Norm of Blood Volume Determination Studies
Usage of Blood Volume Determination Studies
Differential diagnosis of pericardial effusion from pericardial cysts or tumors, diagnosis of peripheral vascular disease, and thrombophlebitis.
Description of Blood Volume Determination Studies
A nuclear medicine study of circulation dynamics in which a tracer is circulated in the blood for a period of time. Measures of diluted radioactivity are used to calculate the volume distribution of compartments and regions of the circulation. Pericardial effusions are detected by examination of the blood volumes in and around the heart. Peripheral vascular disease and thrombophlebitis are detected by examination of the rates at which the venous pools of the legs change in volume with exercise and posture changes.
Professional Considerations of Blood Volume Determination Studies
Consent form IS required.
Allergic reaction to radiolabeled albumin (itching, hives, rash, tight feeling in the throat, shortness of breath, bronchospasm, anaphylaxis, death), hematoma, or infection at injection site.
Previous allergy to iodine, radiographic dye, seafood, or a nuclear medicine radiolabeled albumin tracer.
During pregnancy, risks of cumulative radiation exposure to the fetus from this and other previous or future imaging studies must be weighed against the benefits of the procedure. Although formal limits for client exposure are relative to this risk-benefit comparison, the United States Nuclear Regulatory Commission requires that the cumulative dose equivalent to an embryo/ fetus from occupational exposure not exceed 0.5 rem (5 mSv). Radiation dose to the fetus is proportional to the distance of the anatomy studied from the abdomen and decreases as pregnancy progresses. For pregnant clients, consult the radiologist/radiology department to obtain estimated fetal radiation exposure from this procedure.
- Have emergency equipment readily available.
- Establish intravenous access in an arm vein.
- Just before beginning the procedure, take a “time out” to verify the correct client, procedure, and site.
- A tracer of labeled albumin, red blood cells, or substances bound by plasma proteins is injected intravenously and allowed to circulate. The circulatory compartment to be studied is scanned, and a scintillation well counter is used to compare the diluted radioactivity of the compartment with a standard. This is followed by calculation of the volume distribution of the compartment.
- Encourage the oral intake of fluids.
Client and Family Teaching
- The risk of radioactivity from this test is less than that of a regular radiograph.
Factors That Affect Results
- Blood volume is highest in the morning.
- No isolation of the client is necessary.
- Health care professionals working in a nuclear medicine area must follow federal standards set by the Nuclear Regulatory Commission. These standards include precautions for handling the radioactive material and monitoring of potential radiation exposure.