***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Objectives : Pantoprazole is frequently administered to critically ill patients for prophylaxis against gastrointestinal bleeding . However , comparison to placebo has been inadequately evaluated , and pantoprazole has the potential to cause harm . Our objective was to evaluate benefit or harm associated with pantoprazole administration . Design : Prospect i ve r and omized double-blind parallel-group study . Setting : University-affiliated mixed medical-surgical ICU . Patients : Mechanically ventilated critically ill patients suitable for enteral nutrition . Interventions : We r and omly assigned patients to receive either daily IV placebo or pantoprazole . Measurements and Main Results : Major outcomes were clinical ly significant gastrointestinal bleeding , infective ventilator-associated complication or pneumonia , and Clostridium difficile infection ; minor outcomes included overt bleeding , hemoglobin concentration profiles , and mortality . None of the 214 patients r and omized had an episode of clinical ly significant gastrointestinal bleeding  , three patients met the criteria for either an infective ventilator-associated complication or pneumonia ( placebo : 1 vs pantoprazole : 2 ) , and one patient was diagnosed with Clostridium difficile infection ( 0 vs 1 ) . Administration of pantoprazole was not associated with any difference in rates of overt bleeding ( 6 vs 3 ; p = 0.50 ) or daily hemoglobin concentrations when adjusted for transfusion rates of packed red cells ( p = 0.66 ) . Mortality was similar between groups ( log-rank p = 0.33 : adjusted hazard ratio for pantoprazole : 1.68 [ 95 % CI , 0.97–2.90 ] ; p = 0.06 ) . Conclusions : We found no evidence of benefit or harm with the prophylactic administration of pantoprazole to mechanically ventilated critically ill patients anticipated to receive enteral nutrition . The practice of routine administration of acid-suppressive drugs to critically ill patients for stress ulcer prophylaxis warrants further evaluation Sixty-two mechanically ventilated patients were r and omized into three study groups to compare the efficacy of sucralfate vs cimetidine and antacid regimens for the prevention of upper gastrointestinal tract bleeding . Only five study patients ( 8 % ) developed bright-red blood per nasogastric tube ; four patients received the antacid regimen and one received cimetidine . None of the patients receiving sucralfate developed acute upper gastrointestinal tract bleeding . Bleeding was not severe enough in any patient to require endoscopy or surgery . There were no significant differences in the three groups when several major risk factors for gastrointestinal tract bleeding were analyzed , including sepsis , hypotension , steroid use , adult respiratory distress syndrome , gastric pH of 4 or less , previous peptic ulcer disease , peritonitis , and jaundice . A significantly higher incidence of acute renal failure was noted in the antacid-treated group when compared with the cimetidine and sucralfate groups . We find preliminary evidence that sucralfate is as efficacious as and more cost-effective than either cimetidine or antacids for prophylaxis of stress-related gastrointestinal tract bleeding in the critically ill ventilator-dependent patient BACKGROUND This study aim ed to assess intermittent intravenous ( IV ) pantoprazole for control of gastric acid and the possible prevention of  upper gastrointestinal ( UGI ) bleeding in intensive care units ( ICU ) patients . METHODS This was a multicenter , r and omized , open-label , dose-ranging pilot study of IV pantoprazole ( 40 mg q24 hour ; 40 mg q12 hour ; 80 mg q24 hour ; 80 mg q12 hour ; 80 mg q8 hour ) or continuously infused cimetidine ( 300 mg bolus ; 50 mg/h ) in patients at risk for UGI bleeding . The primary endpoint was percent time gastric pH > /=4.0 . UGI bleeding and pneumonia were measured as secondary endpoints . RESULTS Two hundred two ICU patients were r and omized .  