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.
Background: N-methyl D-Aspartate (NMDA) receptors seem to be responsible for pain memory and their blockade can contribute significantly in prevention of pain. This study was conducted to evaluate the preventive effect of small dose of ketamine, a NMDA receptor blocker, given before skin incision in renal surgery, with the aim to compare analgesic efficacy, intra operative and post-operative side effects. Materials and Methods: In a prospective double-blind study, 60 American Society of Anesthesiologists (ASA) risk I and II adult patients scheduled for elective open renal surgeries by flank incision were randomly divided in two groups. Ketamine group (group K) received ketamine 0.15 mg/kg intravenously, 30 minute before start of surgery followed by infusion of ketamine 2 mcg/kg/min till start of skin closure. Control group (group C) received normal saline in place of ketamine. Both groups received morphine 0.15 mg/ kg i.v. at the time of skin closure. The analgesic efficacy was judged by visual analogue scale (VAS) at rest and on movement, time to first analgesic and morphine consumption in 24 hours. Opioid or ketamine related side effects were also recorded. Results: Patients in ketamine group had significantly lower VAS score, longer time to first analgesic (21.6 ± 0.12 Vs 3.8 ± 0.7 hrs), and lower morphine consumption (5.8 ± 1.48 Vs 18.1 ± 1.6 mg) in 24 hours. There were no demonstrable side effects related to ketamine in group K whereas incidence of nausea and vomiting was higher in group C. Conclusion: Our results demonstrate that small dose of ketamine decreases post-operative pain, reduces morphine consumption, and delays patients request for analgesia beyond the clinical duration of action of ketamine after open renal surgery.
BACKGROUND: In literature, there is controversy on the use of ketamine for management of postoperative pain. The aim of the present study was to evaluate the efficacy of pre-incisional intravenous or subcutaneous infiltration of ketamine on postoperative pain relief after open cholecystectomy. METHODS: One hundred twenty patients, aged 18–60 years, scheduled for open cholecystectomy was enrolled in this randomized, double-blind, placebo-controlled study. Patients were divided into four groups of 30 each and received subcutaneous infiltration of ketamine 1 mg/kg (group KS1), subcutaneous infiltration of ketamine 2 mg/kg (group KS2), intravenous ketamine 1 mg/kg (group KI), or subcutaneous infiltration of normal saline 20 mL (group C) before surgery. Visual analog scale (VAS) values and analgesic consumption were evaluated for 24 hours after operation. RESULTS: VAS scores were significantly lower at arrival to the postanesthesia care unit, 15 and 30 minutes in Group KS1, Group KS2, and Group KI compared with Group C (<i>P</i> < 0.05). In Group KS2, VAS scores were significantly lower than Group KS1 (<i>P</i> < 0.05). Postoperative VAS scores were significantly lower at 1, 2, 3, 4, 8, 12, and 24 hours after operation in Group KS1, Group KS2, and Group KI compared with Group C (<i>P</i> < 0.05). In Group KS2, VAS scores were significantly lower than Group KS1 (<i>P</i> < 0.05). CONCLUSION: A 2 mg/kg dose of subcutaneous infiltration ketamine or 1 mg/kg dose of intravenous ketamine given at approximately 15 minutes before surgery provides an adjunctive analgesia during 24 hours after surgery in patients undergoing cholecystectomy surgery. (PsycInfo Database Record (c) 2022 APA, all rights reserved)
OBJECTIVE: This study aims to demonstrate the analgesic efficacy and opioid-sparing effect of low dose ketamine in patients with preoperative narcotic intake undergoing major spine surgery. DESIGN: The study used a prospective, randomized, double-blinded, and placebo-controlled clinical trial. Settings and PATIENTS: We evaluated the analgesic efficacy and safety of low dose IV ketamine infusion after major spine surgery in patients with preoperative narcotic analgesic intake. Ketamine group received IV ketamine infusion (2 µg/kg/min) and saline group received saline intraoperatively and the first 24 hours postoperatively. In addition, all patients received IV patient-controlled hydromorphone and epidural bupivacaine. Outcome Measures: Pain scores, narcotic requirement, and side effects were compared between the groups for 48 hours postoperatively. RESULTS: Thirty patients completed the study (N = 15 in each group). No difference in pain scores at rest and movement was noted between the groups (<i>P</i> > 0.05). Patients in ketamine group received 40.42 ± 32.86 mg IV hydromorphone at 48 hours compared with 38.24 ± 26.19 mg in saline group (<i>P</i> = 0.84). Central nervous system side effects were observed in five (33%) ketamine group patients compared with nine (60%) in saline group (<i>P</i> = 0.29). CONCLUSION: The addition of IV very low dose ketamine infusion regimen did not improve postoperative analgesia. Side effects were not increased with low dose ketamine. (PsycInfo Database Record (c) 2021 APA, all rights reserved)
BACKGROUND:: Ketamine is an N-methyl-d-aspartate receptor antagonist that has been shown to be useful in the reduction of acute postoperative pain and analgesic consumption in a variety of surgical interventions with variable routes of administration. Little is known regarding its efficacy in opiate-dependent patients with a history of chronic pain. We hypothesized that ketamine would reduce postoperative opiate consumption in this patient population. METHODS:: This was a randomized, prospective, double-blinded, and placebo-controlled trial involving opiate-dependent patients undergoing major lumbar spine surgery. Fifty-two patients in the treatment group were administered 0.5 mg/kg intravenous ketamine on induction of anesthesia, and a continuous infusion at 10 mug kgmin was begun on induction and terminated at wound closure. Fifty patients in the placebo group received saline of equivalent volume. Patients were observed for 48 h postoperatively and followed up at 6 weeks. The primary outcome was 48-h morphine consumption. RESULTS:: Total morphine consumption (morphine equivalents) was significantly reduced in the treatment group 48 h after the procedure. It was also reduced at 24 h and at 6 weeks. The average reported pain intensity was significantly reduced in the postanesthesia care unit and at 6 weeks. The groups had no differences in known ketamine- or opiate-related side effects. CONCLUSIONS:: Intraoperative ketamine reduces opiate consumption in the 48-h postoperative period in opiate-dependent patients with chronic pain. Ketamine may also reduce opioid consumption and pain intensity throughout the postoperative period in this patient population. This benefit is without an increase in side effects.
