So, we have started doing lumbar plexus blocks for our hip surgeries (along with GA so they are for post-op pain). Yesterday, it was the first lumbar plexus block for both myself and my MD so we decided to do it together (typically, I can just do it if I want or he hooks the patients up to the monitor while I do the blocks). Don't remember a whole lot about the patient except she was a little old lady with CAD, stents, etc...for a total hip replacement. We went in the OR and sat her up on the stretcher for the block (had to use the Hana table and we don't put people to sleep on that horrible thing). Gave 2mg Midaz in pre-op and then 2 mg in room. Patient complaining of pain on sitting up, complaining really loudly with skin localization and needle insertion, so I gave 2 mL Fentanyl about 2 minutes before we got good twitches and injected 30 mL 0.5% Bupivacaine with epi 1:200,000 (negative for aspiration of CSF/heme). So we quickly lay the patient down and find she has gone apneic and turned blue (within 30 seconds of injection...SpO2 down to 60s). We immediately started mask ventilation (easy mask), gave a small amount of Propofol (60 mg), Zemuron, and intubated. While we were doing this, we cycled the BP to find that she had a BP of 40/20!! An entire stick of Neo later, I got her up to 80/50. Started a neo gtt, IVFs, etc...She actually did pretty well during the case and only required about 2.5-3% ET Desflurane to keep her asleep and comfy (Bis in the 30s). What do you guys think happened? I'll tell you what we think after a few responses.