HWN Suggests

Central Venous Pressure (CVP) in the ICU: Does it predict fluid responsiveness? Nope.

Dinosaurs still roam the earth, I know this. They are slowly and surely retiring, though. I trained in the days where Manny Rivers and the Surviving Sepsis Campaigns pushed for Early-Goal Directed Therapy were king. Hey, there was a reason why it was so successful, EGDT decreased in-hospital mortality from 46.5% to 30.5% in that single centered study where the patients were watched over like hawks, etc. I’m not here to take apart that study. I am not also not saying that Central Venous Pressure (CVP) is useless. It does have its uses such as trending in certain patient populations such as those in the CVICU. But one should never use the isolated value to determine management of the patient. Even…

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 Why do we bother to check CVP?

The use of CVP is largely cultural and deeply ingrained. There are some limited ways and pathologies in which it can be useful, but not as a measure of preload. My friend Paul Marik published a piece that was both enlightening and entertaining in Chest a couple of years ago which I would have thought would have been the final nail in the coffin for the use of CVP as a preload tool, but it endures...even in the latest surviving sepsis guidelines... A testament to religion over science.

 Why should we continue measuring central venous pressure?

Central venous pressure (CVP) is still the most frequent hemodynamic variable for deciding when to administer fluids. This is interesting regarding numerous trials demonstrating that CVP is not a reliable index for predicting fluid responsiveness, and most of the clinical guidelines in which CVP is no longer recommended for such a purpose. Despite its current discredit, should we exclude CVP from our usual hemodynamic evaluation? Or does it still bring relevant information for the patient assessment? Following, we will describe some principles (Table 1) that might be useful for a correct interpretation of CVP measurements from its physiological meaning to its clinical use.

Articles of Interest

Understanding central venous pressure: not a preload index?

The clinical range of CVP values is small and thus the measurement must be made carefully and consistently, especially leveling. This is essential when CVP is trended over time. CVP may not give a precise measure of the preload of the heart and in isolation does not give much information but a high CVP always is abnormal. When taken in the context of the whole clinical picture, CVP can be very helpful diagnostically. It is most helpful when it is used to follow patients over time, especially when there is simultaneous measurement of cardiac output, for this allows one to determine whether the primary change is because of a change in cardiac function or of a change in return function.

Central venous pressure measurement

In a supine patient, there is a reasonably equal distribution of central venous blood throughout the central venous volume. Not so if your patient is upright. The inferior vena cava ends up at the bottom of a column of blood, and the superior vena cava ends up at the top.

Pitfalls in Using Central Venous Pressure as a Marker of Fluid Responsiveness

Although multiple approaches exist to estimate volume status and response in the critically ill patient, no gold standard has yet been established.

Ultrasound based estimate of central venous pressure: Are we any closer?

While pulmonary artery catheterization and central venous catheter obtained measurements are considered to be more accurate, they carry risk of complications and their usage has not shown clinical improvement. Ultrasound-based assessment of the internal jugular vein (IJV) offers real-time, non-invasive measurement of static and dynamic parameters for estimating CVP.

Value of Central Venous Pressure Monitoring in the Patients with Sepsis-Associated Acute Kidney Injury

These findings suggest that CVP measurement alone has little effect on the outcome of septic AKI. Nonetheless, initial CVP levels and the dynamic changes in CVP within the first 48 hours after ICU admission and the mean perfusion pressure initial can improve the accuracy of outcome prediction models.

Resources

CVP Measurement

CVP monitoring in the critically ill is established practice but the traditional belief that CVP reflects ventricular preload and predicts fluid responsiveness has been challenged by a large body of evidence

Cardiovascular Physiology Concepts

The term "central venous pressure" (CVP) describes the pressure in the thoracic vena cava near the right atrium (therefore CVP and right atrial pressure are essentially the same). CVP is an important concept in clinical cardiology because it is a major determinant of the filling pressure and therefore the preload of the right ventricle, which regulates stroke volume through the Frank-Starling mechanism.