When obtaining a drainage sample directly from the patient tube using the dependent-loop technique, what needle size is described as appropriate?

When obtaining a drainage sample directly from the patient tube using the dependent-loop technique, what needle size is described as appropriate?

• A. A temporary dependent loop and inserting a 20 gauge (or smaller) needle at a shallow angle
• B. An 18 gauge needle directly puncturing the tube
• C. A 14 gauge needle
• D. A 25 gauge needle

Answer: (A)

The technique aims to obtain a sterile sample from the chest-drainage tube without compromising the closed system. You form a short dependent loop in the drainage tubing so gravity helps the sample flow into the collection syringe, then insert a small-gauge needle—20 gauge or smaller—at a shallow angle to puncture the tubing just enough to draw the sample. A smaller needle minimizes the size of the puncture and reduces the risk of air entry or leaks through the tube, preserving system integrity. Larger gauges (like 18 or 14) would create a bigger puncture and raise the chance of damage or loss of suction, while a very small 25-gauge needle can be impractical and may not yield an adequate sample.

The technique aims to obtain a sterile sample from the chest-drainage tube without compromising the closed system. You form a short dependent loop in the drainage tubing so gravity helps the sample flow into the collection syringe, then insert a small-gauge needle—20 gauge or smaller—at a shallow angle to puncture the tubing just enough to draw the sample. A smaller needle minimizes the size of the puncture and reduces the risk of air entry or leaks through the tube, preserving system integrity. Larger gauges (like 18 or 14) would create a bigger puncture and raise the chance of damage or loss of suction, while a very small 25-gauge needle can be impractical and may not yield an adequate sample.