Rebound Pain In Opioid-Tolerant Patients Following Peripheral Nerve Blockade For Ambulatory Surgery: A Retrospective Cohort Study

Dan Werry1, Garrett Barry1, Jon Bailey1, Regan Brownbridge1 Vishal Uppal1     

             1Department of Anesthesia, Pain Management and Perioperative Medicine, Dalhousie, Nova Scotia, Canada  

Group 1: 47 opioid tolerant patients

>60mg morphine/d or on methadone, buprenorphine or fentanyl patch     

Group 2: 3553 non-tolerant patients

Undergoing ambulatory surgery with single shot peripheral nerve block (with or without GA)

Phone questionnaire follow up  at 24 hours for pain scores (numerical rating scale, NRS) and satisfaction scores (Likert 1-5)

Review of hospital medical record data base for pain in PACU and return to hospital after discharge rates

14% opioid tolerant vs 29% non-tolerant patients had rebound pain

OR 0.44  (95% CI 0.18-1.10)

Rebound pain defined as transition of well controlled pain (NRS < 3 to > 7) within 24hr of block performance1

RPS defined as maximum home pain – PACU pain.

Opioid tolerant patients had reduced RPS owing to similar home pain but elevated PACU pain

Median difference of 2,

p= 0.004

12% opioid tolerant vs 3% non-tolerant patients returned to the hospital after discharge

OR 4.68 (95% CI 1.73 – 13.40)

Nearly identical reported satisfaction scores (Likert 1-5) between groups despite differences in RPS and return to hospital rates