Objectives:
The study was designed to evaluate the reliability and accuracy of cardiac output (CO) measurement using electrical bioimpedance cardiography, (Physioflow®) (COPF), in paediatric patients with and without cardiac disease undergoing MRI.

Methods:
After Institutional Ethics Committee approval and informed consent, patients undergoing cardiac MRI were recruited. CO was calculated by flow measurement. Immediately before or after the MRI, 6 Physioflow® (PF) ECG electrodes were applied for continuous real time measurements every 15 seconds over 10 minutes (COPF). The level of patient sedation was constant for both CO measurements. CO was averaged and compared with the CO measurements using Bland-Altman analysis.

Results:
Preliminary results of 16 patients (8 males/8 females)are presented. Median age(range)was 2.8 years (0.2-8.0 years)and median(range) BSA 0.55m (0.16-1.00m). 44% of patients had intracardiac shunts,25 % had severe physiological abnormalities. Median number of PF measurements per patient was 53(21-377). A total of 959/1599 PF measurements were valid (60%). The Physioflow® was unable to calculate CI in 8% of data entries and identified 33% entries as artifact. A further 14 % data entries were deemed implausible by investigators, 33 % of these entries were not detected as such by PF. Mean CI=3.1± 1.1, mean CI=3.0± 0.5,mean bias(PF-MRI)= -0.20 p=0.40,limits of agreement(95%)= -3.40- +1.60. One third of patients had measurements within 20 % of each other, 87% of patients within 40 %. COMRI affected agreement (r=+0.86,p<0.001).

Impact:
Preliminary data demonstrate that CI is not accurate when compared to CI. Recruitment of patients with more homogenous cardiac physiology continues.