Purpose:To study the effect of early restrictive fluid resuscitation (EFR) on inflammatory and immune factors in patients with severe pelvic fracture (SPF).Methods:A total of 174 SPF patients in the Department of Orthopaedics,the First Affiliated Hospital of Chengdu Medical College from July 2015 to June 2018 were involved in this study and divided into EFR group (n =87) and control group (n =87) using the random number table method.Conventional fluid resuscitation (CFR) was performed in control group,and EFR was performed in EFR group.The incidences of acute respiratory distress syndrome (ARDS) and multiple organ dysfunction syndrome (MODS) during rescue,successful rescue rate,blood transfusion volume,fluid input,and resuscitation time were compared between the two groups.The parameters including prothrombin time (PT),hematocrit (HCT),platelet (PLT) and blood lactate (BL) at the 4th hour after fluid resuscitation were recorded.The levels of inflammatory factors (TNF-α,IL-6,CRP) and immune factors (CD3+,CD4+,CD8+,CD4+/CD8+) were compared between the two groups before treatment and 7 days after treatment.The revised acute physiologic and chronic health evaluation system and the sequential organ failure assessment scores were adopted for evaluation before treatment and 7 days after treatment.Results:The incidences of ARDS and MODS during rescue in EFR group were significantly lower than those in control group (p=0.015 and 0.010 respectively),and the successful rescue rate in EFR group was significantly higher than that in control group (p =0.011).The blood transfusion volume,fluid input,resuscitation time in EFR group were significantly lower than those in control group (p =0.016,0.002 and 0.001 respectively).At the 4th hour after fluid resuscitation,PTand BL in EFR group were significantly lower than those in control group (p =0.021 and 0.003 respectively),while HCT and PLT in EFR group were significantly higher than those in control group (p =0.016 and 0.021 respectively).On day 7 after treatment,TNF-α,IL-6,CRP and CD8+ in EFR group were significantly lower than those in control group (p =0.003,0.004,0.007 and 0.003 respectively),while CD3+,CD4+ and CD4+/CD8+ in EFR group were significantly higher than those in control group (p =0.004,0.000,0.007 respectively).On day 7 after treatment,the revised acute physiologic and chronic health evaluation (APACHE) system and the sequential organ failure assessment (SOFA) scores in EFR group were significantly lower than those in control group.Conclusion:EFR can effectively eliminate inflammatory factors,improve immune function,maintain the stability of blood components,reduce the incidences of ARDS and MODS,and elevate the successful rescue rate in patients with SPF.