Final answer:
The most common cause of hematoma formation during a blood draw is the failure to remove the tourniquet before removing the needle. This keeps pressure in the vein, causing blood to leak into surrounding tissues once the needle is withdrawn. Other options, like excessive probing or not withdrawing the vacuum tube, are less commonly associated with hematoma formation during blood draws.
Step-by-step explanation:
The most common cause of hematoma formation during a blood draw is option b. Failure to remove the tourniquet before removing the needle. When the tourniquet is not removed, it can cause continued pressure in the vein, which may lead to seepage of blood into the surrounding tissues once the needle is removed, resulting in a hematoma. Proper procedure requires that the tourniquet be released before the needle is withdrawn to minimize this risk. In comparison, excessive probing with the needle to locate a vein (option a) may also cause a hematoma, but it is not as common when compared to the failure in tourniquet management. Options c and d do not typically have as direct an association with hematoma formation as the misuse of a tourniquet. A hematoma is generally an accumulation of clotted blood outside of blood vessels due to an injury to the wall of a blood vessel, allowing blood to seep out and pool in the surrounding tissues. Failure to manage the tourniquet correctly during phlebotomy can inadvertently create such an injury, leading to a hematoma.