Introduction

The portable chest radiograph is the primary imaging modality on the critical care unit. Daily physical examination of sedated, intubated patients may be difficult and new or rapidly evolving changes in cardiorespiratory status may only be appreciated on chest radiography.

The routine chest radiograph

The efficacy and accuracy of the portable antero-posterior (AP) chest radiograph in assessing cardiopulmonary or pleural complications in critical care and its role in detecting malpositioned monitoring devices have been evaluated in many studies. Although undoubtedly the chest radiograph is valuable in the assessment of complications after intervention or change in clinical status, the role of the ‘routine’ daily radiograph is more controversial. Although not specifically recommending against routine radiography, one should emphasize the value of more targeted investigations.

Technical considerations

Technique

Optimal radiographic technique is essential to maximize the efficacy and accuracy of bedside radiography. The AP chest radiograph should be obtained with the patient upright using a film-to-focus distance (FFD) of 1.8 m and 5 degrees caudal angulation of the x-ray beam. In supine patients, the FFD should be 1.1 m with a perpendicular x-ray beam. Consistency in technique and positioning is critical for optimal evaluation on serial examinations. Whenever possible, care should be taken to remove extrinsic tubing and objects from the patient's chest before exposure.