Why pneumothorax patient xray taken in expiratory position?
Answers
An expiratory chest radiograph can be taken in either a PA or AP projection, and can also be taken with a mobile/portable unit. They are used to help detect small pneumothoraces (although sensitivity is not increased over inspiratory chest radiographs 1), and to assess for inhaled foreign bodies or gas trapping in COPD 2,3.
Chest radiographs may inadvertently be acquired in expiration (instead of inspiration), and this will affect interpretation with the cardiac silhouette appearing enlarged, and spurious basal opacities being the most common false positive findings 3.
Patient position
PA projection
patient is erect facing the upright image receptor, the superior aspect of the receptor is 5 cm above the shoulder joints
the chin is raised as to be out of the image field
shoulders are rotated anteriorly to allow the scapulae to move laterally off the lung fields, this can be achieved by either:
hands placed on the posterior aspect of the hips, elbows partially flexed rolling anterior or
hands are placed around the image receptor in a hugging motion with focus on lateral movement of the scapulae
shoulders are depressed to move the clavicles below the lung apices