Análisis de la eficacia clínica de la ketamina en el dolor agudo postoperatorio

Resumen

ESTUDIO A: Effects of Ketamine on Postoperative Pain After Remifentanil-BasedAnesthesia for Major and Minor Surgery in Adults: A Systematic Review and Meta-Analysis García-Henares JF, Moral-Munoz JA, Salazar A, Del Pozo E. Effects of Ketamine on Postoperative Pain After Remifentanil-Based Anesthesia for Major and MinorSurgery in Adults: A Systematic Review and Meta-Analysis. Front Pharmacol. 2018; 9:921. doi: 10.3389/fphar.2018.00921. Ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, has been postulated as an adjuvant analgesic for preventing remifentanil-induced hyperalgesia after surgery. This systematic review and meta-analysis aims to assess the effectiveness of ketamine [racemic mixture and S-(+)-ketamine] in reducing morphine consumption and pain intensity scores after remifentanil-based general anesthesia. We performed a literatura search of the PubMed, Web of Science, Scopus, Cochrane, and EMBASE databases in June 2017 and selected randomized controlled trials using predefined inclusion and exclusion criteria. To minimize confounding and heterogeneity, studies of NMDA receptor antagonists other than ketamine were excluded and the selected studies were grouped into those assessing minor or major surgery. Methodological quality was evaluated with the PEDro and JADA scales. The data were extracted and meta-analyses were performed where possible. Twelve RCTs involving 156 adults who underwent minor surgery and 413 adults who underwent major surgery were included in the meta-analysis. When used as an adjuvant to morphine, ketamine reduced postoperative morphine consumption in the first 24 h and postoperative pain intensity in the first 2 h in the minor and major surgery groups. It was also associated with significantly reduced pain intensity in the first 24 h in the minor surgery group. Time to the first rescue analgesia was longer in patients who received ketamine and underwent major surgery. No significant differences in the incidence of ketamine-related adverse effects were observed among patients in the intervention group and controls. This systematic review and meta-analysis show that low-dose (0.5 mg/kg for iv bolus or 5 μg/kg/min for iv perfusion) of ketamine reduces postoperative morphine consumption and pain intensity without increasing the incidenceof adverse effects Keywords: remifentanil, ketamine, minor surgery, mayor surgery, NMDA antagonist, meta-analysis ESTUDIO B: Efficacy of Ketamine plus Morphine in Patient-Controlled Analgesia in Spinal Arthrodesis. A Randomized Comparison with Morphine Background: Ketamine, an N-methyl-D-aspartate receptor antagonist, has been postulated as adjuvant analgesic in postoperative multimodal analgesia regimens at sub-anesthetic doses. This study was mainly undertaken to assess the morphine sparing effects of ketamine added to morphine-based iv Patient-Controlled Analgesia (PCA), in patients undergoing elective lumbar spinal surgery. Methods: This was a randomized, double-blinded, parallel-group, drug-controlled, clinical trial. Fifty-two patients received postoperative analgesia (iv PCA) with morphine + ketamine (MK group) or morphine + saline (MO group) and were observed for 72 h postoperatively. The primary outcome was morphine consumption. Secondary outcomes were postoperative nausea and vomiting (PONV), pain intensity at rest and on mobilization, and neuropathic pain score. Results: Twenty-two patients in each group completed the study. The intention-to-treat adjusted analysis for primary outcome showed that patients in MK group had a significant decrease (P < 0.01) in cumulative morphine doses respect MO group. The analysis of secondary outcomes showed that the incidence of PONV moderate, severe and uncontrollable was significantly lower in the MK group respect to MO group at 24 h postoperatively. VAS scores at rest and on mobilization were lower in MK group (P < 0.035) at all times registered. The groups had no differences in pain DETECT scores. Conclusions: Low doses of ketamine as an adjunct to a morphine-based iv PCA reduced the consumption of morphine, the intensity of pain and the incidence of high intensity PONV in the immediate (72 h) postoperative period.