Venous air embolism related to the use of central catheters revisited: with emphasis on dialysis catheters

Abstract

Venous air embolism is a dreaded condition particularly relevant to the field of nephrology. In the face of a favourable, air-to-blood pressure gradient and an abnormal communication between the atmosphere and the veins, air entrance into the circulation is common and can bring about venous air embolism. These air emboli can migrate to different areas through three major routes: pulmonary circulation, paradoxical embolism and retrograde ascension to the cerebral venous system. The frequent undesirable outcome of this disease entity, despite timely and aggressive treatment, signifies the importance of understanding the underlying pathophysiological mechanism and of the implementation of various preventive measures. The not-that-uncommon occurrence of venous air embolism, often precipitated by improper patient positioning during cervical catheter procedures, suggests that awareness of this procedure-related complication among health care workers is not universal. This review aims to update the pathophysiology of venous air embolism and to emphasize the importance of observing the necessary precautionary measures during central catheter use in hopes of eliminating this unfortunate but easily avoidable mishap in nephrology practice.

Keywords: air embolism; catheter; central vein; haemodialysis; retrograde pathway.

Fig. 1.

Pathways of venous air emboli migration and their clinical sequelae. There are overlaps in the manifestations of emboli travelling along these pathways.

Fig. 2.

Computed tomography of a patient suffering from cerebral venous air emboli. Air emboli in the bridging veins of the right cerebral hemisphere (white arrows) and the dural sinus (black arrow). Reprinted with permission from Elsevier [56].