All are true about lung contusion except

Lung contusion Incidence - 25% to 35% Clinical presentation--hypoxemia, hypercarbia, laboured breathing, X-Ray chest is used most commonly but the initial images are not so sensitive and may take 48 hrs to get the real pictures of contusion. Pulmonary contusions that are identifies early on chest film are frequently severe and often rapidly progress to respiratory failure Thoracic CT is valuable for the identification of pulmonary contusion and is the investigation of choice. To differentiate condition from atelectasis is a big task in CT l, one clue is atelectasis doesn't cross pulmonary fissures where as contusions are not limited by ventilatory segments Most of the cases are managed conservatively with pain relief, fluids and observation Fluid restriction is not advised as believed earlier Once very few cases require mechanical ventilation where there is falling of Oxygen satiration