Marked variability in peri-partum anesthetic management of patients on buprenorphine maintenance therapy (BMT): can there be an underlying acute opioid induced hyperalgesia precipitated by neuraxial opioids in BMT patients?

OBJECTIVES: To compare adequacy of peri-partum pain management with or without neuraxial opioids in patients on buprenorphine maintenance therapy (BMT).
METHODS: After institutional review board approval for the study protocol, retrospective peripartum anesthesia/analgesia data of BMT patients for five-year period were accessed and analyzed.
RESULTS: Out of reviewed 51 patient charts, nineteen patients were found eligible for final comparative analysis. The daily amounts of peri-partum rescue analgesics with vs without neuraxial opioids were equianalgesic doses of parenteral hydromorphone (10.7 +/- 13.8 mg vs 2.6 +/- 0.7 mg, P = 0.45 for vaginal delivery; 16.4 +/- 21.1 mg vs 5.3 +/- 3.6 mg, P = 0.42 for elective cesarean section (CS)), oral ibuprofen (1.1 +/- 0.5g vs 0.8 +/- 0.4g, P = 0.37 for vaginal delivery; 1.1 +/- 0.2g vs 1.6 +/- 0.6g, P = 0.29 for elective CS), and acetaminophen (0.2 +/- 0.4g vs 0 +/- 0g, P = 0.56 for vaginal delivery; 0.3 +/- 0.3g vs 0.2 +/- 0.2g, P = 0.81 for elective CS). In the patients who underwent emergent CS after failed labor (all had received epidural opioids), there was clinical trend for higher daily amounts ofperi-partum rescue analgesics (parenteral hydromorphone 35.6 +/- 37.5 mg; oral ibuprofen 1.2 +/- 0.4g; oral acetaminophen 1.2 +/- 0.5g), when compared with vaginal delivery patients or elective CS patients who all had received neuraxial opioids.
CONCLUSIONS: As the study was underpowered (n = 19), future adequately powered studies are required to conclude for-or-against the use ofneuraxial opioids in BMT patients; and pro-nociceptive activation by neuraxial opioids may be worth investigating to improve our understanding of peripartum pain management of BMT patients.