Impact of neuromuscular blockade depth on postoperative systemic cytokine release: a systematic review and meta-analysis.

backgroundDeep neuromuscular blockade (NMB) optimizes surgical conditions, particularly during laparoscopic procedures. However, its effects on systemic cytokines associated with anesthesia-related complications, including postoperative delirium and cognitive dysfunction, remain unclear. In this review, we quantified the impact of deep NMB on serum cytokine levels.

methodsPubMed, EMBASE, CENTRAL, CINAHL, Scopus, Web of Science, and Google Scholar databases were searched to identify randomized controlled trials (RCTs) evaluating serum cytokine levels in surgical patients under deep or moderate NMB.

resultsEight RCTs, including 661 patients undergoing laparoscopic and orthopedic surgeries, met the inclusion criteria. Immediately postoperatively, meta-analysis suggested a potential reduction in tumor necrosis factor-α (TNF-α, standardized mean difference: -0.46, 95% CI [-0.87 to -0.06], P = 0.03), with no significant differences in interleukin-1β (IL-1β) or interleukin-6 (IL-6) levels. At 24-h and 48-h postoperatively, no significant differences were observed in IL-1β, IL-6, TNF-α, or C-reactive protein levels. Meta-regression analysis indicated that inhalational anesthesia was associated with high IL-1β (estimate = 1.2135, 95% CI [0.5107-1.9162], P < 0.01) and TNF-α levels (estimate = 0.6271, 95% CI [0.0544-1.1997], P = 0.032) immediately postoperatively; however, younger patients exhibited elevated IL-1β levels under moderate NMB at 24-h postoperatively (estimate = 0.0242, 95% CI [0.0065-0.0419], P < 0.01).

conclusionsDeep NMB may be associated with reduced TNF-α levels immediately postoperatively. Inhalational anesthesia and younger age may contribute more to higher serum cytokine levels compared with total intravenous anesthesia and older age, respectively, suggesting a potential immunomodulatory effect of deep NMB. Further studies should clarify its clinical relevance.