Non-Invasive Cardiac Output Monitoring in Cardiogenic Shock: The NICOM Study

Background: The bioreactance technique is a relatively new, totally noninvasive technique that is used to measure cardiac output (CO) and is easy to use. The Non-Invasive Cardiac Output Monitor (NICOM) is 1 such system. Although approved by the Food and Drug Administration for measurement of stroke volume, there is a paucity of literature validating this technology in decompensated heart failure and cardiogenic shock.

Methods and results: Fifty patients admitted to our cardiac intensive care unit for cardiogenic shock and Swan-Ganz catheter-guided therapy were prospectively enrolled in the study after informed consent. Simultaneous measurements of CO were obtained using NICOM, indirect Fick and bolus thermodilution. The intraclass correlation coefficient (ICC) was used to assess the precision of NICOM for CO using the 3 repeated measurements of CO over the pooled data. The agreement of the NICOM device in the defined clinical population, compared to indirect Fick and thermodilution, was evaluated by comparing the Pearson correlation coefficient, the Bland-Altman plot and the Lin concordance correlation coefficient. The ICC for cardiac output measured by NICOM showed excellent repeatability (ICC = 0.93, 95% CI = 0.92-0.94, n = 262) in the pooled data. The Pearson correlation coefficient for cardiac output measured by NICOM was poor when compared to indirect Fick (n = 263, r = 0.132, P = 0.033) and TD (n = 258, r = 0.275, P < 0.001).

Conclusions: NICOM technology is not a reliable method of measuring CO in patients with decompensated heart failure and cardiogenic shock.