The Influence Of Low Tidal Volume On Prognosis Of Patients Without Acute Respiratory Distress Syndrome:A Meta-analysis

Objective:To evaluate the effects of tidal volume on survival in adult without acute respiratory distress syndrome(non-ARDS).Methods:Electronic databases including Embase,PubMed,Cochrane,Web of Science,Chinese Biological Medical Literature,Wanfang,and CNKI were searched.Search terms included protective ventilation,protective mechanical ventilation,and low tidal and lower tidal volumes.We searched relevant clinical controlled trials from January 2000 to December 2015.Meta analyses the effects of tidal volume on mortality in non-ARDS adults were conducted using the methods recommended by the Cochrane Collaboration.Results:Nineteen randomized controlled trials(n=1679)were included.There are 841 patients ventilated with normal tidal volume and the other 838 patients ventilated with low tidal volumes.There is no difference between in control group and low tidal volume group in mortality(6.5%vs.5.8%,RR=0.9,P=0.58).There is also no difference between in control group and low tidal volume group in hospital stay and ICU stay(P=0.46&P=0.81).But respiratory complications such as development of ARDS significantly decreased in low tidal volume group[RR=0.32(95%CI,0.16-0.63),P=0.001],pneumonia decreased in lower tidal volume group[RR=0.48(95%CI,0.29-0.78),P=0.003],but there is no difference on atelectasis between two groups[RR=0.75(0.41-1.38),P=0.36].We also use sequential analysis of experiments to analysis the date and find that the cumulative Z value of small tidal volume lung protective ventilation rate,pulmonary atelectasis rate,pneumonia rate does not reach the traditional dividing value of mortality(i.e.traditional P=0.05)and the dividing value of TSA,which means there is no difference between low tidal volume group and control group before the value reaches the desired amount of information(RIS).And for the incidence of ARDS,the amount of information that TSA accumulation has reached RIS,and the Z-curve has crossed the value intersection,which means that low tidal volume ventilation in non ARDS patients reduce the incidence rate of ARDS.Conclusions:For non-ARDS patients ventilated with low tidal volumes is associated with a lower risk of development of pulmonary complications such as lung injury,pneumonia,but no benefits on mortality and atelectasis.