Could Wound Instillation Provide an Efficient Analgesia Comparable to That Provided by PECS-II Block for Modified Radical Mastectomy Using Ketamine-Bupivacaine Combination? A Pilot Study.

Background and aim: In the light of the abundance of various analgesic methods available for analgesia following modified radical mastectomy (MRM) (pharmacological or interventional), we aimed to try a very simple technique using a drug combination (ketamine-bupivacaine) through wound instillation and to compare it to the reputable PECS-II block using the same drug combination. We hypothesized that, with this drug combination, local instillation may achieve a comparable, long lasting, analgesia for almost 48 hours, with less costly, and simple method.

Patients and methods: Sixty women scheduled to undergo MRM participated in this study. Patients were randomized to have either; ultrasound-guided, modified PECS block (PECS group), or instillation of analgesics into the surgical wound (local instillation group). In both groups, we used 1 mg/kg ketamine HCL plus 0.25% bupivacaine HCL in a 30 mL volume. Total consumption of rescue morphine, time to 1^st analgesic request, numerical rating scale (NRS), hemodynamic effects were recorded over 48 hours postoperatively. In addition, the time required to perform either technique and possible side effects were recorded.

Results: Total consumption of rescue morphine, first analgesic request, pain scores, showed no statistically significant differences in both groups; the local instillation procedure required a statistically significant shorter time to perform than the PECS procedure. None of the groups showed significant differences in the incidence of adverse effects.

Conclusion: Local wound instillation provided a comparable analgesia to PECS-II block following modified radical mastectomy. Ketamine-bupivacaine combination prolonged analgesia for almost 2 days.