Trauma Nurse Core Course (TNCC) Practice Exam

What is an expected finding in a patient with a thoracostomy connected to a chest drainage system?

1. Output of 200 mL/hr

2. Tubing clamp closed for transport

3. Dependent loops in the tubing to promote drainage

4. Fluctuations in the water seal chamber

The correct answer is: Fluctuations in the water seal chamber

In patients with a thoracostomy connected to a chest drainage system, fluctuations in the water seal chamber are expected when there is an air leak or free air in the pleural space. This fluctuation, known as tidaling, corresponds to the respiratory cycle; during inhalation, the water level drops, and during exhalation, it rises. Observing these fluctuations serves as a clinical indicator that the drainage system and the pleural space are functioning correctly, and it helps assess the status of the patient’s lung re-expansion and overall respiratory function. Other choices have considerations that do not align with best practice or expected norms in patient care. For instance, output of 200 mL/hr might be seen as significant depending on the clinical context but doesn’t directly indicate the expected functioning of the drainage system. Similarly, keeping the tubing clamp closed during transport can lead to complications such as tension pneumothorax, contrary to safe practice. Lastly, dependent loops in the tubing can create areas where fluid may accumulate, leading to potentially detrimental effects on drainage efficiency. In contrast, the monitoring of fluctuations in the water seal chamber is a reliable indicator of the drainage system's effectiveness.