Is it better to keep the arm straight or bent during intravenous infusion?

Generally speaking, it is better to keep the hand straight during intravenous (IV) infusion. IV infusion involves delivering medications needed for treatment directly into the body through a vein. Under normal circumstances, the hand should remain relaxed during the infusion process, and local warmth should be maintained. Keeping the hand constantly clenched may cause the muscles and skin on the back of the hand to tighten, which can affect the stability of the puncture site, increase the risk of the needle piercing through the blood vessel wall, lead to needle displacement ("rolling needle"), and result in subcutaneous hematoma formation. Therefore, it is recommended to keep the hand straight and avoid prolonged clenching to prevent complications at the puncture site or prolongation of the infusion time.

During IV infusion, a pressure difference must be established between the patient's body and the infusion bottle to allow the medication to flow into the venous system. As the medication flows downward from the bottle, the internal pressure gradually decreases. At this point, atmospheric pressure pushes air through the air inlet tube into the bottle, ensuring that the pressure inside the bottle remains slightly lower than atmospheric pressure. This mechanism allows the medication to flow steadily and uniformly into the bloodstream. Therefore, patients are advised to keep their hand extended, positioned flat, and approximately one meter below the infusion bottle—this is considered the optimal position. If any discomfort occurs during the infusion, patients should promptly inform their doctor to prevent adverse effects.