OBJECTIVE: This study is an evaluation of a new thoracic bioimpedance cardiac output monitoring system which incorporates a modified form of the Kubicek equation and a method of estimating the left ventricular ejection time from the time derivative bioimpedance signals. METHODS: The performance of the new system was compared with conventional thermodilution in a porcine model. One hundred and ninety nine (n = 199) paired measurements of thermodilution cardiac output (TDCO) (range 1.20-18.00 L/min) and thoracic bioimpedance cardiac output (BICO) were collected in 7 pigs. The bioimpedance measurements were adjusted for the animal's weight and chest circumference, thus compensating for the differences in the anatomy of pigs when compared to humans. Data were compared using weighted correlation coefficient and Bland-Altman analysis. RESULTS: The weighted correlation coefficient between TDCO and BICO values was 0.87 (n = 199). The Bland-Altman technique yielded a precision 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 well over a wide range of cardiac outputs, comparing favorably with data from other new bioimpedance cardiac output devices currently available in the market.
OBJECTIVE: This study is an evaluation of a new thoracic bioimpedance cardiac output monitoring system which incorporates a modified form of the Kubicek equation and a method of estimating the left ventricular ejection time from the time derivative bioimpedance signals. METHODS: The performance of the new system was compared with conventional thermodilution in a porcine model. One hundred and ninety nine (n = 199) paired measurements of thermodilution cardiac output (TDCO) (range 1.20-18.00 L/min) and thoracic bioimpedance cardiac output (BICO) were collected in 7 pigs. The bioimpedance measurements were adjusted for the animal's weight and chest circumference, thus compensating for the differences in the anatomy of pigs when compared to humans. Data were compared using weighted correlation coefficient and Bland-Altman analysis. RESULTS: The weighted correlation coefficient between TDCO and BICO values was 0.87 (n = 199). The Bland-Altman technique yielded a precision 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 well over a wide range of cardiac outputs, comparing favorably with data from other new bioimpedance cardiac output devices currently available in the market.
Authors: W C Shoemaker; C C Wo; M H Bishop; P L Appel; J M Van de Water; G R Harrington; X Wang; R S Patil Journal: Crit Care Med Date: 1994-12 Impact factor: 7.598