Ketamine patient-controlled analgesia for dysesthetic central pain

Study Design: Case report. Objectives: To describe the first use of intravenous (IV) ketamine as the sole agent in a patient-controlled analgesic delivery system (ie PCA) in a patient with cervical syringomyelia. Setting: A tertiary-care university teaching hospital in New York City. Methods: A 41-year-old tetraplegic female on high-dose opioids suffering from intractable dysesthetic central pain received her best pain relief from a low-dose ketamine infusion after failing trials with multiple neuropathic medications. After several weeks of titrating her infusion rate up and down, she was switched to an IV ketamine PCA device. Results: The patient was maintained on an IV ketamine PCA for almost 1 year under the following settings: 2.7 mg/h basal rate; 2.7 mg/h demand dose; 15 min lockout period. Although she continues to report some pain, it has dramatically decreased since the ketamine PCA was instituted, enabling us to significantly reduce her opioid dosage. Conclusions: Ketamine PCA may be a viable treatment option in patients suffering from intractable central pain. The rationale for this treatment, along with dosing guidelines and possible drawbacks, is discussed.