Evaluation of a new advanced thoracic bioimpedance device for estimation of cardiac output

Objective. This study is an evaluation of a new thoracic bioimpedance cardi ac output monitoring system which incorporates a modified form of the Kubic ek equation and a method of estimating the left ventricular ejection time f rom the time derivative bioimpedance signals. Methods.The performance of th e new system was compared with conventional thermodilution in a porcine mod el. One hundred and ninety nine (n = 199) paired measurements of thermodilu tion cardiac output (TDCO) (range 1.20-18.00 L/min) and thoracic bioimpedan ce cardiac output (BICO) were collected in 7 pigs. The bioimpedance measure ments were adjusted for the animal's weight and chest circumference, thus c ompensating for the differences in the anatomy of pigs when compared to hum ans. Data were compared using weighted correlation coefficient and Bland-Al tman analysis. Results. The weighted correlation coefficient between TDCO a nd BICO values was 0.87 (n = 199). The Bland-Altman technique yielded a pre cision of the device of +/-1.69 L/min with a bias of 0.11 L/min. Conclusion . The results from the porcine study show that the new system performed wel l over a wide range of cardiac outputs, comparing favorably with data from other new bioimpedance cardiac output devices currently available in the ma rket.