Equivalence of bioimpedance and thermodilution in measuring cardiac index after cardiac surgery

Objective: To compare thoracic electrical bioimpedance (TEB) cardiography versus pulmonary artery thermodilution (TD) derived cardiac index in patients after cardiopulmonary bypass.

Design: Prospective, blinded electronic data collection.

Setting: Intensive care unit of a military hospital.

Participants: Post-cardiopulmonary bypass patients for primary comparison between technologies (n = 20) and patients for comparison of variability within each technology (n = 20).

Interventions: None.

Measurements and main results: Cardiac index values by TEB or TD were collected simultaneously. Linear regression, Lin's concordance correlation coefficient, bias, and precision measures within the large data set group and within each patient over time were calculated. Linearity in regression and Lin's concordance correlation coefficient of 0.99 were shown. A bias of 0.07 L/min/m(2) and precision of 0.40 L/min/m(2) were within acceptable clinical limits, as were equivalence test results.

Conclusions: TEB is equivalent to TD-derived cardiac index in postoperative cardiac surgery patients.