ObjectiveTo systematically evaluate the efficacy of high-flow nasal cannula oxygen therapy (HFNC) versus standard nasal cannula oxygen therapy (SNC) in improving hypoxemia during non-intubated general anesthesia (NIGA) in obese patients. MethodsPubMed, Embase, Web of Science, The Cochrane Library, Wanfang Data, CNKI, VIP, and CBM were searched from database inception to March 2026. Two researchers screened the the literature, extracted data, and evaluated the risk of bias in the included studies independently. RevMan 5.4, Stata 15.1 and TSA 0.9.5.10 beta software were used for the meta-analysis and trial sequential analysis. Results A total of 13 RCTs were included, including 1 971 patients. The meta-analysis results showed that compared with the SNC group, the HFNC group reduced the incidence of hypoxemia (RR=0.19, 95%CI 0.07~0.48, P=0.000 4) and mask usage rate (Peto-OR=0.11, 95%CI 0.07~0.17, P<0.000 01), shortened the diagnosis and treatment operation time (MD=?1.78, 95%CI ?2.90~?0.65, P=0.002), but there was no statistically significant difference in the incidence of nasopharyngeal adverse reactions between the two groups (RR=0.55, 95%CI 0.19~1.62, P=0.28). Subgroup analysis showed that there was no statistically significant difference in the incidence of hypoxemia between the HFNC group (under non-pure oxygen conditions) and the SNC group (RR=0.89, 95%CI 0.53~1.50, P=0.67). ConclusionsHFNC can reduce the occurrence of hypoxemia and mask intervention during NIGA in obese patients, however, its effect may differ according to the FiO2 setting. Due to the limitations of the included research quality, more high-quality studies are needed to verify the above conclusions.
Objective Tolerogenic DCs (Tol-DCs), a group of cells with imDC phenotype, can stably induce T cells low-reactivity and immune tolerance. We systematically reviewed the adoptive transfusion of Tol-DCs induced by different ways to prolong cardiac allograft survival and its possible mechanism. Method MEDLINE (1966 to March 2011), EMbase (1980 to March 2011), and ISI (inception to March 2011) were searched for identification of relevant studies. We used allogeneic heart graft survival time as endpoint outcome to analyze the effect of adoptive transfusion of Tol-DC on cardiac allograft. By integrating studies’ information, we summarized the mechanisms of Tol-DC in prolonging cardiac grafts. Results Four methods were used to induce Tol-DC in all of the 44 included studies including gene-modified, drug-intervened, cytokine-induced, and other-derived (liver-derived amp; spleen-derived) DCs. The results showed that all types of Tol-DC can effectively prolong graft survival, and the average extension of graft survival time for each group was as follows: 22.02 ± 21.9 days (3.2 folds to control group) in the gene modified group, 25.94 ± 16.9 days (4.3 folds) in the drug-intervened groups, 9.00 ± 8.13 days (1.9 folds) in the cytokine-induced group, and 10.69 ± 9.94 days (2.1 folds) in the other-derived group. The main mechanisms of Tol-DCs to prolong graft survival were as follows: a) induceT-cell hyporeactivity (detected by MLR); b) reduce the effect of cytotoxic lymphocyte (CTL); c) promote Th2 differentiation; d) induce Treg; e) induce chimerism. Conclusion For fully MHC mismatched allogeneic heart transplant recipients of inbred mouse, adoptive transfusion of Tol-DC, which can be gene-modified, drug-intervened, cytokine-induced, spleen-derived or liver-derived, can clearly prolong the survival of cardiac allograft or induce immune tolerance. Gene-modified and drug-induced Tol-DC can prolong graft survival most obviously. Having better reliability and stability than drug-induction, gene-modification is the best way to induce Tol-DCs at present. One-time intravenous infusion of 2 × 106 Tol-DC is a simple and feasible way to induce long-term graft survival. Multiple infusions will prolong it but increase the risk and cost. Adoptive transfusion of Tol-DC in conjunction with immunosuppressive agents may also prolong the graft survival time.