11. CVP BLOOD VOLUME (INCREASED VENOUS RETURN RAISES CVP CARDIAC COMPETENCE (REDUCED VENTRICULAR FUNCTION RAISES CVP) INTRATHORACIC AND INTRAPERITONEAL PRESSURE (RAISES CVP) SYSTEMIC VASCULAR RESISTENCE (INCREASED TONE RAISES CVP)
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31. EQUIPMENT IV extension set to entry port of patients central line. IV giving set to fluid bag. Stopcock (Three way tap)
32. DIRECTION OF FLOW The white arrows indicate the direction of fluid flow. (a). Initially the white knob is turned straight up, allowing fluid to flow from the fluid bag to the patient's catheter to assure the catheter is patent.. If fluid does not flow freely into the patient's catheter a valid CVP reading will not be obtained. (b) Then the knob is turned toward the patient and fluid will fill the manometer. The manometer should not contain any air bubbles . If air is present in the manometer or fluid line, let the fluids run, overfilling the manometer until all air is purged from the system. (c) Then turn the knob toward the fluids. The level of fluid in the manometer will fall (the fluid is running into the patient's catheter) until the height of the fluid column exerts a pressure equivalent to the patient's CVP The top of the fluid column will slightly oscillate up and down as the pt’s heart beats and as the pt breathes. a. c. b.
33. POSITION OF PATIENT 3-way tap manometer Fluid Bag Patient in supine position Central Venous Access
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45. M marks the appropriate place for measurement. The bottom tracing shows the overlap tracing with pulmonary artery pressure (PAP). This also can be used for timing the end of diastole and the place to make the measurement. shows a tracing from a young woman who had a major bleed following a hysterectomy
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47. This indicates severe TR. It must be appreciated that the peak of the v wave, which is 35 mmHg, will still have an important impact on upstream structures such as the liver and kidney
A wave: right atrial contraction (P wave on the ECG) If the A wave is elevated the patient may have right ventricular failure or tricuspid stenosis. C wave: tricuspid valve closure (follows QRS complex on the ECG). V wave: pressure generated to the right atrium during ventricular contraction, despite the tricuspid valve being closed (latter part of the T wave on the ECG)
Transparent dressings should be used to permit continuous monitoring of the site. If infection of the CVP line is suspected blood cultures should be taken following removal of the line. The catheter tip should be sent for M C & S.
