BACKGROUND:

Dissociation between macrocirculation and microcirculation is often observed in surgical patients.

OBJECTIVE:

To test the hypothesis that the analogue of mean circulatory filling pressure (Pmca) can monitor hemodynamic coherence during major non-cardiac surgery.

METHODS:

In this post-hoc analysis and proof-of-concept study, we used the central venous pressure (CVP), mean arterial pressure (MAP), and cardiac output (CO) to calculate Pmca. Efficiency of the heart (Eh), arterial resistance (R_art), effective arterial elastance (E_a), venous compartment resistance (R_ven), oxygen delivery (DO₂), and oxygen extraction ratio (O₂ER) were also calculated. Sublingual microcirculation was assessed using SDF + imaging, and the De Backer score, Consensus Proportion of Perfused Vessels (Consensus PPV), and Consensus PPV (small) were determined.

RESULTS:

Thirteen patients were included, with a median age of 66 years. Median Pmca was 16 (14.9–18) mmHg and was positively associated with CO [p < 0.001; a 1 mmHg increase in Pmca increases CO by 0.73 L min^-1 (p < 0.001)], Eh (p < 0.001), R_art (p = 0.01), E_a (p = 0.03), R_ven (p = 0.005), DO₂ (p = 0.03), and O₂ER (p = 0.02). A significant correlation was observed between Pmca and Consensus PPV (p = 0.02), but not with De Backer Score (p = 0.34) or Consensus PPV (small) (p = 0.1).

CONCLUSION:

Significant associations exist between Pmca and several hemodynamic and metabolic variables including Consensus PPV. Adequately powered studies should determine whether Pmca can provide real-time information on hemodynamic coherence.