A critically ill patient has a central intravenous line inserted into the left subclavian vein. After the procedure, what nursing intervention is used to detect the most serious complication of this procedure?

Rationale:

A. Anxiety and fear usually increase respiratory rate and depth (hyperventilation). Hyperventilation blows off CO2, which can lead to respiratory alkalosis, not acidosis. Therefore, anxiety is not a predisposing factor for respiratory acidosis.

B. CNS depression from conditions such as stroke, brain injury, sedation, or neurologic disease can suppress the respiratory drive, leading to hypoventilation. Hypoventilation results in CO2 retention, which increases PaCO2 and lowers pH, producing respiratory acidosis.

C. DKA causes metabolic acidosis due to the accumulation of ketone bodies. The patient often develops Kussmaul respirations (deep, rapid breathing) to blow off CO2 as a compensatory mechanism, which is opposite of respiratory acidosis.

D. NG suctioning removes gastric acid, which can lead to loss of hydrogen ions, causing metabolic alkalosis, not respiratory acidosis. It does not directly affect CO2 elimination or the respiratory system.

E. Sedatives such as benzodiazepines, opioids, or barbiturates depress the CNS, including the respiratory centers in the medulla. This leads to hypoventilation, decreased alveolar ventilation, and CO2 retention, resulting in respiratory acidosis.

Rationale:
A. The system is functioning normally is incorrect because normal function of a water-seal chamber includes tidaling with respiration (the water level rises and falls with breathing) and intermittent bubbling, usually only during suction. Constant bubbling in the water-seal chamber indicates a problem, not normal function.

B. The patient has a pneumothorax is incorrect because while a pneumothorax may have caused the chest tube placement, the presence of constant bubbling in the water-seal chamber specifically indicates an air leak in the system, not necessarily a new or persistent pneumothorax.

C. The system has an air leak is correct. Constant bubbling in the water-seal chamber indicates that air is escaping somewhere in the system, either from the patient’s pleural space (ongoing pneumothorax) or from a loose connection, crack, or defect in the tubing or drainage system. The nurse should inspect all connections, tubing, and insertion site to locate and correct the leak.

D. The chest tube is obstructed is incorrect because obstruction typically prevents fluid or air from moving through the system, which may result in no tidaling or reduced drainage, not constant bubbling.