A nurse is caring for a postoperative client who has a chest tube connected to suction and a water seal drainage system. Which of the following indicates to the nurse that the chest tube is functioning properly?

Choice A reason: Fluctuation, also known as tidaling, in the water seal chamber with respiration indicates that the system is patent and the pleural space is responsive to intrathoracic pressure changes. This is a normal finding and confirms that the chest tube is functioning properly by allowing air or fluid to escape while preventing backflow. Choice B reason: Absence of fluid in the drainage tubing may indicate that there is no drainage, which could be normal postoperatively, or it could suggest a blockage or malfunction. It is not a definitive sign of proper function and requires further assessment. Choice C reason: Continuous bubbling in the water seal chamber is abnormal and typically indicates an air leak in the system or from the lung. Intermittent bubbling may be expected with pneumothorax, but continuous bubbling warrants investigation. Choice D reason: Equal amounts of fluid in each collection chamber is not a relevant indicator of chest tube function. The chambers are designed to collect drainage over time, and the volume may vary depending on the clinical situation. The focus should be on the amount, color, and rate of drainage, not symmetry.