What does central venous pressure (CVP) predominantly measure?

Central venous pressure (CVP) predominantly measures right atrial filling pressure and volume status. It reflects the pressure within the thoracic vena cava near the right atrium, which provides critical information about the patient's hemodynamics. This measurement is essential for assessing the heart's ability to manage blood returning to it, indicating the volume status of a patient and helping to identify conditions such as hypovolemia or fluid overload.

CVP is influenced by various factors, including blood volume, venous tone, and the ability of the right heart to pump effectively. When there's sufficient blood volume returning to the heart, CVP levels rise; conversely, they decrease in states of hypovolemia. Thus, monitoring CVP allows clinicians to infer the fluid status of a patient and make informed decisions regarding fluid management, especially in critically ill patients.

The other answers relate to different aspects of cardiovascular physiology and hemodynamics but do not directly assess the right atrial filling pressure or overall fluid status. For example, systemic vascular resistance pertains more to the afterload faced by the heart, while left ventricular ejection fraction measures the heart's pumping efficiency rather than filling pressures. Pulmonary artery pressure assesses pressures within the pulmonary circulation, which, while related to right