Evaluation of preemptive effect of epidural S(+)-ketamine for hysterectomy: plasmatic concentrations of interleukins.

Background and Objectives: Some studies showed that ketamine inhibits the production of cytokines. The objective of this study was to evaluate the preemptive analgesic effect of epidural S(+)-ketamine in hysterectomy and plasmatic cytokines (IL-6, TNF-α and IL-10).
Method: A double-blinded study with 29 patients was conducted. Patients in Group 1 received 13 mL of 0.25% bupivacaine with 25mg of S(+)- ketamine 30 minutes before surgical incision and 15 mL of saline solution via the epidural route 30 minutes after. Patients in Group 2 received 15 mL of saline solution 30 minutes before the surgical incision, followed by 13 mL of 0.25% bupivacaine with 25mg of S(+)-ketamine 30 minutes after. Postoperative analgesia was made with epidural bupivacaine and fentanyl. Dipyrone 1 g was used whenever required. The following paramenters were evaluated: concentration of cytokines, intensity of pain, time of first request of analgesic and total quantity of analgesic used.
Results: Time for the first request for analgesics was 61.5 minutes in Group 1 and 69.0 in Group 2, without difference between these groups. There was no difference for total dose of fentanyl used in Group 1 (221.4 μg) and Group 2 (223.3 μg). A similar analgesic effect was obtained in both groups, except in T12 (Group 1 = 2.4±3.2; Group 2 = 5.5±3.4). No differences in concentration of cytokines were observed.
Conclusions: The epidural injection of 25mg S(+)-ketamine before incision reduced the pain intensity only 12 hours after surgical incision and did not alter concentration of cytokines.
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