***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: The EBN users ’ guide in the previous issue of Evidence -Based Nursing outlined the primary and secondary questions for evaluating studies of healthcare interventions . One of the primary questions for assessing the validity of a study ’s findings is whether the assignment of patients to treatments was r and omised and whether r and omisation was concealed . One of the secondary questions is whether patients , clinicians , outcome assessors , and data analysts were unaware of ( blinded to or masked from ) patient allocation . Beginning with the October 1999 issue of Evidence -Based Nursing , allocation concealment and blinding have been given more attention . The “ design ” section of abstract s of r and omised trials now includes a statement of whether r and omisation was concealed from those responsible for entering patients into trials , and who was blinded to treatment allocation during the trials . These additional specifications provide readers with more information to judge the internal validity of trials . In this editorial , the background and rationale for these decisions are addressed The effect on gastric pH and volume of 0 , 6 and 10 ml · kg−1 , of apple juice given 2.5 hours before surgery to children aged five to ten years was investigated in this prospect i ve , r and omized , single-blind study . Gastric contents were aspirated after induction of anaesthesia , and the volume measured . The pH of the gastric aspirate was then assessed using pH paper . Neither gastric volume nor pH immediately following the induction of general anaesthesia were significantly different among the three groups . Gastric volumes after 0 , 6 and 10 ml · kg−1 , of juice averaged ( mean ±SD ) 0.45 ±0.31 , 0.66 ±0.79 and 0.71 ±0.76 ml · kg−1 , respectively ; gastric pH averaged 1.7 ±0.6 , 1.7 ±0.6 and 1.8 ±0.8 , respectively . On the basis of questions asked immediately before induction of anaesthiesia , patients who drank 6 ml · kg−1 of apple juice had decreased thirst and were less irritable and upset before anaesthesia than those who had not ( P < 0.05 ) . It is concluded that drinking large volumes of clear apple juice 2.5 hours before scheduled surgery does not have a measurable effect on gastric volume and pH and may offer benefits such as improved patient comfort . RésuméL’effet sur le volume et le pH gastrique de 0,6 et 10 ml · kg−1 de jus de pomme donné 2.5 heures avant la chirurgie aux enfants âgés de cinq à dix ans a été investigué dans cette étude prospect i ve r and omisée et a simple insu . Le contenu gastrique fut aspiré après induction de l’anesthésie et le volume mesuré . Le pH du sue gastrique aspiré a par la suite été évalué par un papier à pH. Ni le volume gastrique ni son pH n’était significativement différent pour les trois groupes après l’induction de l’anesthesie générale . Le volume gastrique après 0,6 et 10 ml · kg−1 de jus de pomme était en moyenne ( moyenne ±SD ) respectivement 0,45 ±0,31 , 0,66 ±0,79 et 0,71 ±0,76 ml · kg−1 , en moyenne le pH gastrique était de 1,7 ±0,6 , 1,7 ±0,6 et 1,8 ±0,8 . Pour les avoir question né immédiatement avant l’induction de l’anesthésie les patients ayant bu 6 ml · kg−1 de jus de pomme avaient moins soif et étaient moins irritables avant l’anesthésie que ceux qui n’en ont pas eu ( P < 0.05 ) . On conclut que l’ingestion dun large volume de jus de pomme 2.5 heures avant la chirurgie n’a pas d’effet mesurable sur le volume et le pH gastrique et peut offrir des bénéfices tel que l’amélioration du confort du patient Composite outcomes , in which multiple end points are combined , are frequently used as primary outcome measures in r and omized trials and are often associated with increased statistical efficiency . However , such measures may prove challenging for the interpretation of results . In this article , we examine the use of composite outcomes in major clinical trials , assess the arguments for and against them , and provide guidance on their application and reporting . To assess incidence and quality of reporting , we systematic ally review ed the use of composite end points in clinical trials in Annals of Internal Medicine , BMJ , Circulation , Clinical Infectious Diseases , Journal of the American College of Cardiology , JAMA , Lancet , New Engl and Journal of Medicine , and Stroke from 1997 through 2001 using a sensitive search strategy . We selected for review 167 original reports of r and omized trials ( with a total of 300 276 patients ) that included a composite primary outcome that incorporated all-cause mortality .  