Limits...
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.

Show MeSH

Related in: MedlinePlus

CItd-CIpc was also significantly associated to CIpc itself: rpart = -0.466; p < 0.001 (merged data). CItd: Thermodilution-derived Cardiac Index. CIpc: Pulse-contour-derived Cardiac Index. CItd(base): Cardiac index measured at previous (baseline) thermodilution. Dashed lines represent the limits of the 95%-bootstrap-confidence-intervals for the regression line (solid line).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig4: CItd-CIpc was also significantly associated to CIpc itself: rpart = -0.466; p < 0.001 (merged data). CItd: Thermodilution-derived Cardiac Index. CIpc: Pulse-contour-derived Cardiac Index. CItd(base): Cardiac index measured at previous (baseline) thermodilution. Dashed lines represent the limits of the 95%-bootstrap-confidence-intervals for the regression line (solid line).

Mentions: Similarly to the data based on one data set per patient (Figures 1 and 2 and Table 3), the interval to last TPTD was not associated to the bias CItd-CIpc when including repeated data sets for correlation analysis. Comparison of bias CItd-CIpc to “time to last calibration” provided poor coefficients of partial correlation rpart and p-values in evaluation-collective (rpart = -0.09; p = 0.536), validation-collective (rpart =0.083; p = 0.605) and merged data (rpart = 0.076; p = 0.363). As demonstrated in Table 4 and Figure 3, bias CItd-CIpc was most strongly associated to the difference CIpc-CItd(base) (rpart = -0.592 (evaluation-collective), rpart = -0.630 (validation-collective) and rpart = -0.606 (merged data); p < 0.001 for both collectives and merged data). The second strongest predictor of the bias CItd-CIpc was CIpc itself (rpart = -0.367 (evaluation), rpart = -0.573 (validation) and rpart = -0.466 (merged data; p < 0.001 for both collectives and merged data; Table 4; Figure 4).Table 4


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)

CItd-CIpc was also significantly associated to CIpc itself: rpart = -0.466; p < 0.001 (merged data). CItd: Thermodilution-derived Cardiac Index. CIpc: Pulse-contour-derived Cardiac Index. CItd(base): Cardiac index measured at previous (baseline) thermodilution. Dashed lines represent the limits of the 95%-bootstrap-confidence-intervals for the regression line (solid line).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig4: CItd-CIpc was also significantly associated to CIpc itself: rpart = -0.466; p < 0.001 (merged data). CItd: Thermodilution-derived Cardiac Index. CIpc: Pulse-contour-derived Cardiac Index. CItd(base): Cardiac index measured at previous (baseline) thermodilution. Dashed lines represent the limits of the 95%-bootstrap-confidence-intervals for the regression line (solid line).
Mentions: Similarly to the data based on one data set per patient (Figures 1 and 2 and Table 3), the interval to last TPTD was not associated to the bias CItd-CIpc when including repeated data sets for correlation analysis. Comparison of bias CItd-CIpc to “time to last calibration” provided poor coefficients of partial correlation rpart and p-values in evaluation-collective (rpart = -0.09; p = 0.536), validation-collective (rpart =0.083; p = 0.605) and merged data (rpart = 0.076; p = 0.363). As demonstrated in Table 4 and Figure 3, bias CItd-CIpc was most strongly associated to the difference CIpc-CItd(base) (rpart = -0.592 (evaluation-collective), rpart = -0.630 (validation-collective) and rpart = -0.606 (merged data); p < 0.001 for both collectives and merged data). The second strongest predictor of the bias CItd-CIpc was CIpc itself (rpart = -0.367 (evaluation), rpart = -0.573 (validation) and rpart = -0.466 (merged data; p < 0.001 for both collectives and merged data; Table 4; Figure 4).Table 4

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
Related in: MedlinePlus