The effect of opioid-free anesthesia using lidocaine on the level of inflammatory markers in thoracic patients in the intra- and postoperative period: prospective randomized study

BACKGROUND: A pressing issue still remains the reduction of opioid analgesic dosages as a part of anesthesiological support, due to the wide range of complications they cause. An alternative to opioids is opioid-free anesthesia, including the use of lidocaine, which can influence the activity of cytokines, which reflects the advisability of its use in order to prevent an increase in the content of inflammatory markers in the postoperative period. In the domestic and foreign scientific literature, the issue of the dependence of the level of inflammatory markers on the use of non-opioid anesthesia in comparison with opioid anesthesia is relatively little studied, especially in the field of thoracic surgery.

AIM: Our aim was to conduct a comparative analysis of the content of cytokines as markers of inflammation during anesthesia using intravenous lidocaine infusion, intravenous fentanyl infusion and a combination of intravenous fentanyl and epidural anesthesia.

MATERIALS AND METHODS: A single-center, prospective, randomized study was conducted among 90 patients with a verified diagnosis of lung cancer who underwent video-assisted thoracoscopic (Vlobectomy. Depending on the method of anesthesia, patients were divided into 3 groups of 30 people: in the 1st group, lidocaine was administered, in the 2nd group, fentanyl was administered, and in the 3rd group, fentanyl was administered in combination with epidural anesthesia. The main result of the study was the assessment of the concentration of cytokines in the blood serum (interleukins - IL-2, IL-6, IL-10, as well as tumor necrosis factor α — TNF-α) using an enzyme-linked immunosorbent assay. An additional outcome was a laboratory assessment of the concentrations of glucose and cortisol in the blood serum (the analysis of these indicators was performed to assess the adequacy of anesthetic management in the intraoperative period). Statistical analysis of the results was carried out using the Python v.3.0 programming language in Jupiter Notebook.

RESULTS: Analysis of IL-6 content showed a significant difference in favor of group 1 already at the end of the operation (H=10.366691, p=0.0056); 1 day after the end of the operation, the difference in the indicator between the groups increased (H = 65.603614 , p <0.001) with the lowest value in group 1. The level of TNF-α at the end of the operation did not reflect significant differences between the groups (H=0.578241, p=0.748922), however, after 24 hours, changes made it possible to note positive dynamics also in group 1 (H=12.928289 , p=0.001558). Similar results were recorded for IL-10 [(H=1.325812, p=0.515352) and (H=9.11072, p=0.010511)] and IL-2 [(H=5.185739, p=0.074805) and (H=23.420171, p=0.000008)], respectively.

CONCLUSION: Our results showed that opioid-free anesthesia based on intravenous lidocaine infusion positively correlates with serum concentrations of IL-2, IL-6, IL-10, and TNF-α in patients undergoing thoracic surgery. Serum levels of these cytokines may be indicators of inflammatory responses and may have clinical implications for selecting appropriate anesthesia for patients with lung cancer. In addition, data regarding IL-2 are new and may be associated with tumor progression and the occurrence of distant metastases.