New Era University College of Nursing
Central Venous Pressure Monitoring NCM-RLE 104
Submitted To: Prof. Anelita Dela Cruz
Submitted By: John Erlan S. Lipata
SY. 2010-11
Central Venous Pressure Monitoring The CVP, the pressure in the vena cava or right atrium, is used to assess right ventricular function and venous blood return to the right side of the heart. The CVP can be continuously measured by connecting either a catheter positioned in the vena cava or the proximal port of a pulmonary artery catheter to a pressure monitoring system. The pulmonary artery catheter, described in greater detail later, is used for critically ill patients. Patients in general medical-surgical units who require CVP monitoring may have a single-lumen or multilumen catheter placed into the superior vena cava. Intermittent measurement of the CVP can then be obtained with the use of a water manometer. Because the pressures in the right atrium and right ventricle are equal at the end of diastole (0 to 8 mm Hg), the CVP is also an indirect method of determining right ventricular filling pressure (preload). This makes the CVP a useful hemodynamic parameter to observe when m anaging an unstable patient¶s fluid v olume status. A rising pressure may be caused by hypervolemia or by a condition, such as HF , that results in a decrease in myocardial contractility . Pulmonary artery monitoring is preferred for the patient with HF. Decreased CVP indicates reduced right ventricular preload, most often caused by hypovolemia. This diagnosis can be substantiated when a rapid intravenous infusion causes the CVP to rise. (CVP monitoring is not clinically useful in a patient with HF in whom left ventricular failure precedes right ventricular failure, because in these patients an elevated CVP is a very late sign of HF.) Before insertion of a CVP catheter, the site is prepared by shaving if necessary and by cleansing with an antiseptic solution. A local anesthetic may be used. The physician threads a singlelumen or multilumen catheter through the external jugular, antecubital, or femoral vein into the vena cava just above or within the right atrium.
Conditions which cause the CVP to Ris e:
will cause the CVP to be higher than normal. This will happen when a patient has been intubated and is being v entilated artificially. Whenever there is impaired cardiac function (right sided heart failure, tamponade) the CVP will rise Hypervolemia happens when a patient has been given an excess amount of IV fluids. This will cause the CVP to rise. It is for this reason that physicians often prescribe fruosemide to patients when giving packed red blood cells. The RBCs increase circulating volume and the fruosemide decreases it. Homeostasis is maintained. O bstruction of the superior vena cava will cause the CVP to ri se P ulmonary artery stenosis which limit venous outflow and lead to venous congestion cause the CVP to rise S training, forced exhalation, tension pneumothorax and pleural effusion will cause CVP to rise I ncreased intra-thoracic pressure
Conditions which cause the CVP to Decrease:
Hypovolaemia is a decrease in circulating volume. These conditions include blood loss and excessive diuresis. Reduced intra-thoracic pressure as seen during inspiration
NURSING INTERVENTIONS y y
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Once the CVP catheter is inserted, it is secured and a dry, sterile dressing is applied. Catheter placement is confirmed by a chest x-ray, and the site i s inspected daily for signs of infection. The dressing and pressure monitoring system or water manometer are changed according to hospital policy. In general, the dressing is to be kept dry and air occlusive. Dressing changes are performed with the use of sterile technique. CVP catheters can be used for infusing intravenous fluids, administering intravenous medications, and drawing blood specimens in addition to monitoring pressure. To measure the CVP, the transducer (when a pressure monitoring system is used) or the zero mark on the manometer (when a water manometer is used) must be placed at a standard reference point, called the phlebostatic axis. After locating this position, the nurse may make an ink mark on the patient¶s chest to indicate the location. If the phlebostatic axis isnused, CVP can be measured correctly with the patient supine at any backrest position up to 45 degrees. The range for a normal CVP is 0 to 8 mm Hg with a pressure monitoring system or 3 to 8 cm H 2 O with a water manometer system. The most common complications of CVP monitoring are infection and air embolism.
The Phlebostatic Axis and the Phlebostatic Level
(A) The phlebostatic axis is the crossing of two reference lines: (1) a line from the fourth intercostal space at the point where it joins the sternum, drawn out to the side of the body beneath the axilla; and (2) a line midway between the anterior and posterior surfaces of the chest. (B) The phlebostatic level is a horizontal line through the phlebostatic axis. The air±fluid interface of the stopcock of the transducer, or t he zero mark on the manometer, must be level with this axis for accurate measurements. When moving from the flat to erect positions, the patient moves the chest and therefore the reference level; the phlebostatic level stays horizontal through the same reference point. (C) Two methods for referencing the pressure system to the phlebostatic axis. The system can be referenced by placing the air±fluid interface of either the in-line stopcock or stopcock on top of the transducer at the phlebostatic level.
References:
http://healthmad.com/nursing/central-venous-pressure/ Smeltzer and Bare 2004, ³Medical- Surgical Nursing´, Lipincot Williams & Wilkins, 10th edition nd Williams and Hooper 2003, ³Understanding Medical Surgical Nursing´ F. A. Davis Company, 2 edition
