NONINVASIVE MEASUREMENT OF CARDIAC-OUTPUT - WHOLE-BODY IMPEDANCE CARDIOGRAPHY IN SIMULTANEOUS COMPARISON WITH THERMODILUTION AND DIRECT OXYGEN FICK METHODS

Objective: To determine the reliability of whole-body impedance cardio graphy (ICG(WB)), with electrodes attached to wrists and ankles, in th e measurement of cardiac output (GO) on the basis of simultaneous comp arison with thermodilution (TD) and direct oxygen Fick (Fick) methods. Design: Prospective clinical study. Setting: A surgical intensive car e unit at a university hospital. Patients: Thirty consecutive subjects undergoing a coronary artery bypass surgery were investigated preoper atively. Measurements: ICG(WB) derived CO was measured simultaneously with the TD and Pick methods to establish the biases and limits of agr eement (LA) between the methods. Results: The results obtained by ICG, and the invasive methods showed good agreement. The bias and LA betwe en COTD and COICG were 0.00 l/min; -1.37 and 1.37 l/ min, respectively , and were close to those obtained between COTD and COFICK, 0.32 l/min ; 1.74 and -1.10 l/min. The bias and LA between the COFICK and COICG w ere -0.32 l/min; -2.24 and 1.60 l/min respectively. The repeatability value of consecutive single measurements for ICG(WB) (RVICG = 0.57 l/m in) was much better than for the TD method (RVTD = 1.10 l/min). Conclu sion: There was close agreement between the results of the three metho ds in the measurement of CO. In sedated preoperative patients the accu racy of ICG(WB) is within clinically acceptable limits and its repeata bility is excellent. ICG(WB) provides a useful alternative to the TD a nd Fick methods in cases where the pressures supplied by the pulmonary artery catheter are not essential.