Measurement uncertainty in pulmonary vascular input impedance and characteristic impedance estimated from pulsed-wave Doppler ultrasound and pressure: clinical studies on 57 pediatric patients
| Autor: | Robin Shandas, Kendall S. Hunter, K. Scott Kirby, D. Dunbar Ivy, Lian Tian |
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| Jazyk: | angličtina |
| Rok vydání: | 2010 |
| Předmět: |
Male
medicine.medical_specialty Adolescent Physiology Instrumentation Acoustics Hypertension Pulmonary Population Biomedical Engineering Biophysics Blood Pressure Pulmonary Artery Characteristic impedance Article Afterload Physiology (medical) medicine Humans Intensive care medicine education Child Electrical impedance Lung Retrospective Studies education.field_of_study business.industry Uncertainty Infant Input impedance medicine.anatomical_structure Research Design Ultrasonography Doppler Pulsed Case-Control Studies Child Preschool Vascular resistance Measurement uncertainty Female business |
| Popis: | Pulmonary vascular input impedance better characterizes right ventricular (RV) afterload and disease outcomes in pulmonary hypertension compared to the standard clinical diagnostic, pulmonary vascular resistance (PVR). Early efforts to measure impedance were not routine, involving open-chest measurement. Recently, the use of pulsed-wave (PW) Doppler-measured velocity to non-invasively estimate instantaneous flow has made impedance measurement more practical. One critical concern remains with clinical use: the measurement uncertainty, especially since previous studies only incorporated random error. This study utilized data from a large pediatric patient population to comprehensively examine the systematic and random error contributions to the total impedance uncertainty and determined the least error prone methodology to compute impedance from among four different methods. We found that the systematic error contributes greatly to the total uncertainty and that one of the four methods had significantly smaller propagated uncertainty; however, even when this best method is used, the uncertainty can be large for input impedance at high harmonics and for the characteristic impedance modulus. Finally, we found that uncertainty in impedance between normotensive and hypertensive patient groups displays no significant difference. It is concluded that clinical impedance measurement would be most improved by advancements in instrumentation, and the best computation method is proposed for future clinical use of the input impedance. |
| Databáze: | OpenAIRE |
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