Avalia？？o da analgesia pós-operatória em artroplastias de quadril com morfina por via subaracnoidea associada ao bloqueio "3 em 1": estudo aleatório e encoberto

background and objectives: pain worsens postoperative morbidity and mortality, especially in surgeries such as hip replacement arthroplasty. this study aimed at evaluating postoperative pain, opioid consumption, complications and motor block for more than 6 hours in patients receiving subarachnoid morphine associated or not to "3 in 1" blockade for hip replacement arthroplasty. method: randomized, double-blind clinical trial with 49 patients submitted to elective hip replacement arthroplasty who were distributed in two groups: 24 patients in group 1 (g1) and 25 patients in group 2 (g2). both groups received spinal anesthesia with subarachnoid morphine and "3 in 1" blockade was associated in group 2. pain, number of rescue opioid doses, incidence of pruritus, nausea and vomiting, and motor block in lower limbs for more than 6 hours were evaluated in the postoperative period. results: thirteen g1 patients (54.2%) reported pain intensity ≥ 1, while in g2 pain was reported by 6 patients (24%) with statistically significant difference (p = 0.029). no patient reported severe pain. tramadol, used as rescue opioid, was administered to 25% g1 patients and 8% of g2 patients, without significant difference (p = 0.11). there has been no difference between groups in pruritus, nausea, vomiting and motor block for more than 6 hours. conclusion: the association of subarachnoid morphine and "3 in 1" blockade decreases the incidence of pain in patients submitted to hip replacement arthroplasty without increasing the incidence of complications.