What position should the stopcock be left in at all times?

• A. Off
• B. On
• C. Closed
• D. Tilted

Answer: (B)

The stopcock’s job is to control whether suction is actively connected to the chest drainage system. Leaving it in the On position ensures continuous suction is applied to the chest tube, which maintains a negative intrathoracic pressure and allows ongoing drainage of air or fluid. If suction is interrupted by turning the stopcock off or to a closed position, air can enter or re-accumulate in the pleural space and drainage can stop, increasing the risk of pneumothorax or ineffective drainage. Tilting isn’t a standard or reliable way to manage the system and can disrupt flow. So, to keep the system functioning and protect the patient, the stopcock should remain in the On position at all times.