TeslaCoil -
You do NOT need to go through a re-entry program. You DO need a bit of luck, be flexible, build relationships, and move slowly to get your skills back and not put patients at risk, in addition to be willing to take a financial hit (initially) to build your future.
I am doubled boarded in both pain and anesthesia. I did pain exclusively for ~15 years before transitioning back into anesthesia ~ 4 years ago. I had done ok in pain and have no particular ax to grind. But for the usual reasons cited in other threads, it was time to get out. I spoke with several anesthesia re-entry programs. They were either too far from home or charged thousands of $ (with no guarantee of employment) that it made no sense.
At the time, I was new to the area and did not have many professional contacts. I cold-called anesthesia practices, walked up to the surgical desk at some hospitals to meet with the anesthesia board runner. Eventually one group agreed to have lunch, and we hit it off. They let me do proctored cases (not paid) to establish a critical mass of general OR cases to apply for privileges. I was credentialed in around 3 months (and practiced pain part-time to keep some $ coming in). From there I worked PRN for the group anywhere from 8 - 24 hrs per week, and still did the part-time pain gig as the clinic volume dictated. I made it a point to introduce myself to the anesthesiologists, AAs, CRNAs .... all of them were incredibly professional and generous in helping me get up to speed. I was initially assigned bread and butter cases, and if I ran into trouble, there was always a partner to help out. My full capacity / reaction time of general OR skills returned over a couple of months, I took a NYSORA course to update my regional U-S skills, and I began doing L&D epidurals and C-sections. After a year I left pain altogether and hired on as an associate with the anesthesia group full-time. While there are the usual headaches as with ANY pain or anesthesia job, I am the happier now than I ever have been in my entire career.
I have had conversations with several former pain colleagues who want to go back into anesthesia - some part-time, some full. They too have been discouraged by the lack of great options afforded by re-entry programs. Others have gone back into anesthesia via the locums route or working part-time in an ASC (having not done a general anesthesia case in years). They have had a difficult time as their skills and speed have atrophied. If you can find an anesthesia group that can provide proctoring / mentoring for the first couple of months, and from there you can figure out if you want a split pain vs anesthesia schedule (or go full-anesthesia) that would be the ideal scenario. Given the shortage of anesthesiologists in the US, you'd be surprised at what opportunities exist if you put yourself out there.