Pulmonary overinflation occurs when the lungs are subjected to increased pressures, often due to improper exhalation during ascent after a dive. This situation can lead to the rupture of the alveolar lining, which is crucial for gas exchange in the lungs. When a diver ascends too quickly or fails to exhale adequately, expanding air within the lungs can cause the fragile walls of the alveoli to stretch beyond their limits, resulting in tearing. This rupture can lead to serious complications, such as air embolism, where air bubbles enter the bloodstream, significantly affecting circulation and potentially leading to life-threatening conditions.
The other possible answers do not align with the described effects of pulmonary overinflation. Increased oxygen saturation would typically not occur; instead, the rupture could decrease oxygen exchange. Similarly, pulmonary overinflation does not involve a reduction in lung volume, as it specifically entails an increase in volume or pressure that the lungs cannot accommodate. Lastly, while nitrogen absorption is a concern in diving, pulmonary overinflation is not related to the speed of nitrogen absorption but rather to the mechanical stress placed on lung tissue during over-inflation.