Interesting to find out that the contents of epidurals are not standardized across facilities. If that is the case, then how can one definitely opine on the safety of them when the contents are locally designed cocktails?
It's not as if people are pushing random drugs into epidurals. There's a small number of drugs that are commonly used and the differences come down to selecting the classes of drugs to be used, the particular drugs from those classes, and the dosing. There's no one right answer. In other words, it's just like the rest of anesthesia.
> how can one definitely opine on the safety of them
Because the statistics still include all those variations. The variations are also not that huge, and are also independently studied.
You might as well ask how we can talk about the risk/safety of general anesthesia, given that different hospitals and even different anesthesiologists use different drugs.