Abstract Background Tumor Necrosis Factor-α (TNF-α) and Interleukin-1β (IL-1β) are among the cytokines released secondary to the surgical stress response. The objective of this study was to investigate the effect of a Transversus Abdominis Plane (TAP) block on postoperative pain and its immunomodulatory activity through proinflammatory cytokines. Methods TAP (study group; n = 40) or p-TAP (placebo group; n = 40). Patients in the TAP group underwent an Ultrasound (US) guided unilateral TAP block using 20-cc 0.5% bupivacaine solution. Patients in the p-TAP group underwent a sham block using 20-cc isotonic solution. The TNF-α and IL-1β levels were measured three times at preoperative hour-0 and postoperative hours 4 and 24. Visual Analog Scale (VAS) scores were recorded at 0-hours, 30-minutes, 4-hours, and 24-hours. Analgesic use within the first 24-hours following surgery was monitored. Results The postoperative VAS score was decreased in the TAP group at all time points (0, 4, and 24 hours), and the differences between groups were statistically significant (p < 0.001 for all comparisons). In the TAP group, the TNF-α and IL-1β levels at 4 and 24 hours post operation were significantly lower than the preoperative levels (p < 0.001 for all comparisons). Conclusion The TAP block for pre-emptive analgesia enabled effective hemodynamic control during the intraoperative period, provided effective pain control in the postoperative period, and decreased inflammation and surgical stress due to the decreased levels of the proinflammatory cytokines TNF-α and IL-1β in the first postoperative 24 hours, indicating immunomodulatory effect.

RESUMO JUSTIFICATIVA E OBJETIVOS: Comparar as características do bloqueio e os efeitos clínicos da adição de dextrose às soluções de levobupivacaína em diferentes concentrações para proporcionar raquianestesia unilateral em cirurgia de extremidade inferior. MÉTODOS: Estudo prospectivo, randômico e duplo-cego conduzido com 75 pacientes, estado físico ASA I-II, programados para artroplastia unilateral total do joelho. Os pacientes foram divididos em três grupos: no Grupo-I, 60 mg de dextrose foram adicionados a 7,5 mg de levobupivacaína a 0,5%; no Grupo II, 80 mg e no Grupo III, 100 mg. A raquianestesia foi aplicada ao paciente posicionado em decúbito lateral, com o lado operado abaixo, e o paciente foi mantido em posição durante 10 minutos. RESULTADOS: O tempo para o bloqueio sensorial atingir o nível T12 foi mais lento no Grupo-I do que nos grupos II e III (p < 0,05,p < 0,00). O tempo de recuperação total do bloqueio sensorial foi de 136 minutos no Grupo-I, 154 minutos no Grupo-II e 170 minutos no Grupo III. As diferenças foram estatisticamente significativas (p < 0,05). A média da duração do bloqueio motor foi de 88 minutos no Grupo-I, 105 minutos no Grupo-II e 139 minutos no Grupo-III e as diferenças foram estatisticamente significativas (p< 0,05). O tempo de micção foi significativamente menor no Grupo-I do que nos outros grupos (p < 0,00). CONCLUSÕES: Os resultados do estudo mostraram que, junto com um aumento da densidade, a duração dos bloqueios sensorial e motor foi prolongada. Pode-se concluir que uma concentração 30 mg mL-1 de dextrose adicionada a 7,5 mg de levobupivacaína é suficiente para proporcionar raquianestesia unilateral para artroscopia do joelho em regime ambulatorial.

ABSTRACT BACKGROUND AND OBJECTIVES: The aim of the study was to compare the block characteristics and clinical effects of dextrose added to levobupivacaine solutions at different concentrations to provide unilateral spinal anaesthesia in lower extremity surgery. METHODS: This prospective, randomised, double-blind study comprised 75 ASA I-II risk patients for whom unilateral total knee arthroscopy was planned. The patients were assigned to three groups: in Group I, 60 mg dextrose was added to 7.5 mg of 0.5% levobupivacaine, in Group II, 80 mg and in Group III, 100 mg. Spinal anaesthesia was applied to the patient in the lateral decubitus position with the operated side below and the patient was kept in position for 10 min. RESULTS: The time for the sensorial block to achieve T12 level was slower in Group I than in Groups II and III (p < 0.05, p< 0.00). The time to full recovery of the sensorial block was 136 min in Group I, 154 min in Group II and 170 min in Group III. The differences were statistically significant (p < 0.05). The mean duration of the motor block was 88 min in Group I, 105 min in Group II, and 139 min in Group III and the differences were statistically significant (p < 0.05). The time to urination in Group I was statistically significantly shorter than in the other groups (p < 0.00). CONCLUSIONS: The results of the study showed that together with an increase in density, the sensory and motor block duration was lengthened. It can be concluded that 30 mg mL-1 concentration of dextrose added to 7.5 mg levobupivacaine is sufficient to provide unilateral spinal anaesthesia in day-case arthroscopic knee surgery.