Sixty-three trials ( 38 % ) were neutral both for the primary end point and the mortality component . Sixty trials ( 36 % ) reported significant results for the primary outcome measure but not for the mortality component . Only 6 trials ( 4 % ) were significant for the mortality component but not for the primary composite outcome , whereas 19 trials ( 11 % ) were significant for both . Twenty-two trials ( 13 % ) were inadequately reported . Our review suggests that reporting of composite outcomes is generally inadequate , implying that the results apply to the individual components of the composite outcome rather than only to the overall composite . Current guidelines for the undertaking and reporting of clinical trials could be revised to reflect the common use of composite outcomes in clinical trials Eighty-eight children ( mean age 5.6 yr , range 1 - 14 yr ) about to undergo elective outpatient surgery were r and omly assigned to four groups . All children were given phenolsulfonphthalein ( PSP ) orally 2 - 3 h before the scheduled time of surgery as a marker dye to assess gastric emptying . Immediately after receiving PSP they were given : group A -- liquids , up to 5 ml/kg + placebo ( glucose water 0.2 ml/kg ) ; group B -- liquids , up to 5 ml/kg + ranitidine 2 mg/kg in glucose water 0.2 ml/kg ; group C -- placebo only ; group D -- ranitidine only . Gastric contents were aspirated after induction of anesthesia . Mean volume ( range ) in ml/kg of aspirated gastric fluid in each group was : group A--0.34 ( 0 - 1.0 ) ; group B--0.17 ( 0.07 ) ; group C--0.25 ( 0 - 1.1 ) ; group D--0.16 ( 0 - 0.6 ) . The pH mean ( range ) value was : group A--1.83 ( 0.9 - 3.6 ) ; group B--4.76 ( 2.0 - 7.7 ) ; group C--2.10 ( 1.2 - 4.1 ) ; group D--3.97 ( 1.3 - 7.3 ) .  PSP  could not be detected in the gastric sample s from children in whom the ingestion-sampling interval was more than 2.25 h. In comparison with prolonged starvation , administration of oral liquids without ranitidine 2 - 3 h preoperatively did not produce a significant increase in mean volume of gastric aspirate , and there was no increase in the number of patients with gastric aspirate greater than 0.4 ml/kg . Administration of ranitidine with or without fluids result ed in a decrease in both volume and acidity of gastric contents Blood glucose concentrations were measured in 82 children undergoing inpatient anaesthesia and in 46 children undergoing anaesthesia as out patients . The children were aged between 6 months and 9 yr . Out patients were fasted from bedtime , while in patients were r and omly allocated to two groups . In group A the children were fasted from bedtime , whereas in group B the children were fed 6 h before anaesthesia . There was no difference in mean blood glucose concentration between the fasted in patients and out patients nor between children younger than , or older than , 4 years of age . A blood glucose concentration of less than 40 mg dl-1 was found in only one of the fasted children ( 1 % ) . The mean blood glucose concentration was greater in group B than A , but only significantly so for children older than 4 yr . It is concluded that to minimize the risks of hypoglycaemia and inhalation of vomit on induction of anaesthesia children older than 6 months should be fasted overnight and operated on in the morning The effect of pre-operative intake of oral water and ranitidine on gastric fluid volume and pH was studied in 75 children of American Society of Anesthetists ( ASA ) grade I and grade II undergoing elective surgery . Group I patients fasted from midnight and acted as control . Group II patients received 5 ml/kg plain water orally 3 hours before surgery . Group III children received 5 ml/kg of plain water and 2 mg/kg of ranitidine orally 3 hours before surgery . Mean volume of gastric aspirate was comparable in all 3 groups ( p > 0.05 ) . Mean pH was significantly higher in ranitidine treated patients ( 5.12 + /- 1.73 ) as compared to non-ranitidine treated patients ( 2.26 + /- 0.57 and 2.53 + / 0.79 in group I and group II respectively ) . Number of patients at risk ( pH < or = 2.5 and volume > or = 0.4 ml/kg ) was not significantly different in group I and group II . Mean