Gastric pH was well controlled by all treatments . Gastric pH control improved from day 1 to day 2 in all pantoprazole groups , whereas there was decreased pH control in the cimetidine group . There were no cases of protocol defined UGI bleeding in any treatment group . Adverse event frequency and pneumonia incidence were similar between pantoprazole and cimetidine treated patients . CONCLUSIONS This pilot study indicates that intermittent IV pantoprazole effectively controls gastric pH and may protect against  UGI bleeding in high risk ICU patients without the development of tolerance A double-blind controlled trial was conducted in which the efficacy of cimetidine in a dosage of 20 mg/kg/24 h in preventing upper gastrointestinal hemorrhage was tested in 34 critically ill patients on assisted ventilation . In 28 patients , 14 on cimetidine and 14 on placebo , gastric pH measurements and blood loss measured by 51Cr-labelled erythrocytes could be analyzed . Although cimetidine produced a markedly lower number of days with a gastric pH below 3.5 ( 17.4 % vs. 72.2 % ) 5 patients on cimetidine  bled as against 1 on placebo . These results do not suggest that cimetidine was effective in preventing stress-induced upper gastrointestinal bleeding CONTEXT The use of acid-suppressive medication has been steadily increasing , particularly in the inpatient setting , despite lack of an accepted indication in the majority of these patients . OBJECTIVE To examine the association between acid-suppressive medication and  hospital-acquired pneumonia . DESIGN , SETTING , AND PATIENTS Prospect i ve pharmacoepidemiologic cohort study . All patients who were admitted to a large , urban , academic medical center in Boston , Massachusetts , from January 2004 through December 2007 ; at least 18 years of age ; and hospitalized for 3 or more days were eligible for inclusion . Admissions with time spent in the intensive care unit were excluded . Acid-suppressive medication use was defined as any order for a proton-pump inhibitor or histamine(2 ) receptor antagonist . Traditional and propensity-matched multivariable logistic regression were used to control for confounders . MAIN OUTCOME MEASURE Incidence of hospital-acquired pneumonia , defined via codes from the International Classification of Diseases , Ninth Revision , Clinical Modification ( ICD-9-CM ) , in patients exposed and unexposed to acid-suppressive medication . RESULTS The final cohort comprised 63 878 admissions .  Acid-suppressive medication was ordered in 52 % of admissions and hospital-acquired pneumonia occurred in 2219 admissions ( 3.5 % ) . The unadjusted incidence of hospital-acquired pneumonia was higher in the group exposed to acid-suppressive medication than in the unexposed group ( 4.9 % vs 2.0 % ; odds ratio [ OR ] , 2.6 ; 95 % confidence interval [ CI ] , 2.3 - 2.8 ) . Using multivariable logistic regression , the adjusted OR of hospital-acquired pneumonia in the group exposed to acid-suppressive medication was 1.3 ( 95 % CI , 1.1 - 1.4 ) . The matched propensity-score analyses yielded identical results . The association was significant for proton-pump inhibitors ( OR , 1.3 ; 95 % CI , 1.1 - 1.4 ) but not for histamine(2 ) receptor antagonists ( OR , 1.2 ; 95 % CI , 0.98 - 1.4 ) . CONCLUSIONS In this large , hospital-based pharmacoepidemiologic cohort , acid-suppressive medication use was associated with 30 % increased odds of hospital-acquired pneumonia . In subset analyses , statistically significant risk was demonstrated only for proton-pump inhibitor use Background Acid suppressive medications are used to prevent stress ulcers in critically ill patients . Few studies have been done to evaluate the effect of ranitidine and pantoprazole on stress ulcers . We aim ed to compare the effects of ranitidine and pantoprazole on Ventilator Associated Pneumonia ( VAP ) . Material s and Methods In this double-blind r and omized controlled trial , we enrolled 120 traumatic patients with trauma admitted to the intensive care unit ( ICU ) of Besat Hospital in Hamadan Province located in northwest Iran . The patients were divided into two equal groups receiving either intermittent intravenous ranitidine or pantoprazole to prevent stress ulcers . The incidence of VAP , duration of tracheal intubation , length of ICU stay , duration of hospital stay , and the outcome of treatment including mortality or hospital discharge were compared in both groups . Results The incidence of VAP was 10 % and 30 % in patients receiving ranitidine and pantoprazole , respectively ( P=0.006 ) . There was no significant difference between the two groups with respect to the duration of tracheal intubation . However , the patients treated with pantoprazole stayed at the hospital two days longer than the other patients ( P=0.027 ) . Although patients with VAP stayed