Why keep the chest-tube drainage system closed?

• A. To prevent air entry and maintain sterility.
• B. To allow air exchange with the environment.
• C. To increase drainage rate.
• D. To reduce patient movement.

Answer: (A)

Keeping the chest-tube drainage system closed preserves a contained, sterile environment and maintains negative pressure in the pleural space. The chest tube system is designed to let air and fluid exit the chest while preventing air from flowing back in. If the system were open to the environment, air could rush into the pleural space, worsening a pneumothorax or hindering lung re-expansion, and bacteria could contaminate the chest cavity, increasing infection risk. A closed setup sustains controlled drainage and sterility, which are essential for effective healing. Opening the system would defeat the one-way flow and sterility, and it wouldn’t inherently make drainage faster; reducing movement isn’t the primary goal of keeping it closed.