Abstract: Objective  To systematically evaluate the efficacy of Highflow  nasal cannula oxygen therapy(HFNC)  in adult  patients with  severe  immunosuppression.Methods  Databases including PubMed, Embase, Cochrane Library, Ovid, EBSCO, WanFang, VIP, CNKI, CBM were searched by computer to collect the RCT studies about the efficacy of HFNC in adult  patients with severe immunosuppression.The retrieval time limit was from the establishment of the database to May 2019.  In order to avoid omission, the  references  included  in  the literature were  searched  manually. Revman 5.3 software was used for metaanalysis.Results  A total of 8 studies involving  1 302  patients were included. Metaanalysis  results showed that HFNC could reduce the intubation rate of patients compared with  conventional oxygen therapy (OR=0.77,  95%CI ［0.60, 0.97］,  Z=2.19,  P=0.03), but there was no statistical difference in reducing intubation rate  compared with noninvasive ventilation (OR=0.43,  95%CI［0.17,  1.08］,  Z=1.80,  P=0.07). The results of two subcombinations showed that the intubation rate of severe immunosuppressive patients  was  significantly  reduced  by  HFNC  compared with control oxygen therapy (combination:OR=0.74,  95%CI［0.58,  0.93］,  Z=2.58,  P=0.01),  but there was no significant difference in reducing mortality,  infection rate and shortening ICU  hospitalization time (case fatality rate: OR=0.84,  95%CI［0.66,  1.08］,  Z=1.34,  P=0.18,  infection rate: OR=0.80,  95%CI［0.56,  1.15］,  Z=1.19,  P=0.24,  ICU hospitalization time: OR=0.19,  95%CI［-2.51,  2.12］,  Z=0.16,  P=0.87).In sensitivity analysis HFNC could significantly reduce ICU hospitalization time compared with control oxygen therapy.Conclusion  Compared with the  control oxygen therapy,  HFNC can significantly reduce the intubation rate of patients,  but it can not reduce the mortality and infection rate of patients.

Key words: severe combined immunodeficiency, respiratory insufficiency, highflow nasal oxygen therapy, metaanalysis