Table 1

Definitions of operating room tiers

Variable	Operating room tier
Variable	1	2A	2B	3
Length of surgical procedure, h	< 1	< 1.5	< 1.5	< 5
Length of recovery from surgery, h	< 1	< 2	< 2	< 2
Operating room staffing (rotating charge nurse or other nurse covers lunch breaks)	1 RN (circulator)	2 nurses: 1 RPN (scrub) and 1 RN (circulator)	2 nurses: 1 RPN (scrub) and 1 RN (circulator)	2–2.5 nurses: 1 RPN (scrub), 1 RN (circulator) and 1 float
ASA	≤ 3	≤ 3	≤ 3	≤ 3
Anesthesia	No general anesthesia	General or regional anesthesia or both	General or regional anesthesia or both	General or regional anesthesia or both
Examples	Distal extremity procedures (hands, legs), foot procedures, ankle arthroscopy, carpal tunnel syndrome	Knee or hip arthroscopy, hernia, fusion, ACL repair	Intra-abdominal (e.g., gallbladder), arteriovenous fistula	Facelift, breast lift, abdominoplasty, liposuction

ACL = anterior cruciate ligament; ASA = American Society of Anesthesiologists score; RPN = registered practical nurse; RN = registered nurse.