What can cause a collapsed vein during blood collection?

A collapsed vein during blood collection is most commonly caused by a too strong vacuum on a small vein. When a vacuum tube is used that has a high negative pressure, it can exert significant force on a vein, especially if it is small or fragile. This pressure can lead to a situation where the vessel walls cannot withstand the suction, causing the vein to collapse.

In practice, choosing the right size of tube and understanding the characteristics of the vein being accessed are crucial for preventing this complication. A smaller vein, which may not have as much structural integrity, is particularly susceptible to collapsing under excessive vacuum pressure. Therefore, it’s essential for healthcare professionals to assess the patient's veins beforehand and make appropriate choices regarding both the needle and the collection tube to mitigate this risk.