Positive pressure ventilation influences venous return primarily by increasing right atrial pressure, which reduces the venous return driving pressure, while its effects on mean systemic filling pressure remain debated.
Venous return, i.e., the blood flowing back to the heart, is driven by the pressure difference between mean systemic filling pressure and right atrial pressure (RAP). Besides cardiac function, it is the major determinant of cardiac output. Mean systemic filling pressure is a function of the vascular volume. The concept of venous return has a central role for heart lung interactions and the explanation of shock states. Mechanical ventilation during anaesthesia and critical illness may severely affect venous return by different mechanisms. In the first part of the following article, we will discuss the development of the concept of venous return, its specific components mean systemic and mean circulatory filling pressure (MCFP), RAP and resistance to venous return (RVR). We show how these pressures relate to the volume state of the circulation. Various interpretations and critiques are elucidated. In the second part, we focus on the impact of positive pressure ventilation on venous return and its components, including latest results from latest research.
Berger et al. (Sat,) conducted a review in Hemodynamics and mechanical ventilation. Positive pressure ventilation was evaluated. Positive pressure ventilation influences venous return primarily by increasing right atrial pressure, which reduces the venous return driving pressure, while its effects on mean systemic filling pressure remain debated.