***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 
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    ***EXAMPLES*** 
    Input: Sixty children aged 6 wk to 10 yr were studied . The children were undergoing cardiopulmonary bypass ( CPB ) for correction of congenital heart defects . The aim of the study was to provide prophylaxis for stress-induced gastric ulceration by elevating the gastric pH to at least 3.5 . Two infusion regimes of ranitidine were compared : 0.1 and 0.2 mg/kg.h . The period of study was from induction of anesthesia until the end of the first 24 h after surgery . Both regimes were effective . The 0.2-mg/kg.h infusion produced a significantly higher plasma concentration of ranitidine throughout the study period without any additional clinical benefit . Both regimes produced , within 3 h of cessation of CPB , a significant elevation in mean gastric pH to at least 5.3 . This paper concludes that 0.1-mg/kg.h infusion of ranitidine is a safe and efficacious regime for the critically ill pediatric patient Objective : To identify the incidence and factors related to  upper gastrointestinal ( UGI ) bleeding in children requiring mechanical ventilation for longer than 48 hrs . Design : Prospect i ve analytic study . Setting : Ten-bed-pediatric intensive care unit of a tertiary care University Hospital . Patients : A total of 110 patients requiring mechanical ventilation for longer than 48 hrs from January 1 , 2005 to December 31 , 2005 . Measurements and Results : UGI bleeding was defined by evidence of blood in nasogastric aspirates , hematemesis , or melena within 5 days of pediatric intensive care unit admission . We prospect ively collected data on patient demographics , admission diagnosis , operative status , and pediatric risk of mortality score . UGI bleeding and the potential risk factors including organ failure , coagulopathy , maximum ventilator setting , enteral feeding , stress ulcer prophylaxis as well as sedation were daily monitored . Of the 110 patients who required mechanical ventilation for > 48 hrs , the incidence of UGI bleeding was 51.8 % , in which 3.6 % of the cases presented with clinical ly significant bleeding ( shock , requiring blood transfusion and /or surgery ) . Significant risk factors were thrombocytopenia , prolonged partial thromboplastin time , organ failure , high pressure ventilator setting ≥25 cm H2O , and pediatric risk of mortality score ≥ 10 using univariate analysis . However , the independent factors of UGI bleeding in the multivariate analysis were organ failure ( relative risk = 2.85 , 95 % confidence interval 1.18–6.92 ) and high pressure ventilator setting ≥25 cm H2O ( relative risk = 3.73 , 95 % confidence interval 1.59–8.72 ) . Conclusion : The incidence of UGI bleeding is high in children requiring mechanical ventilation . Organ failure and high pressure ventilator setting are significant risk factors for UGI bleeding Objective To estimate the mortality and length of stay in the intensive care unit ( ICU ) attributable to clinical ly important gastrointestinal bleeding in mechanically ventilated critically ill patients . Design Three strategies were used to estimate the mortality attributable to bleeding in two multicentre data bases . The first method matched  patients who bled with those who did not  (  matched cohort ) , using duration of ICU stay prior to the bleed , each of six domains of the Multiple Organ Dysfunction Score ( MODS ) measured 3 days prior to the bleed , APACHE II score , age , admitting diagnosis , and duration of mechanical ventilation . The second approach employed Cox proportional hazards regression to match bleeding and non-bleeding patients ( model-based matched cohort ) . The third method , instead of matching , derived estimates based on regression modelling using the entire population ( regression method ) . Three parallel analyses were conducted for the length of ICU stay attributable to clinical ly important bleeding . Setting Sixteen Canadian university-affiliated ICUs . Patients A total of 1666 critically ill patients receiving mechanical ventilation for at least 48 hours . Measurements We prospect ively collected data on patient demographics , APACHE II score , admitting diagnosis , daily MODS , clinical ly important bleeding , length