What should be done if blood flow stops during a venipuncture?

During a venipuncture, if blood flow stops, adjusting the needle slightly or repositioning it can often help to restore blood flow. This occurs because the needle may have moved out of the vein or might not be properly aligned within the lumen of the vein. By making a slight adjustment, you can potentially re-enter the blood vessel and facilitate re-establishment of blood flow for the collection.

Care must be taken when repositioning the needle to avoid causing discomfort or additional trauma to the patient. Other methods like asking the patient to make a fist or applying more pressure on the tourniquet are less effective and may lead to unnecessary complications. Removing the needle entirely may result in having to perform the venipuncture again, which can add to the patient's discomfort. Therefore, appropriately adjusting the needle position is the most effective immediate response when blood flow ceases.