at the hospital for 12 more days , the two groups had almost equal mortality rates ( P=0.572 ) . Conclusion ICU patients using pump inhibitors have a three-fold increased risk of developing VAP in comparison to H2-blocker receivers . Thus , prevention of stress ulcers should be limited to its own specific indications BACKGROUND Critically ill patients who require mechanical ventilation are at increased risk for gastrointestinal bleeding from stress ulcers . There are conflicting data on the effect of histamine H2-receptor antagonists and the cytoprotective agent sucralfate on rates of gastrointestinal bleeding , ventilator-associated pneumonia , and mortality . METHODS In a multicenter , r and omized , blinded , placebo-controlled trial , we compared sucralfate with the H2-receptor antagonist ranitidine for the prevention of upper gastrointestinal bleeding in 1200 patients who required mechanical ventilation . Patients received either nasogastric sucralfate suspension ( 1 g every six hours ) and an intravenous placebo or intravenous ranitidine ( 50 mg every eight hours ) and a nasogastric placebo . RESULTS The patients in the two groups had similar base-line characteristics . Clinical ly important gastrointestinal bleeding developed in 10 of 596 ( 1.7 percent ) of the patients receiving ranitidine , as compared with 23 of 604 ( 3.8 percent ) of those receiving sucralfate ( relative risk , 0.44 ; 95 percent confidence interval , 0.21 to 0.92 ; P=0.02 ) . In the ranitidine group , 114 of 596 patients ( 19.1 percent ) had ventilator-associated pneumonia , as compared with 98 of 604 ( 16.2 percent ) in the sucralfate group ( relative risk , 1.18 ; 95 percent confidence interval , 0.92 to 1.51 ; P=0.19 ) . There was no significant difference between the groups in mortality in the intensive care unit ( ICU ) ( 23.5 percent in the ranitidine group and 22.9 percent in the sucralfate group ) or the duration of the stay in the ICU ( median , nine days in both groups ) . CONCLUSIONS Among critically ill patients requiring mechanical ventilation , those receiving ranitidine had a significantly lower rate of clinical ly important gastrointestinal bleeding than those treated with sucralfate . There were no significant differences in the rates of ventilator-associated pneumonia , the duration of the stay in the ICU , or mortality Mixed treatment comparison ( MTC ) meta- analysis is a generalization of st and ard pairwise meta- analysis for A vs B trials , to data structures that include , for example , A vs B , B vs C , and A vs C trials . There are two roles for MTC : one is to strengthen inference concerning the relative efficacy of two treatments , by including both ' direct ' and ' indirect ' comparisons . The other is to facilitate simultaneous inference regarding all treatments , in order for example to select the best treatment . In this paper , we present a range of Bayesian hierarchical models using the Markov chain Monte Carlo software WinBUGS . These are multivariate r and om effects models that allow for variation in true treatment effects across trials . We consider models where the between-trials variance is homogeneous across treatment comparisons as well as heterogeneous variance models . We also compare models with fixed ( unconstrained ) baseline study effects with models with r and om baselines drawn from a common distribution . These models are applied to an illustrative data set and posterior parameter distributions are compared . We discuss model critique and model selection , illustrating the role of Bayesian deviance analysis , and node-based model criticism . The assumptions underlying the MTC models and their parameterization are also discussed Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more Thirty-two long-term ventilated patients were r and omly selected for a study of the efficacy of sucralfate ( 1 g six times per day via gastric tube ) versus ranitidine ( six 50-mg to six 100-mg doses per day intravenously ) for the prevention of upper gastrointestinal bleeding .  The patients of the two treatment groups ( each 16 ) 
    Output:
    
There were no convincing differences among H2RA , sucralfate , and placebo .
Mortality is probably similar across interventions ( moderate quality ) .
Conclusions Our results provide moderate quality evidence that PPIs are the most effective agents in preventing CIB , but they may increase the risk of pneumonia .