The therapist feels crepitus around the neck and anterior chest of a patient receiving mechanical ventilation with a high peak inspiratory pressure. Which of the following conditions does the patient likely have?

A. overdistention
B. ventilator-induced lung injury
C. perivascular edema
D. subcutaneous emphysema

?ANS: D
A. Incorrect response: Lung overdistention may cause barotrauma or volutrauma, but overdistention is not the same as subcutaneous emphysema.
B. Incorrect response: Subcutaneous emphysema can be considered a form of ventilator-induced lung injury. However, the term ventilator-induced lung injury (VILI) should not be considered synonymous with subcutaneous emphysema. VILI is a broader and more encompassing term, and involves barotraumas, volutrauma, atelectrauma, and biotrauma.
C. Incorrect response: Perivascular edema has no relationship with subcutaneous emphysema.
D. Correct response: Subcutaneous emphysema presents as pockets of air or gas under the skin of a patient receiving mechanical ventilation. The air pockets tend to arise in the neck and anterior chest, and produce a characteristic crackling sound and sensation called crepitus when palpated.
Subcutaneous emphysema occurs with or without pneumothorax. Although subcutaneous emphysema is usually not a life-threatening complication of mechanical ventilation, its presence should be interpreted by the therapist to mean that more serious and potentially life-threatening complications are possible.