While caring for a client with a three-chamber chest drainage system, the nurse notes that there is no fluctuation in the second chamber. An explanation for the nurse's observation is: A. The lung has re-collapsed. B. The amount of suction is excessive. C. The lung has re-expanded. D. The chamber needs emptying-

A three-chamber chest drainage system is a device used to drain air and fluid from the pleural space (the area between the lung and the chest wall), allowing the lung to re-expand. The system contains three chambers: 1. A collection chamber, where the drained fluid and air is held. 2. A water-seal chamber that prevents air from going back into the patient's lung and enables monitoring of fluid fluctuation. 3. A suction control chamber, which regulates the amount of suction applied to the lung.

Now, let's evaluate each choice to determine which one best explains the observation of no fluctuation in the second (water-seal) chamber: A. The lung has re-collapsed: If the lung has re-collapsed, there would be an increase in the air collected in the first chamber, and the second chamber would exhibit continuous bubbling due to the ongoing air leakage. B. The amount of suction is excessive: Excessive suction would cause the fluid level in the second chamber to fluctuate rapidly. The patient would also experience discomfort and pain. C. The lung has re-expanded: When the lung is re-expanded, the fluid and air in the pleural space have been drained. This means there is no more air entering the drainage system, and there will be no fluctuation in the second chamber. This is a normal finding indicating that the chest drainage system has been successful. D. The chamber needs emptying: If the collection chamber needs emptying, it would not affect the fluctuation of the second chamber. The issue would present in the first chamber, which holds the collected fluid.

Based on the analysis of each choice, the correct explanation for no fluctuation in the second chamber of a three-chamber chest drainage system is: C. The lung has re-expanded.