MEDICARE INFORMATION FOR ANESTHESIOLOGISTS IS LOCATED AT THE ANESTHESIOLOGISTS CENTER 
https://www.cms.gov/center/anesth.asp

AMERICAN SOCIETY OF ANESTHESIOLOGISTS (ASA)  CODING RESOURCES:

RELATIVE VALUE GUIDE and  CROSSWALK (C)
http://www.asahq.org/shop-asa 

ASA (Standards, Guidelines & Statements)

http://www.asahq.org/quality-and-practice-management/standards-guidelines-and-related-resources-search