An air embolism is best described as what?

An air embolism refers specifically to a situation where air bubbles enter the bloodstream and then become lodged in a blood vessel, often an artery. This can lead to blockages in blood flow, which may cause significant complications depending on where the blockage occurs. If an air bubble obstructs blood flow to critical areas such as the heart or brain, it can result in serious medical emergencies, such as a stroke or heart attack.

The other options describe different conditions that are not air embolisms. Air trapped around the heart refers more to a pericardial effusion, air trapped under the skin is known as subcutaneous emphysema, and the collapse of lung tissue is referred to as a pneumothorax. Each of these conditions has distinct causes and implications, differentiating them from the phenomenon of an air embolism. Understanding these conditions is important for scuba divers, as it highlights the importance of safe diving practices to prevent such incidents.