Portable Chest Roentgenography and Computed Tomography in Critically Ill Patients

4 Mar

Portable Chest Roentgenography and Computed Tomography in Critically Ill PatientsThe portable chest roentgenogram is one of the most frequent and effective diagnostic examinations used in the intensive care unit. It is easily obtained and frequently demonstrates most pathologic conditions, but does have shortcomings. Because a significant portion of the lower lobes lie below the diaphragmatic domes, pathologic findings in these areas may be obscured or unidentifiable on the portable chest roentgenogram. Under these circumstances, more sophisticated imaging techniques, including computed tomography (CT), may be required to clearly define the extent of the disease process. This report presents three instances in which the portable chest roentgenogram, while far from normal, fails to demonstrate the full extent of chest pathologic conditions accounting for a significant proportion of the patients overall clinical condition.

Materials and Methods
The portable roentgenographic images were made at a distance of 60 inches utilizing techniques which ensured reproducibility of the roentgenograms, insofar as the patients’ conditions would permit. When possible, the AP films were obtained with the patient leaning about 10 degrees forward of the true upright position to better reveal the lung bases. Those patients on ventilators had the exposures obtained during maximal inspiration. Exposure techniques were usually at 80 Kv and 6 mAs with exposure times maintained as short as possible to decrease motion artifacts. Neither portable lateral nor portable decubitus films were obtained in these patients, although these techniques have been described as effective for delineating pneumothorax, pleural effusions, and to more clearly demonstrate the lung bases on the “up” side. These techniques have the advantage of not requiring these severely ill patients to be moved from the ICU to the CT suite. However, they also have the disadvantage of difficulty in producing adequate quality films with reproducibility and difficulties in positioning patients. read
When the patients were moved to the CT suite for chest examination, these were performed on commercial scanners. The roentgenographic technique factors were 120 KVE 100 mAs, and 2 s scans. Mechanical ventilatory assistance or manual ventilation of the intubated patients were provided during the CT exams.