INFLUENCE OF TIMING ON THE ANALGESIC EFFECT OF INTRAVENOUS KETOROLAC AFTER ORTHOPEDIC-SURGERY

This study evaluated the pre-emptive analgesic effect of intravenous (i.v.) ketorolac (KET) for total hip replacement (THR). Sixty patients who underwent surgery for THR under general anesthesia were randomly allocated to 3 groups. Two i.v. injections were administered: one before induction and one after surgery. The patients were studied prospectively in a double-blind manner. The control group (CONT; n = 20) received 2 mi of normal saline (NS) for both injections. The pre-operative KET group (PRE; n = 20) received 60 mg of KET and then 2 mi of NS. The postoperative KET group (POST; n = 20) received 2 mi of NS and then 60 mg of KET. General anesthesia was standardized with a intra-operative cumulated dose of fentanyl limited to 4 mu g/kg. In the recovery room (RR), pain was controlled with an i.v. titration of morphine; thereafter, on the surgical ward, patients used a patient-controlled analgesia (PCA) pump (Abbott). Pain was evaluated with a visual analogue scale (VAS) at rest and movement in the RR, then every hour for 6 h and every 6 h for 2 days. The side effects monitored were: sedation, respiratory depression, nausea, perioperative bleeding. The patients and surgery were similar for the 3 groups. Upon arrival in the RR, VAS scores taken at rest and at movement were lower for the PRE group than for the CONT and POST groups. Otherwise, VAS scores were similar in all 3 groups. The cumulative dose of morphine in the PRE group was lower than that for the CONT and POST groups from 0 to 6 h. However, the hourly consumption of morphine after titration was similar in all 3 groups for the entire study. Four patients, 2 in the PRE and 2 in the POST group had abnormal bleeding. In this study 60 mg of pre-operative KET had greater analgesic effect than the same dose administered at skin closure. This beneficial effect was important in the immediate postoperative period but was not sustained with time.