Pulmonary Artery Pressure Monitoring
This monitors the pressures in the right side of the heart and indirectly measures the left side of the heart. This is the most invasive catheter used in critical care, and routine use of the pulmonary artery (PA) catheter is controversial; it can assess many hemodynamic parameters such as PA systolic and diastolic, pulmonary MAP, pulmonary artery wedge pressure (PAWP), and cardiac output. Cardiac output is used to calculate other parameters such as cardiac index, systemic vascular resistance (SVR), and pulmonary vascular resistance (PVR). PAWP is also known as pulmonary artery occlusive pressure or pulmonary capillary wedge pressure.
The traditional PA catheter is known as a Swan-Ganz catheter after its inventors, and the thermodilution catheter after the principle behind its operation. The basic catheter has four lumens: RA pressure, PA pressures, PAWP, and cardiac output. There are other versions of this catheter with advanced features, such as additional atria lumens for intravenous infusion, continuous mixed venous oxygen saturation (SvO2), continuous cardiac output monitoring, and pacemaker functions. Before insertion of this catheter, the flush system is connected to the transducer, zeroed, and leveled. The lumens of
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The estimation of preload is based on the assumption that pressure and volume are equated. Therefore, pressures are used to estimate end diastolic volume. Likewise, RA pressure is used to assess end diastolic volume of the RV, and PAWP is used to evaluate left ventricular preload. Afterload is the resistance to ventricular ejection and is influenced by PVR. PVR assesses the right ventricular afterload, and SVR indexed to BSA estimates left ventricular afterload (Morton & Fontaine, 2013). Contractility is not directly determined; however, stroke volume index for right and left ventricles is used to estimate