Right Atrial Pressure in the Critically Ill: How to Measure, What Is the Value, What Are the Limitations?
Right atrial pressure (Pra) is determined by the interaction of the function of the heart as a pump, which is called cardiac function, and the factors that determine the return of blood to the heart, which is called return function. Thus, monitoring Pra or its surrogate, central venous pressure (CVP), can give important insights into mechanisms behind changes in hemodynamic status, responses to interventions, and the likelihood of diagnoses. Examination of the components of the Pra tracing, especially during the ventilator cycle, can also give information about right-sided cardiac diastolic function, the status of the tricuspid valve, volume responsiveness, and the cardiac rhythm. Importantly, the pressure difference from the large venous reservoir to the heart is small, and thus great care must be taken with technical factors that affect the measurement.