The Investigation And Practical Application Of Meta-analysis In Emergency And Critical Care Medicine

IntroductionEvidence-based medicine, EBM, is a new medical model which has been developing quickly and has filtered into every field of clinical medicine. In1996, Sackett firstly described EBM as"the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients". And in2000, Sackett and his colleagues updated the definition of EBM to "the combination of the best clinical evidence, individual clinical expertise and patient values&expectations". The best clinical evidence is emphasized in its definition. One of approaches which are used to obtain the best clinical evidence is systematic review and Meta-analysis, especially Meta-analysis which can provide clinical physicians with quantitative clinical evidence. Both emergency and critical care medicine needs the best clinical evidences. However, the current state of Meta-analysis and the introduction of how to practice Meta-analysis in emergency and critical care medicine are not clear enough. The objective of present study was to explore the application status of Meta-analysis in emergency and critical care medicine through searching the literatures which were published in30journals.And the present study also analyzed how to practice Meta-analysis in emergency and critical care medicine from three different points:intervention study (randomized controlled trials), observational study, and diagnostic study. Part I The current status of application of Meta-analysis in emergency and critical care medicineObjective:The objective of this study was to explore the current status and possible flaws of the application of Meta-analysis in emergency and critical care medicine and to provide reference for future studies.Methods:We systematically searched Meta-analysis which were published on30journals during2000.01.01and2013.12.31through PUBMED. And the impact factors of these journals were all more than1.0, including27emergency and critical care medicine professional journals and3comprehensive journals. The extraction of data was peformed by Epidata software and the analysis of data were performed by Microsoft Excel2010and Sigmaplot software.Results:456Meta-analysis were identified. The number of Meta-analysis published in emergency and critical care medicine generally increased from2000to2013.64Meta-analysis were published in CRIT CARE MED,57in CRIT CARE and49in INTENS CARE MED. The majority of the first authors of all included Meta-analysis were from North America (176) and Europe (140). And most of the included Meta-analysis (289) were performed in university hospital.248Meta-analysis, namely54.4%of all eligible Meta-analysis were the Meta-analysis of randomized controlled trials. The number of studies included in each Meta-analysis was most between6and10, and the median of sample size of each Meta-analysis was1292.110(24.1%) Meta-analysis focused on cardiovascular system. Mortality was the most frequently evaluated indictor (245). And the methodological quality of included Meta-analysis was above average based on the PRISMA. Conclusions:The number of Meta-analysis published in emergency and critical care medicine generally increased, and most of these Meta-analysis were came from the North America and Europe and were performed by university hospitals. The methodological quality of included Meta-analysis was above average. However, it has lots of flaw in the following sections:protocol and registration, search, study selection, data collection process and risk of bias across studies in the outcome section, and the rate of adherence to these standards all were below60%. Part Ⅱ The value of whole-body CT in major trauma patients:A meta-analysis of observational studiesObjective:The aim of this study was to assess the value of immediate whole-body computed tomography (WBCT) during the primary survey of major trauma patients.Methods:A comprehensive search for articles from PUBMED, Cochrane Library database, China biology medical literature database (CBM), Web of knowledge, ProQuest, EBSCO, OvidSP (EMBASE), and www.clinicalTrials.gov. Reports were eligible if they contained original data comparing immediate Whole-body CT with conventional imaging in major trauma patients. The main outcome of interest was the effect of WBCT on mortality rate.The secondary outcomes included:time spent in the emergency department (ED), duration of mechanical ventilation, ICU and hospital length of stay (LOS), the incidence of Multiple Organ Dysfunction Syndrome (MODS) or Multiple Organ Failure (MOF). Data were analyzed and processed using Review Manager5.2.5and Stata12.0.Results:Eleven trials enrolling26371patients were analyzed quantitatively. Firstly, patients in whole-body CT group with a lower risk of death than control group, the pooled OR was0.64;95%CI:0.50-0.82. Secondly, the application of WBCT was associated with a shorter stay in the emergency department (weighted mean difference (WMD),-27.58min;95%CI:-43.04-12.12). Unexpectedly, the application of WBCT had a tendency to extend the length of ICU stay (WMD,0.95days;95%CI:0.08-1.98) and the length of hospital stay (WMD,0.56days;95%CI:-0.03-1.15). Finally, this practice seemed to increase the incidence of Multiple Organ Dysfunction Syndrome, MODS/Multiple Organ Failure, MOF (OR,1.44;95%CI:1.35-1.54) and was associated with a longer duration of mechanical ventilation (WMD,0.96days;95%CI:0.32-1.61).Conclusions:Our meta-analysis suggests that the application of whole-body CT significantly reduced the mortality rate of major trauma patients, and markedly reducing the time spent in the emergency department. Part Ⅲ Albumin versus other fluids for fluid resuscitation in patients with sepsis:A meta-analysis of randomized controlled trialsObjective;Early fluid resuscitation is vital to patients with sepsis. However, the choice of fluid has been a hot topic of discussion. The objective of this study was to evaluate whether the early use of albumin-containing fluids for resuscitation in patients with sepsis was associated with an increased survival rate.Methods:We systematically searched PUBMED, EMBASE and Cochrane library for eligible randomized controlled trials (RCTs) up to March2014. The primary endpoint was all-cause mortality. The selection of eligible studies, assessment of methodological quality, and extraction of all relevant data were conducted by two authors independently.Results:In total,15RCTs were eligible for analysis. After pooling the data, we found there was no significant effect of albumin-containing fluids on mortality in patients with sepsis of any severity (RR:0.94,95%CI:0.87-1.02). The results were robust to subgroup analyses, sensitivity analyses and trial sequential analyses.Conclusion:The present meta-analysis did not demonstrate significant advantage of using albumin-containing fluids for resuscitation in patients with sepsis of any severity. Given the cost-effectiveness of using albumin, crystalloids should be the first choice for fluid resuscitation in septic patients. Part Ⅳ Role of transthoracic ultrasonography in the diagnosis of pulmonary embolism:A meta-analysis of diagnostic studiesObjective:The aim of this meta-analysis was to evaluate the overall diagnostic accuracy of transthoracic ultrasound (TS) in the diagnosis of acute pulmonary embolism (PE).Methods:PUBMED, Web of science, OvidSP, ProQuest, EBSCO, Cochrane Library and Clinicaltrial.gov were searched systematically. The quality of included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2tool. The sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR) and hierarchical summary receiver operating characteristic (HSROC) curves were used to examine TS performance. Publication bias was assessed with Deeks funnel plot.Results:The results indicated that the sensitivity, specificity, PLR and NLR were0.85(95%confidence interval (CI),0.78-0.90),0.83(95%CI,0.73-0.90),5.09(95%CI,3.25-7.97), and0.18(95%CI,0.12-0.25). And the DOR and HSROC were28.82(95%CI17.60-47.21) and0.91(95%CI,0.88-0.93). There was no evidence of publication bias. The pre-test probability of acute PE was divided into1.3%,16.2%and40.6%based on the Wells score, when the TS was positive, the post-test probability of acute PE would rise to6%,50%, and78%respectively; when the TS was negative, the post-test probability of acute PE would drop to0%,3%, and11%. Conclusion:TS was a useful method in diagnosing PE. Given the excessive use of computed tomography pulmonary angiography (CTPA), the application of TS with other diagnostic approaches may significantly reduce the number of unnecessary CTPA.