of ICU stay , and mortality . Independent adjudicators determined the occurrence of clinical ly important gastrointestinal bleeding , defined as overt bleeding in association with haemodynamic compromise or blood transfusion . Results Of 1666 patients , 59 developed clinical ly important gastrointestinal bleeding . The mean APACHE II score was 22.9 ± 8.6 among bleeding patients and 23.3 ± 7.7 among non-bleeding patients . The risk of death was increased in patients with bleeding using all three analytic approaches ( matched cohort method : relative risk [RR]= 2.9 , 95 % confidence interval (CI)= 1.6–5.5 ; model-based matched cohort method : RR = 1.8 , 95 % CI = 1.1–2.9 ; and the regression method : RR = 4.1 , 95 % CI = 2.6–6.5 ) . However , this was not significant for the adjusted regression method ( RR = 1.0 , 95 % CI = 0.6–1.7 ) . The median length of ICU stay attributable to clinical ly important bleeding for these three methods , respectively , was 3.8 days ( 95 % CI = -0.01 to 7.6 days ) , 6.7 days ( 95 % CI = 2.7–10.7 days ) , and 7.9 days ( 95 % CI = 1.4–14.4 days ) . Conclusions Clinical ly important upper gastrointestinal bleeding has an important attributable morbidity and mortality , associated with a RR of death of 1–4 and an excess length of ICU stay of approximately 4–8 days Background No surveys of  stress ulcer prophylaxis prescribing in the USA havebeen conducted since 1995 . Since that time , the most comprehensive meta- analysis and largest r and omized study to date concerning stress ulcer prophylaxis havebeen published . Results Three hundred sixty-eight surveys were sent to all members of theSection of Pharmacy and Pharmacology of the Society of Critical Care Medicine . One hundred fifty-three ( 42 % ) surveys were returned . Representatives from 86%of institutions stated that medications for stress ulcer prophylaxis are usedin a majority ( > 90 % ) of patients admitted to the intensive care unit (ICU).Twenty-two per cent of institutions have recommendations for both ICU and non-ICU setting s. Fifty-eight per cent of institutions stated that there wasone preferred medication for stress ulcer prophylaxis , and in 77 % of thesehistamine-2-antagonists were the most popular . Conclusions There are wide variations in prescribing practice s for stressulcer prophylaxis . Institutions should consult published literature and usepre-existing guidelines as templates for developing their own guidelines We determined the ranitidine dosage necessary to maintain gastric pH at or above 4 in 40 critically ill children . The patients were divided into four groups of ten patients each . They were treated with ranitidine in the following dosages : a ) 2 mg/kg by NG tube every 12 h ; b ) 4 mg/kg by NG tube every 12 h ; c ) 0.75 mg/kg iv every 6 h ; d ) 1.5 mg/kg iv every 6 h. The fourth group had a higher median pH than the other groups , in spite of also having the highest risk of acute gastric mucosal damage ( AGMD ) . Eight ( 80 % ) of ten patients in the fourth group had a pH greater than or equal to 4 or more than 80 % of the study period . We recommend 1.5 mg/kg iv every 6 h for gastric acid inhibition in AGMD prophylaxis in children OBJECTIVE To determine whether the dose of ranitidine recommended in commonly used pediatric drug dosage h and books ( 2 to 4 mg/kg/day i.v . ) results in successful gastric pH control ( pH of > 4 ) in critically ill children . DESIGN Prospect i ve sample . SETTING Pediatric intensive care unit in a tertiary care children 's hospital . PATIENTS Fifty consecutive patients who received > 24 hrs of scheduled intermittent intravenous ranitidine for stress ulcer prophylaxis were enrolled in the study . Patients with renal or hepatic dysfunction and those who received enteral nutrition through the nasogastric tube were excluded from enrollment . INTERVENTION Gastric pH was determined at the end of the ranitidine dosing interval , 1 hr after the dose , and at the midpoint between doses . All pH measurements were made from a sample of nasogastric aspirate , using pH sensitive paper . Gastric pH control with ranitidine was considered unsuccessful ( poorly controlled ) if the pH was < 4 for any of the three measurements . MEASUREMENTS AND MAIN RESULTS Forty-five patients ( median age 36 mos ; range 2 wks to 264 