From the Guidelines
Venasection, or phlebotomy, is a medical procedure that involves removing blood from a patient's vein for therapeutic purposes, and the most recent and highest quality evidence recommends using real-time ultrasound guidance for puncture of the vein to minimize complications and ensure success 1. The procedure begins with patient identification and explanation of the process to obtain informed consent. The healthcare provider then positions the patient comfortably, typically in a seated or reclined position, and applies a tourniquet to the upper arm to make veins more visible.
- Key steps in the procedure include:
- Selecting an appropriate vein, usually in the antecubital fossa
- Cleaning the skin with an antiseptic solution such as 70% alcohol
- Using a large-bore needle (typically 16-18 gauge) connected to a collection bag or bottle
- Inserting the needle into the vein at a 15-30 degree angle, using real-time ultrasound guidance to ensure accurate placement 1
- Releasing the tourniquet once blood flow is established, and collecting approximately 350-500 mL of blood over 15-20 minutes
- Throughout the procedure, the patient's vital signs are monitored for signs of vasovagal reactions, and after collecting the desired volume, the needle is removed, and pressure is applied to the puncture site for 2-3 minutes to prevent bleeding.
- A sterile dressing is then applied, and patients are advised to rest for 10-15 minutes afterward, increase fluid intake for the next 24 hours, and avoid strenuous activities for the remainder of the day. The use of ultrasound-guided venepuncture has been shown to be associated with a lower incidence of complications and a higher rate of success than 'blind' venepuncture, and is therefore strongly recommended for all venesection procedures 1.
- The benefits of venesection have been established, despite the absence of randomized controlled trials, and it is the accepted standard of care for conditions such as hemochromatosis, where reducing blood volume or removing excess iron is beneficial for managing the disease 1.
- Long-term unwanted effects of venesection have not been reported, and the majority of patients comply with treatment, making it a well-tolerated and effective procedure for therapeutic purposes 1.
From the Research
Venesection Procedure
The procedure for venesection, also known as phlebotomy, is a medical treatment that involves the removal of blood from the body 2.
- The procedure is generally safe and carries few side effects, but it should be performed by persons familiar with the procedure and management of the attendant complications 2.
- Before commencing therapeutic venesection, management goals in terms of laboratory parameters should be set for individual patients, and these patients should be monitored regularly to ensure that set targets are met and not overshot, which could render them anaemic and acutely symptomatic 2.
- The removal of blood is typically done to treat conditions such as hereditary haemochromatosis, polycythaemia, and porphyria cutanea tarda 2.
Potential Complications
As with any medical procedure, there are potential complications associated with venesection, including:
- Infection 3
- Phlebitis and thrombophlebitis 3
- Emboli 3
- Pain 3
- Haematoma or haemorrhage 3
- Extravasation 3
- Arterial cannulation 3
- Needlestick injuries 3
Setting Up a Venesection Service
When setting up a venesection service in a doctor's surgery, it is essential to consider the pathophysiology of the conditions being treated, the rationale and goals of therapeutic venesection, and the procedure itself 2.