Objective：Acute respiratory distress syndrome （ARDS） is a devastating clinical syndrome whose diagnosis and therapy are still in question.The aim of this review was to discuss the current challenge for the diagnosis and treatment of ARDS.Data Sources：Data sources were the published articles in English through December 2017 in PubMed using the following key words：＂acute respiratory distress syndrome,＂ ＂definition＂,＂diagnosis,＂ ＂therapy,＂ ＂lung protective strategy,＂ ＂right ventricular dysfunction,＂ and ＂molecular mechanism.＂Study Selection：The selection of studies focused on both preclinical studies and clinical studies of therapy of ARDS.Results：The incidence of ARDS is still high,and ARDS causes high intensive care units admissions and high mortality.The Berlin Definition proposed in 2012 is still controversial owing to lack of sensitivity and specificity.ARDS is still under recognition and it is associated with high mortality.Lung protective strategies with low tidal volume （VT） and lung recruitment should consider the physiology of ARDS because ARDS presents lung inhomogeneity;the same low VT might increase local stress and strain in some patients with low compliance,and lung recruitment could injure lungs in ARDS patients with low recruitability and hemodynamic instability.Acute cor pulmonale is common in severe ARDS.ARDS itself and some treatments could worsen acute cor pulmonale.Molecular understanding of the pathogenic contributors to ARDS has improved,but the molecular-associated treatments are still under development.Conclusions：ARDS is a devastating clinical syndrome whose incidence and mortality has remained high over the past 50 years.Its definition and treatments are still confronted with challenges,and early recognition and intervention are crucial for improving the outcomes of ARDS.More clinical studies are needed to improve early diagnosis and appropriate therapy.
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
