Cardiac cycle efficiency as prognostic index in ICUs

Introduction

Cardiac cycle efficiency (CCE) can be calculated by the pressure recording analytical method (PRAM), a mini-invasive pulse-contour system that can provide beat-to-beat monitoring of cardiac output [1]. CCE is a new parameter that ranges from -1 to +1, with -1 being the worse and +1 the best possible performance of the cardiac cycle in terms of hemodynamic balance maintenance [2]. These characteristics make CCE a possible prognostic index, especially in critical patients who often present hemodynamic instability.

Methods

We recruited 157 consecutive patients admitted to the ICU undergoing hemodynamic monitoring, and the following parameters were registered in the first 24 hours from the admission: hemodynamic parameters (cardiac index, dp/dt_max and CCE) detected from the MostCare monitor (based on the PRAM algorithm), PaO₂/FiO₂ ratio, arterial lactates, SAPS II. We also divided the patients into seven diagnostic categories and take note of the outcome.

Results

We inserted all data into the logistic regression analysis model. The significant variables that take place in the regression equation included: SAPS II (P < 0.0001), lactates (P = 0.033), dp/dt_max (P = 0.032) and the diagnostic category (P = 0.020). CCE was not significant and was not included in the model. See Table 1.

Table 1 Results of logistic regression analysis

Conclusions

We demonstrate that CCE registered in the first 24 hours from admission is not a good prognostic index. The differences of CCE value between patients with good and negative outcome was not statistically significant. This result may suggest that a low CCE value in 24 hours from admission does not necessarily mean a bad outcome but, on the contrary, can be successfully improved by a therapeutic approach. It will be interesting to study whether there are some correspondences between CCE variations and modifications of the clinical conditions of the patients that may predict a positive or negative outcome.