Then let the pvt insurance company subpoena the charts in question. The hospital networks shouldn't devote an etnire office of disgruntled bedside nurses rifling through charts. this is so normalized that everyone on here thinks it is ok.
random chart/case reviews is essentially "standard of care" (so to say) at the hospital level when it comes to quality measures. This is like quality 101 stuff and is usually tied to something like recredentialing. If something bad happened in the future, they want a paper trail showing that there was continual assessments of your competence and that the hospital wasn't negligent in letting you practice without any periodic review.
We just randomly pull a certain number of charts for each doc and anesthetist each quarter and have various measures that we survey those charts for.