Central venous pressure (CVP) is the pressure measured in the central veins located near the heart. It designates the mean right atrial pressure and is frequently used as a guesstimate of right ventricular preload. “Central venous pressure does not truly measure blood volume, although it is often used to estimate it. The value of central venous pressure is determined by the pressure of the venous blood in the vena cava and the function of the right heart, and is influenced not only by the intravascular volume and venous return, but also by the venous tone and intrathoracic pressure, as well as by the function of the right heart and myocardial compliance” (Department of Anesthesiology, University of Hong Kong, n.d.). Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay "Underfilling and overdistension of the venous collecting system can be recognized by central venous pressure measurements before clinical signs and symptoms become evident". Under normal conditions, an increase in venous return causes an increase in cardiac output, without significant changes in central venous pressure. However, in cases of poor right ventricular function or obstructed pulmonary circulation, right atrial pressure increases, thus causing a subsequent increase in central venous pressure. Similarly, it is possible for a patient with hypovolemia to exhibit central venous pressure in the normal range due to loss of blood volume or widespread vasodilation which will result in reduced venous return and a drop in right atrial pressure and central venous pressure ” (Richard E. Klabunde, 2014).“Central venous pressure can be measured manually using a manometer or electronically using a transducer. In both cases the central venous pressure must be zeroed at the level of the right atrium. This is usually the level of the fourth intercostal space in the midaxillary line while the patient lies in the supine position. Each central venous pressure measurement must be taken at the same zero position. Trends in sequential central venous pressure measurement are much more informative than individual readings. However, if the central venous pressure is measured at a different level each time, this makes the measurement pattern inaccurate” (Department of Anesthesiology, University of Hong Kong, n.d.). Pulmonary artery pressure (PA pressure) is a measurement of blood pressure found in the pulmonary artery of the heart. “Pulmonary artery pressure is generated by the right ventricle expelling blood into the pulmonary circulation, which acts as an opposition to the output by the right ventricle. With each ejection of blood during ventricular systole, the volume of pulmonary arterial blood increases, stretching the artery wall. As the heart relaxes, also known as ventricular diastole, blood continues to flow from the pulmonary artery into the pulmonary circulation. The smaller arteries and arterioles serve as major resistance vessels and, through changes in their diameter, regulate pulmonary vascular resistance” (Richard E. Klabunde, The Pharmacologic Treatment of Pulmonary Hypertension, 2010). Today, pulmonary artery catheters are placed on a case on a case-by-case basis, taking into account the patient's condition and the qualification of the personnel. Conditions for use of a pulmonary catheter include severe cardiogenic pulmonary edema, patients with acute respiratory distress syndrome who are not hemodynamically stable, patients who have undergone thoracic surgery,”