Efficacy Study of Ketamine for Postoperative Pain in Opioid Dependent Patients

Study Overview
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Brief Summary
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Patients who are dependent on opioids often have poor pain relief after major surgery. This study tests the hypothesis that adding intravenous ketamine to a postoperative regimen of intravenous opioids for postoperative pain will improve pain relief in this subset of patients.

Official Title
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Hydromorphone PCA or Hydromorphone PCA With Ketamine for Acute Postoperative Pain Relief in Opioid-Dependent Chronic Pain Patients

Conditions
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Postoperative Pain

Intervention / Treatment
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* Drug: Ketamine
* Drug: Placebo
* Drug: Hydromorphone PCA


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Chronic pain > 6 months Long term use of opioids Major surgery Exclusion Criteria: Use of regional anesthetic techniques No need for intravenous (IV) patient controlled analgesia (PCA) after surgery

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Single Group Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Ketamine<br>Participants received postoperative hydromorphone patient-controlled analgesia (PCA) and continuous ketamine (0.2 mg/kg/hour). Ketamine is being compared to the use of placebo, in addition to intravenous opioids, for postop pain control in opioid dependent patients who undergo major surgery. | Drug: Ketamine<br>* Intravenous (IV) ketamine 0.2 mg/kg/hr for 24-48 hours postoperatively.<br>Drug: Hydromorphone PCA<br>* Intravenous hydromorphone PCA<br>|
| Placebo Comparator: Placebo<br>Participants received postoperative hydromorphone PCA and continuous ketamine-matching placebo (infusion of saline). | Drug: Placebo<br>* Patients who received ketamine-matching placebo were given saline infusions<br>Drug: Hydromorphone PCA<br>* Intravenous hydromorphone PCA<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Average Postoperative Pain Score | Postoperative pain scores were collected once per day during morning rounds for the preceding 24 hours. Participant were asked to provide pain scores for worst, average, and least pain using the 11-point Numerical Rating Scale (NRS), where 0 represents the absence of pain and 10 is worst possible pain. The average postoperative pain score for each treatment arm is reported. | Participants were followed for the duration of hospital stay, an average of approximately 3 days. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Worst Postoperative Pain Score | Postoperative pain scores were collected once per day during morning rounds for the preceding 24 hours. Participant were asked to provide pain scores for worst, average, and least pain using the 11-point Numerical Rating Scale (NRS), where 0 represents the absence of pain and 10 is worst possible pain. The average worst postoperative pain score for each treatment arm is reported. | Participants were followed for the duration of hospital stay, an average of approximately 3 days. | 
| Least Postoperative Pain Score | Postoperative pain scores were collected once per day during morning rounds for the preceding 24 hours. Participant were asked to provide pain scores for worst, average, and least pain using the 11-point Numerical Rating Scale (NRS), where 0 represents the absence of pain and 10 is worst possible pain. The average least postoperative pain score for each treatment arm is reported. | Participants were followed for the duration of hospital stay, an average of approximately 3 days. | 
| 24-Hour Postoperative Opioid Use | Opioid use is defined as the total milligrams of hydromorphone plus other home or oral opioid used per 24 hours, converted to oral morphine equivalents. | For 24 hours following surgery | 
| Number of Participants With Treatment Related Adverse Events (AEs) | Participants were asked to complete a Side Effects Checklist to assess for any unwanted side effects (AEs) of drugs that were administered. The determination of whether or not an AE was treatment related was at the discretion of the Investigator. | Participants were followed for the duration of hospital stay, an average of approximately 3 days. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Ketamine, Postoperative pain, Opioid dependent patients, Acute pain control