What is the primary risk of not using a vented chest seal on a chest wound?

The primary risk of not using a vented chest seal on a chest wound relates to the potential worsening of a pneumothorax. When a chest wound is present, particularly a penetrating one, there is a risk that air can enter the pleural space, leading to a pneumothorax, where air accumulates in the pleural cavity and causes pressure to build up around the lungs.

Without a vented chest seal, air can enter the pleural space during inhalation but cannot escape during exhalation, which can result in a tension pneumothorax. This condition is life-threatening as it compromises the function of the lungs and can rapidly lead to respiratory failure and cardiovascular collapse due to the shift of mediastinal structures and impaired venous return to the heart. A vented chest seal allows trapped air to escape while preventing additional air from entering, effectively managing the pressure in the pleural cavity.

Thus, utilizing a vented chest seal is crucial to prevent the escalation of a pneumothorax and maintain adequate respiratory function.