Description
Central venous pressure (CVP) describes the pressure of blood in the thoracic vena cava, near the right atrium of the heart. CVP reflects the amount of blood returning to the heart and the ability of the heart to pump the blood into the arterial system.
Objectives
- To serve as a guide for fluid replacement in seriously ill patients.
- To estimate blood volume deficits.
- To determine pressures in the right atrium and central veins.
- To evaluate for circulatory failure (in context with total clinical picture of a patient)
Indications
- Patients having Cardiovascular disorders
Nursing Alert: Don’t rely on CVP alone, use them in conjunction with other assessment data. Report abnormal findings to the doctor.
Equipment
- Venous pressure tray
- Cut-down tray
- Infusion solution and infusion set
- 3-way or 4-way stopcock (a pressure transducer may also be used)
- IV pole attached to bed
- Arms board
- Adhesive tape
- ECG monitor
- Carpenter’s level (for establishing zero point)
Nursing Interventions
| Nursing Interventions | Rationale |
| Assemble equipment according to manufacturer’s directions. | |
| Explain that the procedure is similar to an IV and that the patient may move in bed as desired after passage of the CVP catheter. | |
| Place the patient in a position of comfort. This is the baseline used for subsequent readings. | Serial CVP readings should be made with the patient in the same position. Inaccuracies in CVP readings can be produced by changes in positions, coughing, or straining during the reading. |
| Attached manometer to the IV pole. The zero point of the manometer should be on a level with the patient’s right atrium. | The right atrium is at the midaxillary line, which is about 1/3 of the distance from the anterior to the posterior chest wall. |
| Mark the midaxillary line on the patient with an indelible pencil. | The maxillary line is an external reference point for the zero level of the manometer (which coincides with level of the right atrium). |
| The CVP catheter is connected to a 3-way stopcock that communicates to an open IV and to a manometer. | Or, the CVP catheter may be connected to a transducer and an electric monitor CVP wave either digital or calibrated CVP wave read out. |
| Start the IV flow and fill the manometer 10 cm above anticipated reading (or until the level of 20cm, HOH is reached). Turn the stopcock and fill the rubbing with fluid. | |
| The CVP site is surgically cleansed. The physician, introduces the CVP catheter percutaneously or by direct venous cutdown and threaded through an antecubital, subclavian, or internal or external jugular vein into the superior vena cava just before it enters the right atrium. | If the catheter is inserted through the subclavian or internal jugular vein, place patient in a head-down position to increase venous filling and reduced risk of air embolism. The correct catheter placement can be confirmed by fluoroscopy or chest x-ray. |
| When the catheter enters the thorax an inspiratory fall and expiratory rise in venous pressure are observed. | The fluid level fluctuates with respiration. If rises sharply with coughing/straining. |
| The patient may be monitored by ECG during catheter insertion. | When the tip of the catheter contacts the wall of the right atrium it may produce aberrant impulses and disturb cardiac rhythm. |
| The catheter may be sutured and taped in place. A sterile dressing is applied. | Label dressing with time and date of catheter insertion. |
| The infusion is adjusted to flow into the patient’s vein by a slow continuous drip. | The infusion may cause a significant increase in venous pressure if permitted to flow too rapidly. |
Measuring Central Venous Pressure
| Nursing Intervention | Rationale |
| Place the patient in the identified position and confirm zero point. Intravascular pressures are measured to the atmospheric pressure at the middle of the right atrium; this is the zero point or external reference point. | The zero point or baseline for the manometer should be on level with the patient’s right atrium. The middle of the right atrium is the midaxillary line in the 4th intercostals space. |
| Position the zero point of the manometer at the level of the right atrium. | All personal taking the CVP measurement use the same zero point. |
| Turn the stopcock so that the IV solution flows into the manometer filling to about the 20-25cm level. Then turn the stopcock so that the solution in manometer flows into the patient. Observe the fall in the height of the column of fluid in the manometer. Record the level at which the solution stabilizes or stops moving downward. This is the central venous pressure. Record CVP and the position of the patient. |
The column of fluid will fall until it meets an equal pressure (i.e. the patient’s central venous pressure). The reading is reflected by the height of a column of fluid in the manometer when there’s open communication between the catheter and the manometer. The fluid in the manometer will fluctuates slightly with the patient’s respirations. This confirms that the CVP is not obstructed by clotted blood. |
| The CVP my range from 5-12cm. HOH. | The change in CVP is a more useful indication of adequacy of venous blood volume and alterations of cardiovascular function. CVP is a dynamic measurement. The normal values may change from patient to patient. The management of the patient’s not based on one reading but on repeated serial readings in correlation with patient’s clinical status. |
| Assess patient’s clinical condition. Frequent changes in measurements (interpreted within the context of the clinical situation) will serve as a guide to detect whether the heart can handle its fluid load and whether hypovolemia or hypervolemia is present. | CVP is interpreted by considering the patient’s entire clinical picture, hourly urine output, heart rate, blood pressure, cardiac output measurements.
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| Turn the stopcock again to allow IV solution to flow from solution bottle into the patient’s veins. | When readings are not being made, flow is from a very slow microdrip to the catheter, by-passing the manometer. |
Charting
- Location of insertion site
- Type and size of needle or cannula used for insertion
- Time of insertion
- Appearance of needle insertion site
References
- Measuring Central Venous Pressure | anaesthesia.hku.hk