Final answer:
In case of no blood flow during venipuncture, slightly rotate or adjust the needle's position, switch the tubes or gently withdraw the needle slightly; if the issue persists, terminate the procedure and seek assistance.
Step-by-step explanation:
If you're performing a venipuncture and the needle appears to be inside the vein but no blood is flowing into the tube, you may try to slightly rotate the needle or adjust the needle's position slightly within the vein in case it's not properly aligned with the vein's lumen. If there's still no blood flow, gently withdraw the needle slightly in case it has passed through the vein.
Do not pull the needle completely out as this could cause multiple punctures and discomfort to the patient. Switching the tubes is also a viable option if the vacuum tube has lost its vacuum. If the problem persists, it's best to terminate the procedure and consult an experienced colleague. Troubleshooting steps should be taken with care to maintain patient safety and comfort.