부산대학교 도서관

R4190 --> Introduction: The Innocor Cardiopulmonary Measurement Device is designed to measure cardiac output and stroke volume by applying the inert gas rebreathing technique. This technique utilizes an insoluble gas concentration (SF6) to estimate lung volume and a soluble gas (N2O) rate of disappearance to measure pulmonary blood flow to estimate cardiac output/stroke volume. We sought to identify sources of error in the measurement of these two gases in an effort to reduce measurement error. Methods: We enrolled 28 participants from the Dallas Heart Study (age 63 years; 57% male; 43% white). Stroke volume was measured non‐invasively using echocardiography (Philips) using the velocity time integral technique. Three separate resting stroke volume measurements were acquired using the Innocor device. We explored the contribution of peak and equilibrium gas concentrations of SF6 to variation in stroke volume measurements by quantifying these values from the graphical output. Because of the known inspired gas concentration of SF6 (0.12%), we defined peak concentrations greater than 0.12% a priori as measurement error. We compared stroke volume measurements derived from the echocardiogram with Innocor measurements where peak SF6 values were (1) greater than 0.12% (defined as "insoluble gas error") and (2) less than 0.12% (defined as "insoluble gas no error"). Results: We successfully measured stroke volume at rest 3 times in each of the 28 participants using the Innocor device for a total of 81 measurements. At the participant level, 8 (29%) had at least one measurement where SF6 was greater than or equal to 0.12%. However, all participants had at least one measured stroke volume where SF6 was less than 0.12%. As expected, the measured stroke volume was much larger for measurements where peak SF6 values were greater than or equal to 0.12% when compared to stroke volume measurements with peak SF6 values less than 0.12% (p<0.01). Furthermore, the measured stroke volume by echo was similar (p=NS) to those measurements obtained when SF6 values were less than 0.12% (see Figure). Conclusion: We identified peak inspired SF6 values from the graphical output as a common source of measurement error using the Innocor device. Furthermore, when peak SF6 was greater than or equal to 0.12% on the graphical output, the stroke volume was overestimated when compared to echocardiogram measurements of stroke volume. The application of this technique could assist in reducing measurement error with this device. [ABSTRACT FROM AUTHOR]