Background:Although the use of extra-corporeal membrane oxygenation (ECMO) has been rapidly increasing,the benefit of ECMO in patients with acute respiratory distress syndrome (ARDS) remains unclear.Our objective was to investigate the effect of venovenous ECMO (VV-ECMO) on adult patients with severe ARDS.Methods:We conducted a multi-center,retrospective,cohort study in the intensive care units (ICUs) of six teaching hospitals between January 2013 and December 2018.Patients with severe ARDS who received W-ECMO support were included.The detailed demographic data and physiologic data were used to match ARDS patients without ECMO.The primary endpoint was the 28-day mortality.Results:Ninety-nine patients with severe ARDS supported by VV-ECMO and 72 patients without ECMO were included in this study.The acute physiology and chronic health evaluation Ⅱ score was 23.1 ± 6.3 in the ECMO group and 24.8 ± 8.5 in the control group (P =0.1195).The sequential organ failure assessment score was 12.8 ± 3.4 in the ECMO group and 13.7 ± 3.5 in the control group (P =0.0848).The 28-day mortality of patients with ECMO support was 39.4%,and that of the control group was 55.6%.The survival analysis curve showed that the 28-day mortality in the ECMO group was significantly lower than that in the control group (P =0.0097).Multivariate Cox regression analysis showed that the independent predictors of the 28-day mortality were the requirement of vasopressors before ECMO (hazard ratio [HR]:1.006;95% confidence interval [CI]:1.001-1.013;P =0.030) and duration of mechanical ventilation before ECMO (HR:3.299;95% CI:1.264-8.609;P =0.034).Conclusions:This study showed that ECMO improved the survival of patients with severe ARDS.The duration of mechanical ventilation and the requirement of vasopressors before ECMO might be associated with an increased risk of death.
Background High-frequency oscillatory ventilation （HFOV） allows for small tidal volumes at mean airway pressures （mPaw） above that of conventional mechanical ventilation （CMV）,but the effect of HFOV on hemodynamics,oxygen metabolism,and tissue perfusion in acute respiratory distress syndrome （ARDS） remains unclear.We investigated the effects of HFOV and CMV in sheep models with ARDS.Methods After inducing ARDS by repeated lavage,twelve adult sheep were randomly divided into a HFOV or CMV group.After stabilization,standard lung recruitments （40 cmH2O × 40 seconds） were performed.The optimal mPaw or positive end-expiratory pressure was obtained by lung recruitment and decremental positive end-expiratory pressure titration.The animals were then ventilated for 4 hours.The hemodynamics,tissue perfusion （superior mesenteric artery blood flow,pHi,and Pg-aCO2）,oxygen metabolism and respiratory mechanics were examined at baseline before saline lavage,in the ARDS model,after model stabilization,and during hourly mechanical ventilation for up to 4 hours.A two-way repeated measures analysis of variance was applied to evaluate differences between the groups.Results The titrated mPaw was higher and the tidal volumes lower in the HFOV group than the positive end-expiratory pressure in the CMV group.There was no significant difference in hemodynamic parameters between the HFOV and CMV groups.There was no difference in the mean alveolar pressure between the two groups.After lung recruitment,both groups showed an improvement in the oxygenation,oxygen delivery,and DO2.Lactate levels increased in both groups after inducing the ARDS model.Compared with the CMV group,the superior mesenteric artery blood flow and pHi were significantly higher in the HFOV group,but the Pg-aCO2 decreased in the HFOV group.Conclusion Compared with CMV,HFOV with optimal mPaw has no significant side effect on hemodynamics or oxygen metabolism,and increases gastric tissue blood perfusion.
Liu Songqiao Huang Yingzi Wang Maohua Chen Qiuhua Liu Ling Xie Jianfeng Tan Li Guo Fengmei Yang Congshan Pan Chun Yang Yi Qiu Haibo
