If the water seal height is not maintained, which component is most likely responsible for adjusting it?

• A. The control chamber water level
• B. The patient position
• C. The suction regulator
• D. The drainage bottle

Answer: (A)

The water seal height is set by the amount of sterile saline in the water-seal (control) chamber. That chamber creates a liquid barrier that allows air to escape from the pleural space but prevents outside air from re-entering. If the water-seal height isn’t maintained, the most likely fix is to adjust the water level in this chamber by adding sterile saline to reach the prescribed mark. The suction regulator determines how much suction is applied, but it does not set the water-seal height. Patient position and the drainage bottle affect drainage flow more than the height of the water seal. So, the component responsible for adjusting the water-seal height is the water level in the control chamber.