INTERPRETING CENTRAL VENOUS PRESSURE WAVEFORMS IN TERPRETING CEN TRAL VEN OUS PRESSURE W AVEFORMS INTRODUCTION A central venous pressure waveform provides important information about the hemodynamic state of the patient and compliance of the syste m. - CENTRAL VEN OUS PRESSURE (CVP) W AVEFORMS • Measures pressure in the central venous circulation • Obtained by using a central venous catheter ideally placed at the junction of the superior vena cava (SVC) and the right atrium • Depends on: 1. Compliance of the cardiovascular system 2. Overall volume status Figure 1: Central venou s catheter placement at the SV C-RA junction INTERPRETING CVP W AVEFORMS Remember that the waveform represents atrial pressure which is the relationship between atrial compliance and volume. One CVP Waveform represents one complete beat of the heart. • a-wave: atrial contraction • Corresponds with timing of P wave on ECG • Noncompliant right atrium: = large a-wave • c-wave: movement of the tric uspid valve into the right atrium • Corresponds with timing of R wave on ECG • Transient decrease in atrial compliance/increase in atrial pressure • c-wave and a-wave can be difficult to differentiate when patient is ta tachycardic • x-descent: atrial relaxation • Corresponds with timing of QRS complex on ECG Figure 2: The different parts of a central venous • Tricuspid valve descends towards the apex of the right ventricle pressure waveform causing a decrease in right atrial pressure • v-wave: atrial filling • Corresponds with timing of T wave on ECG • A large v-wave may indicate tricuspid regurgitation QRS • If right atrium is very compliant, tricuspid regurgitation is possible complex without generation of large v-wave • y-descent: atrial emptying • Corresponds with timing just prior to P wave on ECG P wave T wave Figure 3: ECG showing timing of CVP waveform components This document is meant to be used as an educational resource for physicians and other healthcare professionals. It is in no way a substitute for the independent decision making and judgment by a qualified health care professional. Users of this guideline assume full responsibility for utilizing the information contained in this guideline. OPENPediatrics™ and its affiliations are not responsible or liable for any claim, loss, or damage resulting from the use of this information. OPENPediatrics™ attempts to keep the information as accurate and up to date as possible. However, as recommendations for care and treatment change, OPENPediatrics™ does not assume any legal liability or responsibility for the accuracy, completeness or usefulness of any information on this guideline. CPAP PAGE 1 of 1 .