What syringe size is used for gentle steady manual suction during transfemoral venous cannulation?

• A. 5 mL
• B. 10 mL
• C. 20 mL
• D. 50 mL

Answer: (B)

Gentle steady suction hinges on using a syringe that provides the right amount of negative pressure to confirm venous entry without causing trauma. The syringe size determines how strong the suction is when you pull the plunger. A smaller syringe tends to generate stronger suction for the same amount of pull, which can cause the vein to collapse or damage the vessel; a larger syringe produces milder suction that may not give a reliable backflow signal quickly. The 10 mL syringe offers the best balance: enough backflow to clearly indicate venous access, but not so much suction that it risks injury. Smaller than this can be too aggressive, and larger can be too passive, delaying confirmation.