Analgesia for the parturient with chronic nonmalignant pain

Abstract

The prevalence of chronic pain, including but not limited to back, leg, and pelvic pain, is substantial during the peripartum period. Such pain may affect maternal and fetal outcomes. Therefore, obstetric anesthesiologists should be familiar with the analgesia provided to patients with chronic pain as well as any history of opioid dependence or substance abuse. We systematically searched PubMed and the Cochrane databases for all reports published on perioperative management of parturients with chronic pain. Abrupt cessation of opioid maintenance treatment or the use of partial opioid agonists-antagonists (commonly prescribed to parturients) is likely to cause acute withdrawal and uncontrolled pain that could lead to preterm labor, fetal abnormalities, or even fetal demise. Parturients receiving opioid maintenance therapy typically require higher doses of opioids for pain relief because they have a lower pain threshold. However, complying with such requests for higher doses may further compromise patient, fetus, and neonate safety. Opioid agonist-antagonist drugs, except buprenorphine, should be avoided in patients receiving maintenance opioid therapy. Drugs such as nalbuphine, butorphanol, pentazocine, and tramadol may incite severe withdrawal. Similarly, buprenorphine should not be offered for acute pain management to a parturient who is receiving methadone maintenance. Individualized plans of prenatal and neonatal care as well as breastfeeding are important during hospital admission of those dependent on opioids. Parturients who have implanted pain management devices such as spinal cord stimulators (SCSs) or intrathecal pumps (ITPs) should receive particular attention from anesthesiologists. Localizing the SCS lead or the ITP catheter positions is essential for safe administration of axial analgesia. Fluoroscopic images of the SCS leads and ITP catheters obtained during implantation are routinely available and should be acquired to avoid damage to these leads. Ultrasonography may be used for mapping the lead or catheter if fluoroscopic images cannot be obtained. The substantial prevalence of chronic pain in the obstetric population suggests the need for further research. Investigations should focus on gaining a better understanding of chronic pain during pregnancy, labor, and delivery so as to develop effective anesthetic and analgesic strategies.