Bedside assessment and clinical utility of mean systemic filling pressure in acute care

The bed-side monitoring of patients with acute and complex perturbations in cardiocirculatory function focusses predominantly on the arterial, delivery side of the circulation. Yet, as cardiac output equals venous return under steady state conditions, an adequate cardiac output is highly dependent on the venous side of the circulation. The mean systemic filling pressure (Pmsf), which equals overall intravascular pressure under zero flow conditions, is the upstream pressure for venous return and is a quantitative index of intravascular blood volume and vascular tone. Nowadays, Pmsf can be estimated indirectly at the bed-side, allowing to track changes in Pmsf, for example during the administration of fluids and vasoactive agents. It has not been proven as of yet that guiding hemodynamic management by Pmsf directly benefits patient outcome. Nevertheless, Pmsf monitoring provides an excellent opportunity to “characterize” the physiological response to hemodynamic interventions other than solely looking at arterial blood pressure and cardiac output. Therefore, Pmsf monitoring might be an important tool for improving our knowledge on hemodynamic functioning in acutely ill patients, and its use in future (outcome-related) studies should be encouraged.