Editing Decompression illness (section)

===Arterial gas embolism===
{{see also|Air embolism#Decompression illness}}
When a diver holds their breath during an ascent the reduction in pressure will cause the gas to expand and the lungs will also have to expand to continue to contain the gas. If the expansion exceeds the normal capacity of the lungs, they will continue to expand elastically until the tissues reach their tensile strength limit, after which any increase in pressure difference between the gas in the lungs and the ambient pressure will cause the weaker tissues to rupture, releasing gas from the lungs into any permeable space exposed by the damaged tissue. This could be the pleural space between the lung and the chest walls, between the pleural membranes, and this condition is known as pneumothorax. The gas could also enter the interstitial spaces within the lungs, the neck and larynx, and the mediastinal space around the heart, causing interstititial or mediastinal emphysema, or it could enter the blood vessels of the venous pulmonary circulation via damaged alveolar capillaries, and from there reach the left side of the heart, from which they will be discharged into the systemic circulation. On the way out through the aorta the gas may be entrained in blood flowing into the carotid or basilar arteries. If these bubbles cause blockage in blood vessels, this is [[arterial gas embolism]]. Vascular obstruction and inflammation caused by gas bubbles causes [[end organ damage]] to most tissues.<ref name="Cooper" /> Sufficient pressure difference and expansion to cause this injury can occur from depths as shallow as {{convert|1.2|m|ft}}.<ref name="DAN FAQ" />