure 5


Predictors of the accuracy of pulse-contour cardiac index and suggestion of a calibration-index: a prospective evaluation and validation study.

Huber W, Koenig J, Mair S, Schuster T, Saugel B, Eyer F, Phillip V, Schultheiss C, Thies P, Mayr U, Einwächter H, Treiber M, Hoellthaler J, Schmid RM - BMC Anesthesiol (2015)

Thermoplot demonstrating “Area under the Curve” (AUC) values from Receiver Operating Characteristic (ROC)-analyses regarding bias CIt-CIpc exceeding ≥20% of CItd. Y-axis ranges from 0.5 (worthless for prediction; intense blue) to 1.0 (best prediction; intense red). The variables were aligned according to merged data. CItd: Thermodilution-derived Cardiac Index. CIpc: Pulse-contour-derived Cardiac Index. CItd(base): Cardiac index measured at previous (baseline) thermodilution. dPmax: “Index of Left Ventricular Contractility”. PP: Pulse Pressure. TPTD: Transpulmonary thermodilution. MAP: mean arterial pressure. RRsyst, RRdiast: systolic and diastolic pressure. HR: Heart rate. Δ-values compare data to corresponding values at the time of the last TPTD. [rel]: relative changes compared to time of the last TPTD. [abs]: absolute changes compared to time of the last TPTD.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4389926&req=5

Fig5: Thermoplot demonstrating “Area under the Curve” (AUC) values from Receiver Operating Characteristic (ROC)-analyses regarding bias CIt-CIpc exceeding ≥20% of CItd. Y-axis ranges from 0.5 (worthless for prediction; intense blue) to 1.0 (best prediction; intense red). The variables were aligned according to merged data. CItd: Thermodilution-derived Cardiac Index. CIpc: Pulse-contour-derived Cardiac Index. CItd(base): Cardiac index measured at previous (baseline) thermodilution. dPmax: “Index of Left Ventricular Contractility”. PP: Pulse Pressure. TPTD: Transpulmonary thermodilution. MAP: mean arterial pressure. RRsyst, RRdiast: systolic and diastolic pressure. HR: Heart rate. Δ-values compare data to corresponding values at the time of the last TPTD. [rel]: relative changes compared to time of the last TPTD. [abs]: absolute changes compared to time of the last TPTD.
Mentions: Bias values exceeding ±15%, ±20% and ±0.5 L/min/m2 in general were best predicted by absolute or relative changes in CIpc compared to CItd derived from the previous TPTD (CIpc-CItd(base)). Figure 5 (thermoplot) demonstrates ROC-AUCs regarding bias values exceeding ±20%.Figure 5

Bottom Line: CIpc-values at baseline and after intervals of 1 h, 2 h, 4 h, 6 h and 8 h were compared to CItd derived from immediately subsequent TPTD.In the merged data, percentage-error was below 30% after 1 h, 2 h, 4 h and 8 h, and exceeded 30% only after 6 h. "Time to last calibration" was neither associated to accuracy nor to precision of CIpc in any uni- or multivariate analysis.Recalibration triggered by changes of CIpc compared to CItd(base) derived from last calibration should be preferred to fixed intervals.

View Article: PubMed Central - PubMed

Affiliation: II. Medizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Ismaninger Strasse 22, D-81675 Munich, Germany.

ABSTRACT

Background: Cardiac Index (CI) is a key-parameter of hemodynamic monitoring. Indicator-dilution is considered as gold standard and can be obtained by pulmonary arterial catheter or transpulmonary thermodilution (TPTD; CItd). Furthermore, CI can be estimated by Pulse-Contour-Analysis (PCA) using arterial wave-form analysis (CIpc). Obviously, adjustment of CIpc to CItd initially improves the accuracy of CIpc. Despite uncertainty after which time accuracy of CIpc might be inappropriate, recalibration by TPTD is suggested after a maximum of 8 h. We hypothesized that accuracy of CIpc might not only depend on time to last TPTD, but also on changes of the arterial wave curve detectable by PCA itself. Therefore, we tried to prospectively characterize predictors of accuracy and precision of CIpc (primary outcome). In addition to "time to last TPTD" we evaluated potential predictors detectable solely by pulse-contour-analysis. Finally, the study aimed to develop a pulse-contour-derived "calibration-index" suggesting recalibration and to validate these results in an independent collective.

Methods: In 28 intensive-care-patients with PiCCO-monitoring (Pulsion Medical-Systems, Germany) 56 datasets were recorded. CIpc-values at baseline and after intervals of 1 h, 2 h, 4 h, 6 h and 8 h were compared to CItd derived from immediately subsequent TPTD. Results from this evaluation-collective were validated in an independent validation-collective (49 patients, 67 datasets).

Results: Mean bias values CItd-CIpc after different intervals ranged between -0.248 and 0.112 L/min/m(2). Percentage-error after different intervals to last TPTD ranged between 18.6% (evaluation, 2 h-interval) and 40.3% (validation, 6 h-interval). In the merged data, percentage-error was below 30% after 1 h, 2 h, 4 h and 8 h, and exceeded 30% only after 6 h. "Time to last calibration" was neither associated to accuracy nor to precision of CIpc in any uni- or multivariate analysis. By contrast, the height of CIpc and particularly changes in CIpc compared to last thermodilution-derived CItd(base) univariately and independently predicted the bias CItd-CIpc in both collectives. Relative changes of CIpc compared to CItd(base) exceeding thresholds derived from the evaluation-collective (-11.6% < CIpc-CItd(base)/CItd(base) < 7.4%) were confirmed as significant predictors of a bias /CItd-CIpc/ ≥ 20% in the validation-collective.

Conclusion: Recalibration triggered by changes of CIpc compared to CItd(base) derived from last calibration should be preferred to fixed intervals.

Show MeSH