Which of the following symptoms is NOT associated with an open pneumothorax?

The presence of an open pneumothorax, commonly referred to as a "sucking chest wound," typically manifests with several specific symptoms. Among these symptoms, frothy or bubbly fluid around the injury is often observed, as air escapes through the chest wall during inhalation and exhalation. Difficulty breathing is also a primary concern due to the compromised lung function caused by the air entering the pleural space. Coughing up blood can occur, especially if there is lung injury or associated trauma.

While a rapid heart rate can occur in response to hypoxia or shock, it is not a symptom specifically indicative of an open pneumothorax itself. Instead, it is a more generalized response that can accompany various types of injuries and medical conditions. Therefore, recognizing that rapid heart rate is not directly attributed to the presence of an open pneumothorax helps clarify its exclusion from the list of associated symptoms.