Cardiac index assessment by the pressure recording analytic method in unstable patients with atrial fibrillation

Most-Care (powered by the pressure-recording analytic method [PRAM]; Vytech HealthTM, Padova, Italy) is a minimally invasive cardiac output monitoring. This system already has been studied and validated in cardiac surgery and in children. It already showed a correlation with thermodilution methods in hemodynamically unstable patients. The purpose of this study was to confirm the reliability of cardiac index determinations by Most-Care in unstable patients with atrial fibrillation.

A prospective study.

A teaching hospital.

Forty-nine patients.

Simultaneous cardiac index measurements by bolus thermodilution and by PRAM from a standard arterial access (radial and femoral) were obtained. The thermodilution cardiac index was calculated as the mean of 3 separate measurements. Because PRAM is a beat-to-beat monitoring system, the mean cardiac index of 12 consecutive beats was considered for the analysis. Correlations were calculated and differences compared by Bland-Altman analysis.

Eight patients were excluded because the signal was altered by the arterial catheter resonance so that the study described the remaining 41 patients. The overall estimates of cardiac index measured by PRAM did not show agreement with the reference cardiac index by thermodilution (mean difference = 0.136 L/min/m(2) [0,43 L/min/m(2)-0.15 L/min/m(2)], with an upper limit of agreement of 1.94 L/min/m(2) and a lower limit of agreement of -1.665 L/min/m(2), respectively). The median (interquartile) value of cardiac index assessed by thermodilution was 2.42 L/min/m(2) (2.21-2.98 L/min/m(2)), and by PRAM it was 2.48 L/min/m(2) (1.80-3.00 L/min/m(2), p = 0.6).

The authors concluded that PRAM did not compare well with thermodilution in unstable patients with atrial fibrillation.