A phlebotomy technician is performing a venipuncture on a patient. When the technician inserts the needle, the vein collapses. Which of the following is a possible cause?
A Applying the tourniquet too tightly
B Inserting a smaller evacuated tube
C Applying the blood pressure cuff to 30 mm Hg
D Using a 25-gauge needle and syringe
The correct answer and explanation is:
The correct answer is A: Applying the tourniquet too tightly.
When performing venipuncture, the tourniquet is applied to help fill the veins with blood, making them more visible and easier to puncture. However, if the tourniquet is applied too tightly, it can cause excessive pressure in the veins, which can lead to the collapse of the vein during the insertion of the needle.
Applying the tourniquet too tightly reduces the venous return, causing the veins to appear engorged or “pop out.” However, if the pressure is too much, it causes the vein walls to become stiff, which makes them more likely to collapse when a needle is inserted. This is especially true for smaller veins or veins that are already fragile. The excessive pressure also makes it harder to draw blood effectively once the needle is in place, as the blood flow may not be sufficient due to the collapsed vein.
To avoid this, the tourniquet should be applied just tightly enough to make the veins more prominent but not so tight that it causes harm or collapse. It should not be left on for more than one minute to prevent damage to the veins or the blood from becoming stagnant.
Now, let’s briefly go through the other options:
- B: Inserting a smaller evacuated tube: A smaller evacuated tube would typically not cause a vein to collapse. In fact, smaller tubes often exert less suction, which can sometimes be beneficial in delicate veins.
- C: Applying the blood pressure cuff to 30 mm Hg: This is not typically a cause of vein collapse. A blood pressure cuff at this pressure would help the veins fill with blood, similar to a tourniquet but usually in a controlled manner, and wouldn’t collapse the veins.
- D: Using a 25-gauge needle and syringe: A 25-gauge needle is smaller than most, but it doesn’t typically cause vein collapse. However, a smaller needle may make it more challenging to draw blood if the vein is already difficult to access.
In conclusion, applying the tourniquet too tightly is the most likely cause of vein collapse during venipuncture.