Having a therapeutic venesection

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What is this information about?

This information is about a procedure called a therapeutic venesection. This is when some blood (usually 450mls, the same as around two teacups) is taken from a vein. It is used as a treatment for some blood conditions. 

It explains:

• how therapeutic venesection can help you
• which conditions therapeutic venesection can be used to treat
• how many times you may have to have venesections
• where you will have it done
• what you need to do to get ready for having it done
• how the venesection is done and how long it takes
• the side effects of venesection
• how you can get further information or support

Why have I been given this information?

You have been given this information because you have a condition that can be treated by venesection.

How can a therapeutic venesection help treat my condition?

• venesection is a simple and safe way of reducing the number of red blood cells in your blood
• it reduces iron levels or the thickness of the blood to safe levels.

What conditions are treated with therapeutic venesection?

Haemochromatosis

This is a genetic condition where your body takes in too much iron. This is stored in organs around your body such as the heart and liver. This can lead to problems or damage to the organs.

Large amounts of iron are held in red blood cells. The simplest way to remove iron is to take blood from you regularly.

Polycythaemia Vera, erythrocytosis and high haemoglobins

In these conditions you have an increased number of red blood cells. These thicken your blood and make the blood flow more slowly.

This increases the chance of having problems such as a thrombosis (blood clot). Removing the extra red blood cells reduces the chances of this happening.

Transfusion related iron overload

When you are having regular blood transfusions you will be getting more iron than your body needs. Some people may need regular blood transfusions to manage their condition.

When you have blood transfusions often, iron builds up in your tissues, blood, and organs to a level where it can be harmful. Removing the extra red blood cells is one way of dealing with this condition.

Are there any alternatives to venesection?

Yes, but your doctor has recommended venesection as the best way to treat you. If you would like further information on other treatments do speak to your doctor.

How many venesections will I need?

This will be different for each person. It depends on your condition and your blood counts (how many red blood cells you have).

If your blood counts are very high, you may need a venesection every week. This is more likely at the start of your treatment. When they are lower it may be every month and when they are stable it may be every two to six months. Once your condition is under control you may need to come less often.

You may need therapeutic venesections for a short time or over many years.

How long is my venesection likely to take?

You are likely to be at the hospital for about an hour. The venesection takes about 15 minutes. You will need to stay in the Day Unit for a short while afterwards. This is so that we can make sure your blood pressure is stable and you feel well. You may start to feel dizzy or light-headed after your first venesection.

Is there anything I need to do to prepare for the venesection?

• Make sure you arrange transport to go home safely. We recommend that you do not drive yourself when you come to hospital for your first venesection treatment or straight after a venesection as you may have a delayed faint.
• Tell us if you are taking tablets to control your blood pressure. We may ask you not to take them on your first visit.
• We recommend that you have something to eat and drink before coming for your venesection.
• You can usually continue with normal activities before and after the procedure.
• As with any hospital visit you may feel anxious. You can bring someone with you to keep you company if you like.

Is having a venesection painful?

You may feel some discomfort when the needle is put into your arm, but it should not be painful. If it feels too uncomfortable, please tell the nurse who is doing your venesection.

How long does a venesection take?

Collecting your blood takes about 15 minutes.

After that we will offer you a drink and ask you to stay in the day unit for around 20 minutes. You may need to stay longer if there are any problems such as you are feeling light-headed.

How is a venesection done?

Before your first venesection is carried out, your doctor or specialist nurse will explain what will happen.

A nurse, or trained healthcare professional, stays with you when you are having your venesection.

Having a venesection is like donating blood.

1. A tourniquet (tight strap) is put around your arm in the same way as if you were having a blood sample taken.
2. A needle, which is already fixed to the blood collection bag, is put into your vein. This is left fixed in place with tape throughout the collection. It is taken out when your venesection is finished.
3. Pressure is applied where the needle was put in for a few minutes and a small dressing put on. 

Some people may need to be given extra fluids whilst having a venesection. This will be given by an intravenous drip in a vein in the opposite arm. Your doctor may ask for you to have this if you have had low blood pressure or have felt light-headed or faint during or after a venesection.

How might I feel after I have had my venesection?

Most people can do the things that they usually would when they leave the unit after their venesection.

Some people can feel slightly more tired than usual for a couple of days afterwards.

What do I need to do after I have had my venesection?

After your venesection:

Are there any risks or side-effects associated with venesection?

Light-headedness or fainting

Sometimes people can feel light-headed, dizzy or have blurred vision when they are having a venesection or shortly after it. If this happens do tell your nurse straight away.

Rest for a short while after the venesection and have something to eat and drink before the venesection to help to prevent feeling these side effects.

Bruising

You may have a bruise where the needle has been put into your arm. This will disappear after a few days.

Avoid lifting heavy things with this arm for 24 hours after your venesection.

Bleeding from the place where the needle was put in

After the nurse takes the needle out, they will apply pressure to the site and put a dry dressing over it.

Sometimes the site can start to bleed after you have left the day unit. If this happens, please apply pressure directly onto the site until this has stopped.

If the bleeding continues, please call the day unit or go to your nearest accident and emergency department.

If you are taking tablets that thin the blood, for example Warfarin, we may ask you to stay a little longer to check there is no bleeding before you leave the unit.

Anaemia

If you are having venesections, you may become anaemic. Anaemia is when your blood cannot carry the full amount of oxygen around your body because you have less of a substance called haemoglobin.  

This can make you feel tired or faint and cause headaches and breathlessness. If you do get anaemia, you may need treatment for it. This can delay further venesections.

Scarring from long-term needle insertions

We will try not to use the same vein each time. This means there is less chance that you will get long-term scarring at the sites where the needle is put in, but often this cannot be avoided. Your nurse will speak with you about which veins are the best to use for your venesections.

Frequently asked questions (FAQs)

Can I return to work after my venesection?

You can usually return to work after your venesection.

Do not return to work if you feel faint or light-headed. Please discuss this with your doctor or specialist nurse.

Do tell your employer that you are returning to work following venesection treatment. There is a small chance of delayed fainting which could cause harm to you and others around you.

Should I avoid alcohol on the day before and on the day of my venesection?

Yes. Alcohol can:

• cause dehydration. Dehydration should be avoided, particularly before your venesection  
• increase the chance that you will get bruising or bleeding after your venesection

Do avoid alcohol on the day before and the day of your venesection.

Can the blood taken out when I have my venesection be donated?

No. Although venesection is similar to giving a blood donation, we cannot use the blood we collect in a venesection for donation. It is always disposed of.

If you would like to be a volunteer blood donor details can be found on the Give Blood website. You can discuss this with your doctor. There are some conditions which, if you have them, mean you cannot donate blood.

Do tell us at your next venesection clinic visit if you do donate blood. We need to keep a record of how much blood is being taken.

Where can I get further information or advice if I need it after I have read this information?

Please speak to your doctor at your next appointment.

Do not hesitate to ask if you have any questions or worries or would like more information about the condition you have or venesection. We will be more than happy to help.

It may help to make a note of any questions that you want to ask.

How can I contact the treatment centre?