Objective:

To examine the relevance of mean circulatory filling pressure and mean systemic filling pressure in understanding blood return to the heart and venous pressures in critically ill patients.

Key Findings:

• Mean circulatory filling pressure indicates pressure throughout the vascular system if blood flow ceases.
• Mean systemic filling pressure drives blood return to the right atrium and influences cardiac output.
• The pressure gradient between mean systemic filling pressure and right atrial pressure is typically small (3 to 6 mmHg).
• Right atrial pressure measurement is more clinically actionable than estimating mean systemic filling pressure.

Interpretation:

Mean systemic filling pressure, particularly in relation to right atrial pressure, is crucial for understanding venous return dynamics in critically ill patients.

Limitations:

• Proposed bedside techniques to estimate mean systemic filling pressure have limited clinical value.
• The review does not provide new empirical data but synthesizes existing knowledge.

Conclusion:

Mean circulatory filling pressure reflects potential energy in the vascular system, while mean systemic filling pressure and its relationship with right atrial pressure are more relevant for clinical decision-making.