***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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    Input: BACKGROUND The aim of this study was to investigate the association between red blood cell ( RBC ) transfusion and haematocrit values with outcomes in infants with univentricular physiology undergoing surgery for a modified Blalock-Taussig shunt . MATERIAL AND METHODS This study included infants ≤ 2 months of age who underwent modified Blalock-Taussig shunt surgery at the Arkansas Children 's Hospital ( 2006 - 2012 ) . Infants undergoing a Norwood operation or Damus-Kaye-Stansel operation with modified Blalock-Taussig shunt were excluded . Demographics , pre-operative , operative , daily laboratory data , and post-operative variables were collected . We studied the association between haematocrit and blood transfusion with a composite clinical outcome . Multivariable logistic regression models were fitted to study the probability of study outcomes as a function of haematocrit values and RBC transfusions after operation . RESULTS Seventy-three patients qualified for inclusion . All study patients received  blood transfusion within the first 48 hours after heart surgery . The median haematocrit was 44.3 ( interquartile range [ IQR ] 42.5 - 46.2 ) , and the median volume of RBC transfused was 28 mL/kg ( IQR , 10 - 125 ) in the first 14 days after surgery . The overall in-hospital mortality rate was 13.6 % ( 10 patients ) . A multivariable analysis adjusted for risk factors , including weight , prematurity , cardiopulmonary bypass and postoperative need for nitric oxide and dialysis , revealed no association between haematocrit values and RBC transfusion with the composite clinical outcome . DISCUSSION We did not find an association between higher haematocrit values and increasing RBC transfusions with improved outcomes in infants with shunt-dependent pulmonary blood flow and univentricular physiology . The power of our study was small , which prevents any strong statement on this lack of association . Future multi-centre , r and omised controlled trials are needed to investigate this topic in further detail Objective : To determine the impact of a restrictive vs. a liberal transfusion strategy on  new or progressive multiple organ dysfunction syndrome in children post cardiac surgery . The optimal transfusion threshold after cardiac surgery in children is unknown . Design : R and omized , controlled trial . Setting : Tertiary pediatric intensive care units . Patients : Participants are a subgroup of pediatric patients post cardiac surgery from the TRIPICU ( Transfusion Requirements in Pediatric Intensive Care Units ) study . Exclusion criteria specific to the cardiac surgery subgroup included : age < 28 days and patients remaining cyanotic . Intervention : Critically ill children with a hemoglobin ≤95 g/L within 7 days of pediatric intensive care unit admission were r and omized to receive prestorage leukocyte-reduced red-cell transfusion if their hemoglobin dropped either < 70 g/L ( restrictive ) or 95 g/L ( liberal ) . Measurements and Main Results : Postoperative cardiac patients ( n = 125 ) from seven centers were enrolled . The restrictive ( n = 63 ) and liberal ( n = 62 ) groups were similar at baseline in age ( mean ± st and ard deviation = 31.4 ± 38.1 mos vs. 26.4 ± 39.1 mos ) , surgical procedure , severity of illness ( Pediatric Risk of Mortality score = 3.4 ± 3.2 vs. 3.2 ± 3.2 ) , multiple organ dysfunction syndrome ( 46 % vs. 44 % ) , mechanical ventilation ( 62 % vs. 60 % ) , and hemoglobin ( 83 vs. 80 g/L ) . Mean hemoglobin remained 21 g/L lower in the restrictive group after r and omization . No significant difference was found in new or progressive multiple organ dysfunction syndrome ( primary outcome ) in the restrictive group vs. liberal group ( 12.7 % vs. 6.5 % ; p = .36 ) , pediatric intensive care unit length of stay ( 7.0 ± 5.0 days vs. 7.4 ± 6.4 days ) or 28-day mortality ( 3.2 % vs. 3.2 % ) . Conclusion : In this subgroup analysis of cardiac surgery patients , a restrictive red-cell transfusion strategy , as compared with a liberal one , was not associated with any significant difference in new or progressive multiple organ dysfunction syndrome , but this evidence is not definitive Objective : Perioperative transfusion has adverse effects in adults undergoing cardiac surgery . We sought to investigate whether greater use of blood and blood products might be