The portable lateral film, like the decubitus films, are not often obtained in the ICUs but can better delineate the costophrenic sulci and the frequently obscured lower lobes to advantage. The lateral film is particularly useful when only one lower lobe is involved since the normal lung can provide a window to the opposite lung without the confusion of laterality. Both the decubitus and the lateral films can significantly increase the awareness of basal lung disease, unsuspected on the portable AP films.
Computed tomography generally is recognized as providing increased resolution compared with more conventional roentgenographic techniques. It is employed routinely to evaluate pulmonary nodules, mediastinal adenopathy, chronic lung disease, and to guide diagnostic procedures (eg, needle biopsy). Abdominal CT can be used effectively to diagnose postoperative abscesses in patients showing slow clinical improvement or deterioration in their overall condition. Also, lower thoracic CT, during or after abdominal CT, has been found to be very useful in the diagnosis of occult pneumothorax after blunt head or abdominal trauma. While the efficacy of the portable chest roentgenogram has been studied extensively, less attention has been given to the value of chest CT in the evaluation of critically ill patients. Selected patients with multisystem trauma who had chest CT were significantly benefitted 70 percent of the time by the discovery of additional diagnostic information affecting management and outcome in a recent series.
An important factor in the management of our three patients was the diagnosis of persistent intrathoracic disease which did not seem to respond to appropriate therapy In each case, a thoracic CT was performed in order to a define pathologic condition that was not evident on the conventional portable chest roentgenogram. Numerous portable chest x-ray films led us to underestimate the extent of the chest abnormalities in all three cases. Computed tomography revealed several unsuspected intrathoraeicabsce.sses, occult pneumothoraces, and a bronchopleural fistula. With correct diagnoses, inappropriate therapy was discontinued, and appropriate therapy was implemented.
Although moving a critically ill patient from the ICU to the CT scanner is a potentially dangerous process, the diagnostic advantage of a chest CT often justifies the risk. We recommend that chest CT be considered for patients with intrathoracic pathologic condition under the following conditions: (1) when the clinical course does not correlate with the current diagnostic examinations, particularly the portable chest roentgenogram, and (2) when the patient is sufficiently stable to tolerate transportation to the diagnostic facility.