Difficulty: Hard

Average Score: 36%

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.

When inserting a needle at a 45° angle, there is a significant risk of the needle passing entirely through the vein, especially if the depth of insertion is not carefully controlled. This can lead to a failed venipuncture as the needle may exit the opposite side of the vein, making it challenging to collect blood.

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

If the needle is inserted correctly, the vein should not collapse. Vein collapse typically occurs when negative pressure is applied too forcefully or when the vein is fragile. A 45° angle alone does not cause vein collapse unless combined with improper technique or conditions.

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

Inserting the needle at a 45° angle increases the likelihood of it penetrating too deeply, potentially resulting in the needle passing through the vein. This outcome is the most common failure associated with improper angling during venipuncture, thus making it the correct answer.

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

Missing the vein superficially generally occurs when the needle is not inserted at an adequate angle or depth. At a 45° angle, there is an increased risk of entering the vein; therefore, this option does not accurately reflect the consequences of the angle specified.

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

While it is possible for the needle to contact the upper wall of the vein, this contact does not guarantee a failed venipuncture. If the needle only touches the upper wall, it may still be positioned well enough to access the vein and successfully draw blood.

Conclusion

Inserting a needle at a 45° angle during venipuncture can lead to significant complications, particularly the risk of the needle going completely through the vein, which results in a failed attempt to draw blood. Understanding the correct angle and depth of needle insertion is crucial for successful venipuncture and minimizing patient discomfort. Other incorrect options either do not directly result from this angle or describe situations that do not lead to a failed procedure.

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