Depressing the manual vent should occur only under which condition?

• A. Suction is connected and operating
• B. The patient is unstable
• C. The water column is at maximum
• D. The tube is kinked

Answer: (A)

The vent is a control used to apply or release suction in the chest-tube drainage system. It should be used only when suction is actually connected and operating because depressing the vent creates negative pressure in the system to help draw air or fluid out of the pleural space. If suction isn’t connected or isn’t working, depressing the vent could defeat the intended seal, allow ambient air to be drawn into the system, and risk losing negative pressure or introducing air into the chest. In short, the vent is there to boost suction when the suction source is active, not to be used at other times.