The immediate step for managing an open pneumothorax requires placing what over the wound?

In the case of an open pneumothorax, the priority is to prevent air from continuously entering the pleural space through the wound. Applying an occlusive dressing over the wound is the immediate and critical step in management. This dressing should be airtight and function as a one-way valve, allowing air to escape from the pleural cavity during expiration but preventing air from entering during inspiration. This action helps to stabilize the thoracic cavity and mitigate the risk of further respiratory distress.

By contrast, options such as endotracheal intubation are more appropriate for addressing airway management rather than directly managing the open wound itself. An operation to close the wound may be necessary eventually, but it is not the immediate step, as such surgical interventions take time and cannot be done on the battlefield or during the early stabilization phase of a trauma response. A chest tube through the chest wound is typically reserved for managing a tension pneumothorax or complicated pneumothorax, rather than for the immediate management of an open pneumothorax, which directly requires the sealing of the perforated chest wall. Thus, using an occlusive dressing is essential for immediate stabilization and preventing further air entry.