Fibrosis of the lungs can occur, resulting in dyspnea (shortness of breath), low blood oxygenation, and reduced functional residual capacity for as long as six years after the injury. As late as four years post-injury, decreased functional residual capacity has been found in most pulmonary contusion patients studied. During the six months after pulmonary contusion, up to 90% of people have difficulty breathing. In some cases, dyspnea persists for an indefinite period. Contusion can also permanently reduce the compliance of the lungs. Complications
Pulmonary contusion can result in respiratory failure—about half of such cases occur within a few hours of the initial trauma. Other severe complications, including infections and acute respiratory distress syndrome (ARDS) occur in up to half of cases. Elderly people and those who have heart, lung, or kidney disease prior to the injury are more likely to stay longer in hospital and have complications from the injury. Complications occur in 55% of people with heart or lung disease and 13% of those without. Of people with pulmonary contusion alone, 17% develop ARDS, while 78% of people with at least two additional injuries develop the condition. A larger contusion is associated with an increased risk. In one study, 82% of people with 20% or more of the lung volume affected developed ARDS, while only 22% of people with less than 20% did so.Pneumonia, another potential complication, develops in as many as 20% of people with pulmonary contusion. Contused lungs are less able to remove bacteria than uninjured lungs, predisposing them to infection.
These garments alternate layers of materials with high and low acoustic impedance (the product of a materials density and a waves velocity through it) in order to "decouple" the blast wave, preventing its propagation into the tissues. Treatment
No treatment is known to speed the healing of a pulmonary contusion; the main care is supportive. Attempts are made to discover injuries accompanying the contusion, to prevent additional injury, and to provide supportive care while waiting for the contusion to heal. Monitoring, including keeping track of fluid balance, respiratory function, and oxygen saturation using pulse oximetry is also required as the patients condition may progressively worsen. Monitoring for complications such as pneumonia and acute respiratory distress syndrome is of critical importance. Treatment aims to prevent respiratory failure and to ensure adequate blood oxygenation. Supplemental oxygen can be given and it may be warmed and humidified. When the contusion does not respond to other treatments, extracorporeal membranous oxygenation may be used, pumping blood from the body into a machine that oxygenates it and removes carbon dioxide prior to pumping it back in. Ventilation
Positive pressure ventilation, in which air is forced into the lungs, is needed when oxygenation is significantly impaired. Noninvasive positive pressure ventilation including continuous positive airway pressure (CPAP) and bi-level positive airway pressure (BiPAP), may be used to improve oxygenation and treat atelectasis: air is blown into the airways at a prescribed pressure via a face mask.