Which of the following is used to stabilize a patient's arm during a venipuncture?

Choice A Reason:
Anchoring the vein does not eliminate the need for a tourniquet. The tourniquet is applied to engorge the veins, making them more prominent and easier to puncture. Anchoring is a technique used after the tourniquet has already accomplished this task.

Choice B Reason:
While anchoring the vein can provide a more stable area for needle insertion, which might indirectly reduce pain, its primary purpose is not pain reduction. Pain during needle insertion is more directly influenced by the needle gauge, angle of insertion, and the phlebotomist's technique.

Choice C Reason:
Improving vein identification is not the direct purpose of anchoring. Vein identification is typically done visually and by palpation before the application of the tourniquet and before anchoring the vein. Anchoring is performed to stabilize the vein once it has been identified.

Choice D Reason:
The primary purpose of anchoring the vein is to minimize its movement during venipuncture. This is important because it helps prevent the needle from slipping out of or through the vein, which can cause discomfort and bruising, and may require another puncture attempt.

Choice A Reason:
The recommended heel stick depth of 2.0 mm is based on the need to minimize the risk of injury to the infant. Penetrating deeper than this can increase the likelihood of hitting bone, which in infants can be as close as 2.0 mm under the skin of the plantar surface of the heel. This depth is sufficient to obtain a blood sample without risking injury to deeper tissues or bone.

Choice B Reason:
A depth of 2.5 mm may be too deep for some infants, especially preterm or very small infants, where the calcaneus (heel bone) is closer to the surface. While this depth might still be safe for some infants, it does not provide the same margin of safety as the 2.0 mm recommendation and could potentially lead to bone puncture or other injuries.

Choice C Reason:
A depth of 3.0 mm significantly increases the risk of bone puncture, especially in infants with less subcutaneous fat or in those who are preterm. This depth could easily breach the protective layer of skin and subcutaneous tissue, leading to a higher risk of osteomyelitis, an infection of the bone, which can be a serious complication in infants.

Choice D Reason:
A depth of 3.5 mm is considered too deep for a heel stick procedure and is likely to cause injury to the infant. This depth would almost certainly penetrate the bone in most infants, leading to severe pain, potential for infection, and other complications. It is well beyond the safe range recommended by CLSI and should be avoided.