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Assessment of stroke volume index with three different bioimpedance algorithms: lack of agreement compared to thermodilution.

ABSTRACT: OBJECTIVE: The accuracy of bioimpedance stroke volume index (SVI) is questionable as studies report inconsistent results. It remains unclear whether the algorithms alone are responsible for these findings. We analyzed the raw impedance data with three algorithms and compared bioimpedance SVI to transpulmonary thermodilution (SVI(TD)). DESIGN AND SETTING: Prospective observational clinical study in a university hospital. PATIENTS: Twenty adult patients scheduled for coronary artery bypass grafting (CABG). INTERVENTIONS: SVI(TD) and bioimpedance parameters were simultaneously obtained before surgery (t1), after bypass (t2), after sternal closure (t3), at the intensive care unit (t4), at normothermia (t5), after extubation (t6) and before discharge (t7). Bioimpedance data were analyzed off-line using cylinder (Kubicek: SVI(K); Wang: SVI(W)) and truncated cone based algorithms (Sramek-Bernstein: SVI(SB)). MEASUREMENTS AND RESULTS: Bias and precision between the SVI(TD) and SVI(K), SVI(SB), and SVI(W) was 1.0+/-10.8, 9.8+/-11.4, and -15.7+/-8.2 ml/m2 respectively, while the mean error was abundantly above 30%. Analysis of data per time moment resulted in a mean error above 30%, except for SVI(W) at t2 (28%). CONCLUSIONS: Estimation of SVI by cylinder or truncated cone based algorithms is not reliable for clinical decision making in patients undergoing CABG surgery. A more robust approach for estimating bioimpedance based SVI may exclude inconsistencies in the underlying algorithms in existing thoracic bioimpedance cardiography devices.

SUBMITTER: de Waal EE

PROVIDER: S-EPMC2271085 | biostudies-other | 2008 Apr

REPOSITORIES: biostudies-other

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Assessment of stroke volume index with three different bioimpedance algorithms: lack of agreement compared to thermodilution.

de Waal Eric E C EE Konings Maurits K MK Kalkman Cor J CJ Buhre Wolfgang F WF

Intensive care medicine 20080108 4

<h4>Objective</h4>The accuracy of bioimpedance stroke volume index (SVI) is questionable as studies report inconsistent results. It remains unclear whether the algorithms alone are responsible for these findings. We analyzed the raw impedance data with three algorithms and compared bioimpedance SVI to transpulmonary thermodilution (SVI(TD)).<h4>Design and setting</h4>Prospective observational clinical study in a university hospital.<h4>Patients</h4>Twenty adult patients scheduled for coronary ar ...[more]

PMID: 18188539

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Project description:BackgroundLameness assessment in horses is still predominantly performed using subjective methods. Visual assessment is known to have moderate to good intra-rater agreement but relatively poor inter-rater agreement. Little is known about inter- and intra-rater agreement on the evaluation of back motion, for which no objective measurement technique in a clinical setting is available thus far.ObjectivesTo describe inter- and intra-rater agreement of visual evaluation of equine back mobility.Study designRater reliability study using a fully crossed design in which all horses are rated by all observers. This data is compared with objective gait analysis.MethodsSeventy equine professionals (veterinarians and physiotherapists) and veterinary students evaluated videos of 12 healthy horses at walk and trot on a hard, straight line. Nine parameters related to back mobility were scored: general mobility, thoracic, lumbar, lumbosacral flexion and extension and left and right thoracolumbar latero-flexion. All parameters were compared with simultaneously measured quantitative motion parameters. After 1 month, six randomly chosen horses were re-evaluated by 57 observers.ResultsFor each parameter inter- and intra-rater agreements were calculated using intra-class correlation coefficients. For all parameters, inter-rater agreement was very poor (<0.2). The mean intra-rater agreement of all observers and for all parameters was poor (~0.4) but varied between 0.0 and 0.96 for individual observers. There was no correlation between the visual subjective scoring and objective gait analysis measurements.Main limitationsHorses were scored from videos and by lack of any existing (semi-) quantitative system, a custom-made system had to be used.ConclusionsThe poor inter- and intra-rater agreements of visual scoring of mobility of the equine back and the disagreement between subjective and objective gait analysis data, demonstrate the need for the development and introduction of objective, quantitative and repeatable techniques to assess equine back motion.

Dataset Information

Assessment of stroke volume index with three different bioimpedance algorithms: lack of agreement compared to thermodilution.

Publications

Assessment of stroke volume index with three different bioimpedance algorithms: lack of agreement compared to thermodilution.

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