What is a blood patch used for in medical practice?

A blood patch is specifically utilized in medical practice to treat a condition known as a spinal headache, which can occur after procedures like a lumbar puncture. In this context, a blood patch involves the injection of a patient's own blood into the epidural space of the spine. The rationale behind this procedure is that the injected blood forms a clot, which can seal the leak of cerebrospinal fluid that is causing the headache. This method is effective because it uses the body's own materials to promote healing in the affected area, thereby alleviating pain and restoring normal pressure in the spinal canal.

The other options relate to different medical interventions that serve distinct purposes. For instance, tumor removal involves surgical techniques that do not connect to the concept of a blood patch. Draining joint fluid is performed to relieve pressure in joints or to analyze fluid for diagnostic purposes, and measuring cardiac function is related to assessing heart performance through various methods, none of which involve the epidural space or the use of a blood patch.