TO MEASURE CVP
1.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.
Rationale: 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.
2.Position the zero point of the manometer at the level of the right atrium.
Rationale: All personal taking the CVP measurement use the same zero point.
3.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.
4.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.
Rationale: 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.i
5.The CVP my range from 5-12cm. HOH.
Rationale: 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.
6.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.
Rationale: CVP is interpreted by considering the patient’s entire clinical picture, hourly urine output, heart rate, blood pressure, cardiac output measurements.
a A CVP zero indicates that patient is hypovolemia (verified if rapid infusion causes patient to improve)
b.A CVP above 15-20cm. HOH may be due to either hypervolemic or poor cardiac contractility.
7.Turn the stopcock again to allow IV solution to flow from solution bottle into the patient’s veins.
Rationale: When readings are not being made, flow is from a very slow microdrip to the catheter, by-passing the manometer.