Ejection fraction (EF) corrected volumetric parameters better reflect preload and fluid responsiveness

Introduction

Volumetric monitoring with right ventricular end-diastolic volume indexed (RVEDVi) and global end-diastolic volume indexed (GEDVi) is increasingly being suggested as a better preload indicator than traditional intracardiac filling pressures (central venous pressure [CVP] and pulmonary artery occlusion pressure [PAOP]). Static volumetric monitoring, however, has not consistently been shown to correlate with the cardiac index (CI). This study aims (1) to evaluate the influence of ejection fraction (EF) on RVEDVi and GEDVi, (2) to study the effect of RVEDVi and GEDVi changes (Δ) corrected for right ventricle ejection fraction (RVEF) and global ejection fraction (GEF), respectively, on ΔCI, and (3) to identify optimal resuscitation target volumes.

Materials and methods

Complete hemodynamic profiles with the VoLEF and PiCCO catheter (Pulsion, Germany) were obtained in five mechanically ventilated medical ICU patients: age 62.6 ± 11.2 years, SAPS-II 41 ± 15.4, APACHE II 18.8 ± 5.4, and SOFA 4.8 ± 2.1. In total 125 paired measurements of CVP, PAOP, RVEDVi, RVEF, GEDVi, GEF and CI were performed.

Results

Figure 1 shows the correlation of ΔRVEDVi corrected for RVEF (ΔRVEDVi-C) with ΔCI (R² = 0.69, P < 0.0001). Figure 2 shows a similar correlation between ΔGEDVi corrected for GEF(ΔGEDVi-C) with ΔCI (R² = 0.62, P < 0.0001). Adjustment of volumes was achieved by exponential correction for the EF deviation from normal (Fig. 3). The RVEDVi-C and GEDVi-C volumetric targets corrected for EF are presented in Table 1. We did not found any correlation between (Δ) filling pressures or (Δ) static volumes and (Δ) CI.

Figure 1

Figure 2

Figure 3

Table 1

Conclusion

Filling pressures and static volumes are unreliable preload indices. The EF corrected target volumes better predict fluid responsiveness. We suggest using RVEDVi-C and GEDVi-C as target resuscitation or restoration of organ perfusion endpoints. Unneccessary over-resuscitation past these values will not benefit the patient.