目的  探究高截留(high cut-off,HCO)膜连续性静脉-静脉血液透析滤过(continuous venovenous hemodiafiltration,CVVHDF)对脓毒症患者免疫功能、炎症介质水平及器官功能的影响。 方法  选取2024年1月—2025年10月包头市中心医院重症医学科收治的需要行连续性肾脏替代治疗(continuous renal replacement therapy,CRRT)的脓毒症(包括脓毒症休克)患者开展研究，信封随机法分为观察组(HCO组)、对照组。收集CRRT治疗前及治疗24 h后血液中T淋巴细胞亚群、白细胞介素-6(interleukin-6,IL-6)、降钙素原(procalcitonin,PCT)及急性生理学和慢性健康状况评价Ⅱ(acute physiology and chronic health,APACHEⅡ)、序贯器官衰竭估计评分(sequential organ failure assessment,SOFA)、28 d死亡率及死亡原因。 结果  本研究共纳入80例患者。治疗24 h后，HCO组CD3＋%、CD4＋%、CD4＋/CD8＋高于对照组(Z=-2.916、-2.358、-3.873，P值分别为0.004、0.018、＜0.001)，CD8＋%、 IL-6、SOFA低于对照组(Z=-3.387、-1.963、-3.345，P=0.001、0.049、0.001)，APACHEⅡ低于对照组(t=   -4.163,P＜0.001)，IL-6下降率高于对照组(Z=-2.858,P=0.004)，2组PCT、PCT下降率比较差异无统计学意义(Z=-1.179、-1.010，P=0.238、0.312)，2组患者28 d死亡率、死亡原因比较差异均无统计学意义(P=0.522、0.952)。 结论  高截留膜CVVHDF通过有效清除炎症介质、调节免疫稳态，有助于改善脓毒症患者的器官功能。

Objective  To explore the effects of high cut-off (HCO) membrane continuous venovenous hemodiafiltration  (CVVHDF) on immune function, inflammatory mediator level and organ function in patients with sepsis, and to provide a basis for optimizing the treatment strategy of sepsis.  Methods  Patients with sepsis (including septic shock) requiring continuous renal replacement therapy (CRRT) admitted to the Department of Critical Care Medicine, Baotou Central Hospital from January 2024 to October 2025 were enrolled. They were randomly divided into observation group (HCO group) and control group using the envelope method. T lymphocyte subsets, interleukin-6 (IL-6), procalcitonin (PCT), Acute Physiology and Chronic Health Evaluation Ⅱ (APACHE Ⅱ) score, Sequential Organ Failure Assessment (SOFA) score, 28-day mortality, and causes of death were collected before CRRT and 24 hours after treatment.  Results  A total of 80 patients were included. After 24 hours of treatment, the HCO group had higher CD3+%, CD4+%, and CD4+/CD8+ ratios compared with the control group (Z=-2.916, -2.358, -3.873, P=0.004, 0.018, ＜0.001, respectively), and lower CD8+%, IL-6, and SOFA score (Z=-3.387, -1.963, -3.345, P=0.001, 0.049, 0.001, respectively). APACHE Ⅱ score was also lower in the HCO group (t=–4.163, P＜0.001), and the reduction rate of IL‑6 was higher than that in the control group (Z=–2.858, P=0.004). No statistically significant differences were found in PCT level, PCT reduction rate (Z=–1.179, –1.010; P=0.238, 0.312), 28‑day mortality, or causes of death (P=0.522, 0.952) between the two groups.  Conclusion  HCO membrane CVVHDF helps improve organ function in septic patients by effectively removing inflammatory mediators and regulating immune homeostasis.