B. Central Venous Pressure Monitoring
Central venous pressure (CVP) is utilized as a surrogate of right atrial
pressure (and correlating with left atrial filling pressure assuming a constant fluid
column). Utilizing pressure as a marker of volume status is subject to multiple
confounding variables (intrathoracic pressure, valvular abnormalities, pulmonary
vascular disease), but is commonly utilized (at a minimum) for following a trend in
volume status. CVP is ideally measured in the SVC but is often measured in the
IVC although the pressures are often not equal. CVP is measured at the end of
diastole (mean value of the a-wave) just prior to tricuspid valve closure and
ventricular ejection) corresponding to RV end diastolic pressure.
FIGURE 2 FUHRMAN FIGURE 21 - 5
C. Central Venous Pressure and Oxygen Saturation Monitoring
Central venous pressure (CVP) is a valuable surrogate measure of right
heart preload. Ideally, the catheter should lie within the right atrium or equivalent
structure and should be a semi-rigid device. Like arterial catheters, these
devices require a zero point and a continuous water column to the transducer. In
distinction from arterial catheters, intrathoracic vascular pressure monitoring
devices are subject to the impact of oscillating thoracic pressure with respiration.