thirst and behaviour scores were significantly higher in fluid treated patients ( groups II and III ) as compared to control ( p < 0.01 ) . To conclude , administration of pre-operative water ( 5 ml/kg ) along with ranitidine ( 2 mg/kg ) favourably modifies gastric fluid volume and pH , improves patient behaviour and minimises the number of patients at risk of aspiration pneumonitis , should the child aspirate To determine the effect of rice porridge feeding before elective surgery on preoperative gastric fluid pH , volume and starvation , a prospect i ve study was undertaken in pediatric patients . Twenty healthy children ranged in age from 5 to 12 years were allocated r and omly to either a fasted or rice porridge group . The children of fasted group ( control group ) were allowed to take solid food until midnight before the operation . The rice porridge group ( study group ) patients received a small amount of rice porridge 5 hours 30 minutes before the induction of anesthesia . The patients of both groups were permitted to take clear fluid until 5 hours before the induction of anesthesia . After the induction of anesthesia , gastric fluid was aspirated through an orogastric tube . The mean gastric fluid volume was 0.43 + /- 0.32 ml.kg-1 in the control group and 0.5 + /- 0.6 ml.kg-1 in the study group . The mean gastric fluid pH was 1.43 + /- 0.27 ml.kg-1 in the control group and 1.89 + /- 0.75 ml.kg-1 in the study group . There were no significant differences between the two groups concerning the gastric fluid volume and pH. The patient of the study group complained of less hunger . Preoperative rice porridge feeding is a possible preoperative feeding for pediatric patients The effect of 3 ml·kg-1 of apple juice given 2.6 ± 0.4 hours preoperatively was investigated in 80 healthy children of ages five to ten years in this prospect i ve , r and omized , single blind study . The children who drank apple juice preoperatively had decreased gastric volume , thirst , and hunger ( p < 0.05 ) . The gastric volume in the control group was 0.43 ± 0.46 ml·kg-1 and in the patients who received apple juice the gastric volume was 0.24 ± 0.31 ml·kg-1 . The gastric pH was not significantly different , with the control group ’s gastric pH being 1.7 ± 0.6 and the treated group ’s pH was 2.2 ± 1.2 . Further studies of the effects of different volumes and timing of preoperative clear fluids are indicated in paediatric patients .RésuméNous avons entrepris une étude prospect i ve , r and omisée et à ľaveugle pour déterminer ľeffet de 3 ml · kg-1 de jus de pomme donné 2.6 ± 0.4 h. avant ľopération à 80 enfants agés de 5 à 10 ans . Les enfants qui avaient bu du jus avant ľopération avaient moins f aim et soif et leurs volumes gastriques étaient moindres ( p < 0.05 ) . Le volume gastrique était de 0.43 ± 0.46 ml · kg-1 chez le groupe contrôle , et de 0.24 ± 0.31 ml · kg-1 chez le groupe “ jus de pomm ” . Le pH du liquide se chiffrait à 1.7 ± 0.6 pour les contrôles et à 2.2 ± 1.2 pour les buveurs de jus , écart non significatif . On aura besoin ďautres études pour préciser ľimpact du volume et de ľintervalle ďadministration des liquides clairs chez les enfants The perioperative blood glucose regulatory response was compared in 20 healthy children ( aged 1 - 5 yr 
    Output:
    
Children permitted fluids up to 120 minutes preoperatively were not found to experience higher gastric volumes or lower gastric pH values than those who fasted .
The children permitted fluids were less thirsty and hungry , better behaved and more comfortable than those who fasted .
Clear fluids preoperatively did not result in a clinical ly important difference in children 's gastric volume or pH. Evidence relating to the preoperative intake of milk was sparse .
The volume of fluid permitted during the preoperative period did not appear to impact on children 's intraoperative gastric volume or pH contents .
AUTHORS ' CONCLUSIONS There is no evidence that children who are denied oral fluids for more than six hours preoperatively benefit in terms of intraoperative gastric volume and pH compared with children permitted unlimited fluids up to two hours preoperatively .
Children permitted fluids have a more comfortable preoperative experience in terms of thirst and hunger .
This evidence applies only to children who are considered to be at normal risk of aspiration/regurgitation during anaesthesia