critical care medicine
How To Do Venous Blood Sampling
Tips and Tricks for Venous Blood Sampling
Butterfly needles attached to a syringe may be preferred for difficult venipuncture (eg, small veins in neonates, fragile veins in older adults). If a suitable vein is difficult to locate, try lowering the extremity and/or applying warm compresses ornitroglycerinointment to help dilate veins. Well-fitting gloves make palpation of the vein easier. Instruct patients to look away from the equipment and the procedure to help prevent a vasovagal episode. 