Eficacia analgésica de una dosis única de dexametasona perineural en el bloqueo ecoguiado del nervio femoral en cirugía de prótesis total de rodilla

Abstract

BACKGROUND. To date, there is no study comparing the effect of perineural dexamethasone as adjuvant to local anaesthetics to prolong the duration of the femoral nerve block. OBJETIVE: To evalúate the effectiveness and safety of the analgesia provided by dexamethasone used at perineural level in the femoral nerve block after total knee replacement with the one used at intravenous level and with a control group. METHODS. A prospective, randomised, double-blind study with two control groups has been designed. 81 patients were divided in 3 groups according two drugs combinations to perform the femoral nerve block: 1) 0.5% ropivacaine with 8 mg dexamethasone IV, 2) 0.5% ropivacaine with 8 mg perineural dexamethasone 3) control group (0.5% ropivacaina). The primary outcome was time of duration of the sensitive-analgesic block of the femoral nerve block. The secondary outcomes included pain according to VAS scale, patient satisfaction, morphine consumption, night rest, incidence of complications and side effects. RESULTS. Baseline characteristics were similar in the tree groups. Analgesia duration was significantly higher (p<0.0001) in the group with perineural dexamethasone (mean 1152.2 min, 95% Cl 756.9-1547.6) in comparison with the control group (mean 186 min, 95% Cl 81.2-292) and the group with dexamethasone IV (mean 159.4 min, 95% Cl 109.8-209). Postoperative pain measured according the VAS scale morphine consumption and side effects were also lower in perineural dexamethasone group. CONCLUSIONS. Perineural dexamethasone prolongs sensitive block from single dose of femoral nerve block using ropivacaine. It also provides a better analgesia and patient satisfaction with less side effects.