an independent predictor of prolonged postoperative recovery , indicated by duration of  mechanical ventilation ( DMV ) , after reparative infant heart surgery . Design : Secondary analysis of prospect ively collected data from two r and omized trials of hematocrit strategy during cardiopulmonary bypass in infant heart surgery to explore the association of DMV with perioperative transfusion and other variables . Setting : Tertiary pediatric hospital . Patients : Two hundred seventy infants undergoing two ventricle corrective cardiac surgery without aortic arch reconstruction . Measurements and Main Results : In univariable analyses , longer DMV was associated with younger age and lower weight at surgery , diagnostic group , and higher intraoperative and postoperative blood product transfusion ( each p < .001 ) . In multivariable proportional hazard regression , longer total support time and greater intraoperative and early postoperative blood products per kg were the strongest predictors of longer DMV . Patients in the highest tertile of intraoperative blood products per kg had an instantaneous risk of being extubated approximately half that of patients in the lowest tertile ( hazard ratio , 0.51 ; 95 % confidence interval , 0.35 , 0.73 ) . Patients who received any blood  products on postoperative day 1 , compared with those who did not , had a hazard ratio for extubation of 0.65 ( 95 % confidence interval , 0.50 , 0.85 ) . Conclusions : In this exploratory secondary analysis of infants undergoing two ventricular repair of congenital heart disease without aortic arch obstruction , greater intraoperative and early postoperative blood transfusion emerged as potential important risk factors for longer DMV . Future prospect i ve clinical trials are needed to determine whether reduction in blood product administration hastens postoperative recovery after infant heart surgery BACKGROUND  Blood transfusion in adults is associated with increased mortality and morbidity after cardiac operations . The aim of this study was to identify the main predictors of blood transfusion and explore the relationship between blood transfusion and adverse outcomes in a pediatric population . METHODS We retrospectively analyzed a prospect ively collected data base ( January 2002 to December 2003 ) of 657 consecutive pediatric patients undergoing open heart procedures in a tertiary pediatric cardiac center . Risk models were calculated for each blood product and for the total amount of blood transfused during the operation and in the first 24 hours . Postoperative adverse events were investigated after propensity score adjustment . RESULTS During the postoperative period , 30 patients ( 4.6 % ) died , 80 ( 12.2 % ) sustained nonvascular pulmonary complications , and 113 ( 17.2 % ) had infection . The risk model for the total amount of blood transfusion included weight , preoperative creatinine clearance , preoperative mechanical ventilation , duration of operation and cross-clamp , surgeon , delayed chest closure , inotropic dose , and nitric oxide administration . Univariate analyses demonstrated significant associations between blood transfusion and occurrence of every complication except of neurologic events . After adjustment for propensity score and disease severity , the total amount of blood transfusion was independently associated with an increased risk for infections ( odds ratio , 1.01 ; 95 % confidence interval , 1.002 to 1.02 ; p = 0.01 ) . Transfusion of platelets was associated with lower incidence of nonvascular pulmonary complications ( odds ratio , 0.89 ; 95 % confidence interval , 0.79 to 0.99 ; p = 0.049 ) . CONCLUSIONS The amount of blood transfusion is independently associated with infections but not with mortality The importance and variability of pre‐operative anaemia in cardiac surgical patients across the UK is not known , and there is debate about its association with patient outcomes . The Association of Cardiothoracic Anaesthetists carried out its first national audit on anaemia and transfusion , and analysed data from 19,033 patients operated on in 12 cardiac surgical centres between 2010 and 2012 ; 5895 ( 31 % ) had pre‐operative anaemia . Centre‐specific prevalence of anaemia varied from 23 % to 45 % ; anaemia was associated with older patients , diabetes and surgical risk ( EuroSCORE ) . Nevertheless , controlling for these factors , regional variation remained an independent effect ( p < 0.001 ) . Multivariable analysis demonstrated an independent association of anaemia with transfusion ( odds ratio ( 95 % confidence interval ) 2.75 ( 2.55–2.95 ) , p < 0.001 ) , mortality ( 1.42 ( 1.18–1.71 ) , p < 0.001 ) and hospital stay ( geometric mean ratio ( 95 % confidence interval ) 1.15 ( 1.13–1.17 ) , p < 0.001 ) . Haemoglobin concentration per se was also independently associated with worse outcomes ; a 10 g.l−1 decrease in haemoglobin was associated with a 43 % increase ( 95 % confidence interval 40–46 % ) in the odds of transfusion and a 16 % increase ( 95 % confidence interval 10–22 % ) in the odds of mortality ( both p < 0.001 ) . This large UK‐wide audit has demonstrated marked regional variation in both anaemia and transfusion , with a consistently high incidence of both . The independent association between pre‐operative anaemia and worse outcomes in UK practice has also been confirmed , and robust prospect i ve study of anaemia treatment before cardiac surgery is required ; these data will assist in design ing such trials BACKGROUND Red blood cell ( RBC ) transfusions are common in the pediatric intensive care unit ( PICU ) . However , there are no recent data on transfusion practice s in the PICU . Our objective was to determine transfusion practice in the PICU , to compare this practice with that observed 10 years earlier , and to estimate the compliance to the recommendation of a large r and omized clinical trial , the Transfusion Requirements in Pediatric Intensive Care Unit ( TRIPICU ) study . STUDY DESIGN AND METHODS This was a single-center prospect i ve observational study over a 1-year period . Information was abstract ed from medical charts . Determinants of transfusion were search ed for daily until the first transfusion in transfused cases or until PICU discharge in nontransfused cases . The justifications for transfusions were assessed using a question naire . RESULTS Of 913 consecutive admissions , 842 were included . At least one  RBC transfusion  was given in 144 patients ( 17.1 % ) . The mean hemoglobin ( Hb ) level before the first transfusion was 77.3 ± 27.2 g/L. The determinants of a first transfusion event retained in the multivariate analysis were young age ( < 12 months ) , congenital cardiopathy , lowest Hb level of not more than 70 g/L , severity of illness , and some organ dysfunctions . The three most frequently quoted justifications for RBC transfusion were a low Hb level , intent to improve oxygen delivery , and hemodynamic instability . The main recommendation of the TRIPICU study was applied in 96.4 % of the first transfusion events . CONCLUSIONS RBC transfusions are frequent in the PICU . Young age , congenital heart disease , low Hb level , severity of illness , and some organ dysfunctions are significant determinants of RBC transfusions in the PICU . Most first transfusion events were prescribed according to recent recommendations Objective : To examine the impact of a restrictive vs. liberal transfusion strategy on arterial lactate and oxygen content differences in children with single-ventricle physiology post cavopulmonary connection . Children with single-ventricle physiology are routinely transfused postoperatively to increase systemic oxygen delivery , and transfusion thresholds in this population have not been studied . Design : Prospect i ve , r and omized , controlled , clinical trial . Setting : Pediatric cardiac intensive care unit in a teaching hospital . Patients : Infants and children ( n = 60 ) with variations of single-ventricle physiology presenting for cavopulmonary connection . Interventions : Subjects were r and omized to a restrictive ( hemoglobin of < 9.0 g/dL ) , or liberal ( hemoglobin of ≥13.0 g/dL ) transfusion strategy for 48 hrs post operation . Primary outcome measures were mean and peak arterial lactate . Secondary end points were arteriovenous ( C(a-v)o2 ) and arteriocerebral oxygen content ( C(a-c)o2 ) differences and clinical outcomes . Measurements and Main Results : A total of 30 children were in each group . There were no significant preoperative differences . Mean hemoglobin in the restrictive and liberal groups were 11 ± 1.3 g/dL and 13.9 ± 0.5 g/dL , respectively ( 
    Output:
    
Conclusion : Evidence from RCTs in pediatric cardiac surgery , though limited , showed non-inferiority of restrictive thresholds over liberal thresholds in length of ICU stay and other outcomes following red blood cell transfusion .