mos ) were included in the analysis . Eighty-two percent of the patients were mechanically ventilated , 16 % were pharmacologically paralyzed , 18 % required vasoactive infusions , 36 % were nourished via transpyloric feeding tubes , and 7 % received total parenteral nutrition . Gastric pH was poorly controlled in 36 % of patients . Among these patients , the pH at the end of the dosing interval was significantly lower than the pH measured at 1 hr or at the midpoint between doses ( p < .05 ) . Seventy-one percent of patients who received <3 mg/kg/day of ranitidine had poor gastric pH control as compared with 19 % who received a minimum of 3 mg/kg/day ( p < .05 ) . Poor control of gastric pH was not associated with feeding , intubation status , presence of pharmacologic paralysis , use of vasoactive infusions , or age ( p > .05 ) . CONCLUSIONS The minimum ranitidine dose recommended in commonly used pediatric drug references result ed in unsuccessful gastric pH control in a high percentage of pediatric intensive care unit patients . Critically ill children with normal renal and hepatic function should be treated with a minimum 3 mg/kg/day of intravenous ranitidine and the dose should be titrated to a gastric pH of > or = 4 Objectives . To determine the incidence , risk factors , and complications associated with or attributable to clinical ly significant upper gastrointestinal ( GI ) bleeding acquired in a pediatric intensive care unit ( ICU ) . Methods . Prospect i ve , descriptive epidemiologic study in a multidisciplinary pediatric ICU of a tertiary-care university hospital . Upper GI bleeding was considered to be present if hematemesis occurred or blood was present in the gastric tube . An upper GI bleed was qualified as clinical ly significant if two or three review ers independently assessed that at least one of the six complications considered for analysis was attributable to the upper GI bleed . Results . A cohort of 1114 consecutive admissions was enrolled ; 108 ( 9.7 % ) were excluded mostly ( 37.0 % ) because they already had an upper GI bleed at entry to the pediatric ICU . The final sample included 1006 admissions ( 881 patients ) ; 103 upper GI bleeds ( 10.2 % ) were diagnosed , including 16 clinical ly significant upper GI bleeds ( 1.6 % ) . Complications attributed to an upper GI bleed included : decreased hemoglobin concentration ( 10 cases ) , transfusion ( 10 ) , hypotension ( 3 ) , and surgery ( 1 ) . Three independent risk factors for clinical ly significant upper GI bleeding were retained by multivariate analysis : respiratory failure , coagulopathy , and pediatric risk of mortality score ≥10 . Nine of the 16 cases ( 56.3 % ) with clinical ly significant upper GI bleeding had three risk factors , 14 ( 87.5 % ) had two , and 1 ( 6.3 % ) had none . Conclusions . Clinical ly significant upper GI bleeds are rare in critically ill children . Prophylaxis to prevent them may be limited to patients who present with at least two risk factors PURPOSE The purpose of the study was to evaluate the effects of sucralfate , ranitidine , and omeprazole use on incidence of ventilatory-associated pneumonia ( VAP ) and mortality in ventilated pediatric critical care patients . MATERIAL S AND METHODS This prospect i ve study was conducted at the pediatric intensive care unit ( PICU ) between August 2000 and February 2002 . A total of 160 patients who needed mechanical ventilation were r and omized into 4 groups according to the computer-generated r and om number table : group ( S ) , ( n = 38 ) received sucralfate suspension 60 mg/kg/d in 4 doses via the nasogastric tube that was flushed with 10 mL of sterile water ; group ( R ) , ( n = 42 ) received ranitidine 2 mg/kg/d intravenously in 4 doses ; group ( O ) , ( n = 38 ) received omeprazole 1 mg/kg/d intravenously in 2 doses ; and group ( P ) , ( n = 42 ) did not receive any medication for stress ulcer prophylaxis . Treatment was begun within 6 hours of PICU admission . RESULTS Seventy patients ( 44 % 
    Output:
    
No significant differences were found when comparing different drugs ( omeprazole , ranitidine , sucralfate , famotidine , amalgate ) , doses , or regimens for main outcomes ( deaths , endoscopic findings of erosion or ulcers , upper gastrointestinal bleeding , or pneumonia ) .