Noninvasive ventilation has advantages over invasive methods because it does not carry the risk of infection that intubation does, and it allows normal coughing, swallowing, and speech. However, the technique may cause complications;  it may force air into the stomach or cause aspiration of stomach contents, especially when level of consciousness is decreased.People with  signs of inadequate respiration or oxygenation may need to be intubated and mechanically ventilated. Mechanical ventilation aims to reduce pulmonary edema and increase oxygenation. Ventilation can reopen collapsed alveoli, but it is harmful for them to be repeatedly opened, and positive pressure ventilation can also damage the lung by overinflating it. Intubation is normally reserved for when respiratory problems occur, but most significant contusions do require intubation, and it may be done early in anticipation of this need. People with pulmonary contusion who are especially likely to need ventilation include those with prior severe lung disease or kidney problems; the elderly; those with a lowered level of consciousness; those with low blood oxygen or high carbon dioxide levels; and those who will undergo operations with anesthesia. Larger contusions have been correlated with a need for ventilation for longer periods of time.Pulmonary contusion or its complications such as acute respiratory distress syndrome may cause lungs to lose compliance (stiffen), so higher pressures may be needed to give normal amounts of air and oxygenate the blood adequately.
If it is severe enough, the hypoxemia resulting from fluid in the alveoli cannot be corrected just by giving supplemental oxygen; this problem is the cause of a large portion of the fatalities that result from trauma. Diagnosis
To diagnose pulmonary contusion, health professionals use clues from a physical examination, information about the event that caused the injury, and radiography. Laboratory findings may also be used; for example, arterial blood gasses may show insufficient oxygen and excessive carbon dioxide even in someone receiving supplemental oxygen. However, blood gas levels may show no abnormality early in the course of pulmonary contusion. X-ray
Chest X-ray is the most common method used for diagnosis, and may be used to confirm a diagnosis already made using clinical signs. Consolidated areas appear white on an X-ray film. Contusion is not typically restricted by the anatomical boundaries of the lobes or segments of the lung. The X-ray appearance of pulmonary contusion is similar to that of aspiration, and the presence of hemothorax or pneumothorax may obscure the contusion on a radiograph. Signs of contusion that progress after 48 hours post-injury are likely to be actually due to aspiration, pneumonia, or ARDS.Although chest radiography is an important part of the diagnosis, it is often not sensitive enough to detect the condition early after the injury. In a third of cases, pulmonary contusion is not visible on the first chest radiograph performed.