From the Guidelines
The parietal and visceral pleura are two continuous layers of serous membrane that play a crucial role in respiratory mechanics, with the parietal pleura lining the inner surface of the thoracic cavity and the visceral pleura closely adhering to the outer surface of the lungs. The relationship between the parietal and visceral pleura is essential for normal breathing, with the two layers being in close apposition due to the subatmospheric intrapleural pressure and surface tension created by the pleural fluid. The two mechanisms that contribute to 'pleural linkage' are:
- Surface tension, which occurs due to the cohesive forces between water molecules in the pleural fluid, causing the pleural surfaces to adhere to each other 1
- Subatmospheric intrapleural pressure, which creates a vacuum-like effect that keeps the visceral and parietal pleura in close apposition 1 Pleural linkage contributes to inhalation by ensuring that as the thoracic cavity expands, the lungs expand correspondingly, due to the negative intrapleural pressure increasing during inspiration and the visceral pleura following the parietal pleura outward. If there were a perforation in the thoracic wall and parietal pleura, as might occur in a penetrating chest injury, air would enter the pleural space from the outside, equalizing the intrapleural pressure with atmospheric pressure, disrupting the pleural linkage and causing partial or complete lung collapse on the affected side. This is consistent with the findings of the 2024 American Heart Association and American Red Cross guidelines for first aid, which highlight the importance of managing open chest wounds to prevent air entry into the pleural space and the potential for tension pneumothorax 1. In the context of a penetrating chest injury, it is crucial to prioritize the management of the open chest wound to prevent complications such as tension pneumothorax and to ensure proper lung ventilation. The use of a nonocclusive specialized dressing, such as a vented chest seal, may be beneficial in reducing air entry through the wound, but it is essential to be aware of the potential complications and monitor for signs of tension pneumothorax 1.
From the Research
Relationships of the Parietal and Visceral Pleura
- The parietal pleura lines the inner surface of the thoracic cavity, while the visceral pleura adheres to the lungs [@\4@].
- The two layers of pleura are in close proximity, with a thin layer of fluid between them, allowing for smooth movement of the lungs during breathing.
- The parietal and visceral pleura are connected by the pleural ligaments, which help to maintain their relationship.
Pleural Linkage
- Pleural linkage refers to the mechanical connection between the lungs and the thoracic cavity, which allows for coordinated movement during breathing [@\2@].
- The two mechanisms that contribute to pleural linkage are:
- The surface tension of the fluid between the parietal and visceral pleura, which helps to maintain their proximity.
- The elastic properties of the lungs and the thoracic cavity, which allow for expansion and contraction during breathing.
- Pleural linkage contributes to inhalation by allowing the lungs to expand and fill with air as the thoracic cavity increases in volume.
Disruption of Pleural Linkage
- A perforation in the thoracic wall and parietal pleura would disrupt pleural linkage by allowing air to enter the pleural space and creating a pneumothorax [@\1@, @\3@].
- This would cause the lung to collapse and prevent it from expanding during inhalation, leading to respiratory distress and shortness of breath.
- The disruption of pleural linkage would require medical intervention, such as needle decompression or tube thoracostomy, to restore the normal relationship between the lungs and the thoracic cavity [@\2@].