A medical assistant has just completed a venipuncture from the right median cubital vein on an adult patient who reports taking warfarin daily with a most recent INR of 3.2. After removing the needle and activating the safety device, what is the BEST post-collection action to prevent a haematoma?
- AApply firm direct pressure to the puncture site for at least five minutes with the patient's arm extended, then inspect the site before applying a gauze pad and tape. Correct
- BHave the patient bend the elbow tightly to compress the site for two minutes, then apply a pressure dressing and release the arm to normal position.
- CApply a tight elastic wrap circumferentially around the antecubital fossa to maintain hands-free pressure for ten minutes while preparing the labels.
- DApply light direct pressure for thirty seconds, then place an adhesive bandage and instruct the patient to keep the bandage on for two hours regardless of bleeding.
Why A is correct: Correct. Anticoagulated patients (INR 3.2 on warfarin) require prolonged pressure, typically five minutes or longer with the arm extended, to allow haemostasis before bandaging; pre-inspection confirms bleeding has stopped and a haematoma is not forming under the gauze.
Why B is wrong: Tempting because flexing the elbow feels like compression, but bending the elbow over a gauze pad actually opens the puncture and is a recognised cause of haematoma in anticoagulated patients; pressure must be direct and the arm kept straight.
Why C is wrong: Plausible because hands-free pressure sounds efficient, but a circumferential elastic wrap impairs distal venous return and can mask continued bleeding beneath the wrap, allowing a significant haematoma to develop unnoticed in an anticoagulated patient.
Why D is wrong: Tempting because thirty seconds is sometimes adequate for a non-anticoagulated patient with good clotting, but warfarin therapy at an INR of 3.2 markedly prolongs haemostasis, and inadequate pressure under an adhesive bandage is a primary cause of post-venipuncture haematomas.