ESRA19-0592 Intrathecal morphine as postoperative analgesia for knee arthroplasty: randomized and controlled study of pain control and side effects

Background and aims Intrathecal morphine (ITM) provides analgesia for 12 to 24 hours after multiple types of surgery, using single shot doses. Knee arthroplasty is associated to severe pain and is usually performed under spinal anesthesia. Methods 38 patients with ages between 53 and 87 years, ASA II and III, proposed for knee arthroplasty underwent spinal anesthesia with hyperbaric bupivacaine 0,5%, 0,025 mg of sufentanil and 0,2 mg of morphine. Post-surgery 48h analgesia were stratified into two groups: A, epidural analgesia with local anesthetic (balloon of ropivacaine 1 mg/ml, 2cc/h) and B, intravenous analgesia with tramadol 400 mg and droperidol 1,25 mg at 2cc/h perfusion. All patients received multimodal analgesia with paracetamol and AINEs together with triple nausea and vomiting prophylaxis. The efficacy of analgesia, side effects incidence and patient satisfaction was compared with a control group where no ITM was administered. Results This study demonstrated ITM in a 0,2 mg dose provides effective pain control during the first 24h in rest for both groups; it fails to prove pain control during mobilization in the B group (A: 100% vs 71% of control/B: 65% vs 72% of control). High prevalence of pruritus (13–25%) and nausea and vomiting (7–25%) in both groups.60 to 75% of patients reported good and excellent pain relief. There seems to be no significant difference between epidural and intravenous analgesia; however, there are not enough registers. Conclusions Spinal analgesia combined with ITM (0,2 mg) provides an effective pain relief for knee arthroplasty, especially if coupled with epidural perfusion of local anesthetic. ITM 0,2 mg is still associated with a high prevalence of side effects.