The Identical External Reference Point Standardized to the Zero-Reference Level for Measuring Both Central and...

Area of Science:

• Cardiovascular Physiology
• Medical Measurement Techniques
• Clinical Hemodynamics

Background:

• Discrepancies exist between central venous pressure (CVP) and jugular venous pressure (JVP) measurements.
• The mid-thoracic plane (MTP) is the zero-reference level (ZRL) for venous pressure, while the midaxillary line (MAL) is a common reference in the supine position.
• Traditional JVP measurements use the sternal angle plus 5 cm, and CVP is measured from MAL in the supine position.

Purpose of the Study:

• To compare CVP measured from MTP (CVP-MTP) with CVP measured from MAL (CVP-MAL).
• To compare JVP measured from MTP (JVP-MTP) and sternal angle plus 5 cm (JVP-SA+5).
• To evaluate the agreement between CVP and JVP measurements using MTP as a common reference point.

Main Methods:

• 150 patients underwent blind measurements of JVP-MTP, JVP-SA+5, CVP-MTP, and CVP-MAL.
• Measurements were taken in appropriate reclining positions for JVP and supine for CVP.
• Pearson correlation and Bland-Altman plots were used for pressure comparisons.

Main Results:

• CVP-MTP and CVP-MAL showed similar means, strong positive linear relationships (r=0.908), and good agreement.
• JVP-MTP was significantly higher than JVP-SA+5 (p < 0.001).
• JVP-MTP demonstrated better correlation and agreement with both CVP measurements compared to JVP-SA+5.

Conclusions:

• JVP measurements correlate better with CVP when both are referenced from MTP.
• MAL can serve as a practical reference for CVP measurement in the supine position.
• Standardizing measurements from identical external reference points, like MTP, is crucial for accurate CVP and JVP comparison.