Extrapolating beyond the Data

To the Editor:-We read with interest the report by Norman et al. on preemptive analgesic effect of ketorolac. 1 The authors observed that for 48 patients undergoing ankle fracture surgery that 30 mg of intravenous ketorolac administered before tourniquet inflation offered a better analgesia than after tourniquet inflation at 2 and 4 h after surgery. Can we conclude that it is preemptive analgesia? The effect of ketorolac is mainly peripheral and the tourniquet inflation is probably an adequate technique to compare pre-and postoperative administration. However, the benefit between the two administrations is shortlived (4 h after surgery) and totally compatible with the effect of a single dose of ketorolac. Because preemptive analgesia has to do with limitation of nervous system sensitization, 2 these results (similar to previous one 3,4 ) do not support a preemptive analgesic effect. Rather, they suggest that preoperative administration of nonsteroidal antiinflammatory drugs may reduce or delay the development of peripheral inflammation and therefore improve immediate postoperative analgesia. This effect is transient and vanishes a few hours after surgery, which is totally different from preemptive analgesia observed after some studies using ketamine 5 or local anesthetic. 6,