Difficulty: Medium

Average Score: 50%

When using the evacuated tube method, which of the following will result in a failed venipuncture if the needle is at a 45 angle upon insertion?

Rationale

The needle will go completely through the vein.

In the evacuated tube method, inserting the needle at a 45-degree angle can lead to the needle penetrating entirely through the vein, especially if the needle is too long or the angle of insertion is not optimal. This scenario would prevent successful blood draw and is a common cause of failed venipuncture.

A (The needle will collapse the vein.) YOUR ANSWER

Collapsing the vein typically occurs when there is excessive vacuum in the tube or if the needle is inserted too quickly, but not specifically due to the angle of insertion. A 45-degree angle does not inherently cause vein collapse; rather, it may cause other complications depending on technique and patient anatomy.

B (The needle will go completely through the vein.) CORRECT

When the needle is inserted at a 45-degree angle, it can puncture through the opposite wall of the vein if the insertion depth is not carefully controlled. This results in a failed venipuncture as the blood cannot be properly drawn from the vessel, making this the correct answer.

C (The needle will miss the vein superficially.) YOUR ANSWER

Missing the vein superficially usually occurs with a too-shallow insertion or poor aim but is less likely at a 45-degree angle. If the angle is sufficient, the needle should be able to enter the vein, making this choice incorrect in the context of the angle specified.

D (The needle will contact the upper wall of the vein.) YOUR ANSWER

Contact with the upper wall of the vein can happen at various angles but does not necessarily result in a failed venipuncture. If the needle merely touches the upper wall, it can still successfully draw blood as long as it is within the lumen of the vessel.

Conclusion

Inserting the needle at a 45-degree angle during venipuncture can lead to complications, including the needle going completely through the vein, which constitutes a failed attempt. Understanding the implications of needle angle and technique is essential for successful venipuncture, as improper insertion can lead to various other issues that do not necessarily prevent blood collection.

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