When should a decompression needle be used?

A decompression needle should be used in cases of tension pneumothorax because this condition occurs when air enters the pleural space and cannot escape, leading to increased pressure in the thoracic cavity. This pressure can collapse the lung and compromise cardiac function, making immediate intervention critical.

Using a decompression needle, typically inserted into the second intercostal space at the midclavicular line, allows trapped air to escape, relieving the pressure and allowing the lung to re-expand. This procedure can be life-saving, as it addresses the immediate threat to the patient's respiratory and circulatory systems.

Regarding the other options, fractures do not necessitate the use of a decompression needle, respiratory distress requires a different assessment and management approach, and the presence of bleeding typically calls for hemorrhage control techniques rather than needle decompression.