It is true that our healthcare system is one of the best in the world. However, we are humans and thus, mistakes will happen. Some mistakes are minor, some missing paperwork, a forgotten prescription perhaps? However, there are big errors that are easy to spot and can cause irreparable damage to the patient. Some of these errors are so plain to see, we can't believe a doctor or other medical professional would make them.
These type of errors are known as a special type of medical negligence called gross negligence. Essentially, these errors leave a person typically shocked or irreparably altered in a way that wasn't planned by their medical treatment. For example, gross negligence cases have been characterized by crazy mistakes by medical professionals, like amputating the wrong leg or leaving a surgical instrument inside of a patient and sewing them back up. While the latter is more believable, since doctors can sometimes use hundreds of instruments or tools during an operation, it still isn't acceptable.
The reality is that these mistakes happen to people, even patients in for the most routine of surgeries. It almost makes patients second-guess if they even need medical treatment at all. However, cases of gross negligence are fairly rare in the scope of things, but that doesn't make it anymore tolerable. Doctors accused of gross medical negligence or hospital negligence should absolutely be held accountable for their actions, especially when it causes further injury.
There isn't one type of specific case that guarantees gross negligence on behalf of a medical professional or hospital staff. Rather it is the nature of the error itself. If the error is plain to see, even by someone with no medical training, it's likely gross negligence. Figuring out if your injury is due to negligence or gross negligence can change how damages are pursued.
Source: injury.findlaw.com, "Gross negligence and lack of informed consent," Accessed January 9, 2017