When performing arthroscopic surgery on the joint, it is necessary for the surgeon to put something inside the knee to distend or expand it. Over the years, different substances have been used — first nitrous oxide (laughing gas), then carbon dioxide. But studies showed that the use of any gas could result in a deadly embolism. Now surgeons use water or saline (salt solution).
Embolism is another word for an object (e.g., air, blood, fat) that travels through the bloodstream, lodges in a blood vessel, and blocks it. Even a small bubble of air introduced into the joint can travel to the heart or brain and cause sudden death. That air bubble is referred to as a venous air embolism.
Cases of sudden death from air embolism during joint arthroscopy are rare but serious enough to send some surgeons back to the lab to experiment and find out what’s causing this to happen. A new study is now available that might shed some light on what’s happening. It looks like the bags of saline-solution used to distend the joint might be the problem.
There can be small amounts of air trapped in the bags, which then get pumped into the joint. It is a standard practice to prime the tube between the bag and the arthroscopic pump but not necessarily to bleed the bag of any air before connecting it to the pump. This simple step in the preoperative procedure may eliminate the problem. More study of the problem is needed before we will know for sure but it sounds like the researchers are on the right track on this problem.