Cardiac Output Measurement Using the Non-Invasive Cardiac Output (NICO) Monitor: A Comparative Study with the Standard Thermodilution Technique

(Second Department of Surgery and Intensive Care Unit*, Gunma University, School of Medicine, Maebashi, Japan)

Chieri Kimura Fumio Kunimoto* Yasuo Morishita
The non-invasive cardiac output (NICO) monitor is a new device in order to measure cardiac output (CO). A rebreathing circuit is built in the NICO monitor and CO is calculated using the Fick CO2 equation. We compared this technique with the standard thermodilution (TDCO) technique in patients with thoracic and abdominal surgery. Thirty-two paired data were obtained in 17 patients. Correlation between the two methods in patients with controlled mechanical ventilation (CMV) was fair, with a correlation coefficient of 0.85. However, the correlation coefficient of the two methods was 0.60 in spontaneous breathing patients. Bland-Altman analysis showed a bias of 0.24±0.68 (mean±2SD) in CMV patients and 1.44±1.28 in spontaneous breathing patients. The NICO value was inversely proportional to an end-tidal CO2 difference (ΔETCO2) between pre-rebreathing and post-rebreathing. The large bias in spontaneously breathing patients might be due to a small ΔETCO2 in spontaneously breathing patients. The NICO monitor has a tendency to measure higher CO values in spontaneously breathing patients.
@Jpn. J. Cardiovasc. Surg. 33: 6 -8 (2004)