From the Guidelines
Central venous pressure (CVP) is not measured on the ECG portion of an ICU monitor, but rather through a separate waveform display connected to a central venous catheter.
Measuring CVP
To measure CVP accurately, you should identify the end-expiratory point on the waveform (when intrathoracic pressure effects are minimized) and measure the mean pressure at that point. Some key points to consider when measuring CVP include:
- Normal CVP values range from 2-6 mmHg 1
- CVP measurement helps assess right heart function, volume status, and response to fluid therapy
- The ECG, in contrast, displays electrical activity of the heart and cannot provide pressure measurements
- Most ICU monitors display these as separate parameters, with CVP appearing alongside other hemodynamic measurements like arterial blood pressure
Clinical Context
In the context of ICU care for patients with pulmonary arterial hypertension (PAH), CVP measurement is crucial for assessing volume status and guiding fluid therapy, as noted in the management of critically ill PAH patients 1.
Key Considerations
Some key considerations when interpreting CVP measurements include:
- The potential for non-invasive estimates of central venous pressures to be misleading 1
- The importance of maintaining systemic vascular resistance (SVR) greater than pulmonary vascular resistance (PVR) in PAH patients 1
- The use of inotropes and vasopressors, such as dobutamine and epinephrine, to support right heart function in PAH patients 1
From the Research
Measuring Central Venous Pressure (CVP) on ICU Monitor
To measure CVP on an ICU monitor, it is essential to understand the proper techniques and features of the waveform. The following points highlight the key aspects of CVP measurement:
- CVP is typically measured using a central venous catheter (CVC) positioned in the right atrium or superior or inferior vena cava as close to the right atrium as possible 2.
- The CVC is usually inserted via the internal jugular vein, subclavian vein, or femoral vein, depending on the patient and their condition 2.
- The proper use of CVP requires a good understanding of basic measurement techniques and features of the waveform, including leveling of the transducer and consideration of transmural pressure 3.
- Examining the waveforms of the CVP tracing can provide valuable information, such as rhythm disorders, tricuspid regurgitation, cardiac tamponade, cardiac restriction, and decreased thoracic compliance 3.
ECG and CVP Measurement
Regarding the specific part of the ECG to measure CVP on an ICU monitor, there is no direct evidence to suggest that CVP is measured on the ECG itself. However, CVP is often used in conjunction with ECG monitoring to assess cardiac function and guide fluid resuscitation in critically ill patients 4, 2, 5.
- CVP can be estimated using echocardiography, such as Doppler recognition of low or normal central venous pressure from continuous flow from the inferior vena cava into the right atrium 6.