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Ketamine Decreases Postoperative Pain Scores in Patients Taking Opioids for Chronic Pain: Results of a Prospective, Randomized, Double-Blind Study

Authors

  • Antje M. Barreveld MD,

    Corresponding author
    • Department of Anesthesiology, Brigham and Women's Hospital, Boston, Massachusetts, USA
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    • Antje M. Barreveld, MD

      Role: This author helped conduct the study, analyze the data, and write the manuscript.

      Conflicts: Antje M. Barreveld reported no conflicts of interest.

      Attestation: Antje M. Barreveld has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.

  • Darin J. Correll MD,

    1. Department of Anesthesiology, Brigham and Women's Hospital, Boston, Massachusetts, USA
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    • Darin J. Correll, MD

      Role: This author helped design the study, conduct the study, analyze the data, and write the manuscript.

      Conflicts: Darin J. Correll reported no conflicts of interest.

      Attestation: Darin J. Correll has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.

  • Xiaoxia Liu MS,

    1. Department of Anesthesiology, Brigham and Women's Hospital, Boston, Massachusetts, USA
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    • Xiaoxia Liu, MS

      Role: This author helped analyze the data.

      Conflicts: Xiaoxia Liu reported no conflicts of interest.

      Attestation: Xiaoxia Liu has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.

  • Bryan Max MD,

    1. Department of Anesthesiology, Brigham and Women's Hospital, Boston, Massachusetts, USA
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    • Bryan Max, MD

      Role: This author helped design the study, conduct the study, and analyze the data.

      Conflicts: Bryan Max reported no conflicts of interest.

      Attestation: Bryan Max has seen the original study data and approved the final manuscript.

  • James A. McGowan MD,

    1. Department of Anesthesiology, Brigham and Women's Hospital, Boston, Massachusetts, USA
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    • James A. McGowan, MD

      Role: This author helped conduct the study and analyze the data.

      Conflicts: James A. McGowan reported no conflicts of interest.

      Attestation: James A. McGowan has seen the original study data and approved the final manuscript.

  • Louisa Shovel MBBS,

    1. Department of Anesthesiology, Brigham and Women's Hospital, Boston, Massachusetts, USA
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    • Louisa Shovel, MBBS

      Current affiliation: Department of Anaesthesia, Lister Hospital.

      Role: This author helped conduct the study and analyze the data.

      Conflicts: Louisa Shovel reported no conflicts of interest.

      Attestation: Louisa Shovel has seen the original study data and approved the final manuscript.

  • Ajay D. Wasan MD, MSc,

    1. Department of Anesthesiology, Brigham and Women's Hospital, Boston, Massachusetts, USA
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    • Ajay D. Wasan, MD, MSc

      Role: This author helped design the study, conduct the study, analyze the data, and write the manuscript.

      Conflicts: Ajay D. Wasan reported no conflicts of interest.

      Attestation: Ajay D. Wasan has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.

  • Srdjan S. Nedeljkovic MD

    1. Department of Anesthesiology, Brigham and Women's Hospital, Boston, Massachusetts, USA
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    • Srdjan S. Nedeljkovic, MD

      Role: This author helped design the study, conduct the study, analyze the data, and write the manuscript.

      Conflicts: Srdjan S. Nedeljkovic reported no conflicts of interest.

      Attestation: Srdjan S. Nedeljkovic has seen the original study data, reviewed the analysis of the data, approved the final manuscript, and is the author responsible for archiving the study files.

      Conflict of Interest/Disclosure summary: None of the authors have any conflicts of interest.


Reprint requests to: Antje M. Barreveld, MD, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA. Tel: (617) 732-8210; Fax: (617) 582-6131; E-mail: antje.barreveld@gmail.com.

Abstract

Background

Patients prescribed opioids for chronic pain may suffer from inadequate postoperative pain control. Ketamine is an adjuvant demonstrating analgesic and opioid-sparing effects. We hypothesize that an intravenous ketamine infusion in addition to opioid-based patient-controlled analgesia (PCA) improves postoperative pain relief in this patient population.

Methods

We evaluated 64 patients with chronic pain taking opioids undergoing nononcologic surgery. Patients were randomized to receive either postoperative hydromorphone PCA and continuous ketamine (0.2 mg/kg/hour), or hydromorphone PCA and saline. Patients provided numeric rating scale (NRS) pain scores for “worst,” “average,” and “least” pain following surgery. The primary outcome measure was change in patients' postoperative NRS scores compared with baseline NRS. Secondary and tertiary outcomes included postoperative day one 24-hour opioid use and the amount of opioid used 24 hours prior to hospital discharge.

Results

Fifty-nine patients were included in the analysis. Baseline patient characteristics were similar with the exception of age. Patients using ketamine had decreased “average” pain scores (percent change between postoperative and preoperative NRS) after surgery (13.5% decrease in the ketamine group vs 15.5% increase in NRS in the placebo group, P = 0.0057). There were no differences in “worst” or “least” pain scores or postoperative opioid use. Side effects between groups were similar.

Conclusions

Our study demonstrates that a postoperative ketamine infusion at 0.2 mg/kg/hour in addition to opioids results in a statistically significant reduction of “average” pain scores in patients undergoing surgery who take opioids for chronic pain. However, “least” and “worst” pain scores and the amount of opioid used postoperatively did not differ between groups. Thus, the use of a postoperative ketamine infusion at 0.2 mg/kg/hour provides limited benefit in improving pain management for this challenging population.

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