A PATIENT'S GUIDE TO PHLEBOTOMY
This information answers some common questions about the use of phlebotomy in the treatment of cyanotic congenital heart disease.
What is a phlebotomy?
A phlebotomy is a safe outpatient procedure in which a predetermined amount of blood (usually half a litre or 16 ounces) is removed while at the same time a predetermined amount of intravenous fluid is administered (volume replacement) using normal saline (a weak solution of salt and water).
Why is phlebotomy needed?
Red blood cells (RBCs) pick up oxygen from the lungs and deliver it to the body. With cyanotic congenital heart disease not enough oxygen enters the blood. The body then increases production of RBCs in an attempt to compensate. This condition is called erythrocytosis. As the number of RBCs increase, the blood becomes thicker and may cause symptoms of fatigue, dizziness, headaches, faintness, decreased alertness, blurred or double vision, muscle aches, numbness and tingling in the fingers, toes, or lips, or ringing in the ears. The goal of the phlebotomy is to relieve these symptoms. Interestingly, each person will develop his/her own symptoms that can be different from someone elseís. Your doctor will monitor your bloodwork looking specifically at your hemoglobin and hematocrit (values on your bloodwork that represent the number of RBCs in the blood).
What other concerns are there when having a phlebotomy?
Before having a phlebotomy, careful discussions should take place between you and your physician to rule out other causes of symptoms. A phlebotomy is not recommended if you are iron deficient or if your blood count is too high because you were dehydrated. Both of these concerns should be corrected before considering a phlebotomy. A phlebotomy is not done to prevent cerebrovascular events (stroke). In fact, inappropriate phlebotomies can cause iron deficiency, worsen your symptoms and actually increase your risk of stroke. If you do not have symptoms like those above that are interfering with your daily activities you do not need a phlebotomy, even if your hemoglobin and hematocrit are high.
How is phlebotomy performed?
A phlebotomy is performed as an outpatient at the hospital or at your cardiologistís office. Under the direction of your cardiologist, laboratory or nursing staff performs the phlebotomy. An intravenous (IV) needle is inserted into a vein in your hand or arm to deliver IV fluid (a weak solution of salt and water). A second needle is inserted to remove the blood. The amount of blood removed varies and is determined by your cardiologist. The phlebotomy takes approximately thirty minutes. During this time the nurse will check your heart rate and blood pressure. Once finished, the needles are removed and you are observed until you are felt to be well enough to leave.
Are there any side effects?
Side effects are very uncommon. There is minor discomfort associated with the insertion of the needles. This may cause some people to feel faint, nauseated, or sweaty. After the phlebotomy you may experience dizziness and a feeling of being tired. These feelings can last a day or two. Your iron stores may become depleted if periodic phlebotomies are necessary. Iron deficiency must be avoided. Your doctor will monitor your iron levels and may prescribe an iron supplement. If you suffer from side effects of oral iron supplements, replacement with iron that is administered through an IV can be considered.
Is there any preparation required?
There is no preparation necessary for a phlebotomy. You may eat a normal diet and take your medications. However, as you might feel tired or somewhat dizzy after the phlebotomy, you might want a family member or friend to accompany you home.
How soon should a benefit be felt?
The time will vary from one person to another, but relief of symptoms should begin to occur within a few days of getting your hemoglobin suitably reduced (this may take more than one phlebotomy if your hemoglobin was very high). The oxygen delivery to your tissues is improved which can lead to an increase in exercise performance.
How often is a phlebotomy required?
This varies from person to person. It all depends on when your symptoms return. Usually you will be troubled by the same symptoms when your hemoglobin and hematocrit become too high. A phlebotomy can be repeated as soon as 48 hours after your previous phlebotomy if you are not iron deficient or dehydrated. Your doctor will monitor your hemoglobin and hematocrit through regular blood samples, however the best indicator of your need for a phlebotomy is the return of your symptoms.
What can you do?
This information has been provided by the staff of the Adult Congenital Heart Disease Clinic at the Peter Lougheed Centre Calgary, Alberta.