The use of ketamine infusion to dramatically reduce opioid requirements in a patient whose high-dose intrathecal opioid pump was inadvertently cut during surgery

BACKGROUNDChronic opioid therapy may lead to high level tolerance development, hyperalgesia, and central sensitization, which further complicates long-term therapeutic management of chronic pain patients. In this case, we encounter a patient who was receiving over 15,000 morphine milligram equivalents through their intrathecal pain pump. Unfortunately, the intrathecal pump was inadvertently cut during a spinal surgery. It was deemed unsafe to delivery IV equivalent opioid therapy in this case; instead, the patient was admitted to the ICU and given a four-day ketamine infusion.METHODThe patient was started on a ketamine infusion at a rate of 0.5mg/kg/h, which was continued for three days. On the fourth day, the infusion rate was tapered over 12 h before being completely stopped. No coinciding opioid therapy was given during this time, which was only restarted in the outpatient setting.RESULTSDespite chronic high levels of opioid therapy immediately prior to the ketamine infusion, the patient did not experience florid withdrawals during the infusion period. Additionally, the patient experienced remarkable improvement in their subjective pain rating, which decreased from 9 to 3-4 on an 11-point Number Rating Scale, while simultaneously being managed on an MME