human
***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: BACKGROUND Optimal fluid management in patients with acute lung injury is unknown . Diuresis or fluid restriction may improve lung function but could jeopardize extrapulmonary-organ perfusion . METHODS In a r and omized study , we compared a conservative and a liberal strategy of fluid management using explicit protocol s applied for seven days in 1000 patients with acute lung injury . The primary end point was death at 60 days . Secondary end points included the number of ventilator-free days and organ-failure-free days and measures of lung physiology . RESULTS The rate of death at 60 days was 25.5 percent in the conservative- strategy group and 28.4 percent in the liberal- strategy group ( P=0.30 ; 95 percent confidence interval for the difference , -2.6 to 8.4 percent ) . The mean ( + /-SE ) cumulative fluid balance during the first seven days was -136+/-491 ml in the conservative- strategy group and 6992+/-502 ml in the liberal- strategy group ( P<0.001 ) . As compared with the liberal strategy , the conservative strategy improved the oxygenation index ( [ mean airway pressure x the ratio of the fraction of inspired oxygen to the partial pressure of arterial oxygen]x100 ) and the lung injury score and increased the number of ventilator-free days ( 14.6+/-0.5 vs. 12.1+/-0.5 , P<0.001 ) and days not spent in the intensive care unit ( 13.4+/-0.4 vs. 11.2+/-0.4 , P<0.001 ) during the first 28 days but did not increase the incidence or prevalence of shock during the study or the use of dialysis during the first 60 days ( 10 percent vs. 14 percent , P=0.06 ) . CONCLUSIONS Although there was no significant difference in the primary outcome of 60-day mortality , the conservative strategy of fluid management improved lung function and shortened the duration of mechanical ventilation and intensive care without increasing nonpulmonary-organ failures . These results support the use of a conservative strategy of fluid management in patients with acute lung injury . ( Clinical Trials.gov number , NCT00281268 [ Clinical Trials.gov ] . ) OBJECTIVE To determine whether dexamethasone prevents postextubation airway obstruction in young children . DESIGN Prospect i ve , r and omized , double-blind , placebo-controlled study . SETTING Pediatric intensive care unit of a university teaching hospital . PATIENTS Sixty-six children , < 5 yrs of age , intubated and mechanically ventilated for > 48 hrs . INTERVENTIONS Patients were r and omized to receive intravenous dexamethasone ( 0.5 mg/kg , maximum dose 10 mg ) or saline , every 6 hrs for six doses , beginning 6 to 12 hrs before elective extubation . MEASUREMENTS AND MAIN RESULTS Dependent variables included the presence of stridor , Croup Score , and pulsus paradoxus at 10 mins , 6 , 12 , and 24 hrs after extubation ; need for aerosolized racemic epinephrine and reintubation . The dexamethasone and placebo groups were similar in age ( median 3 months [ range 1 to 57 ] vs. 4 months [ range 1 to 59 ] , p = .6 ) , frequency of underlying airway anomalies ( 3/33 vs. 3/33 , p = 1.0 ) , and duration of mechanical ventilation ( median 3.3 days [ range 2.1 to 39 ] vs. 3.5 days [ range 2.1 to 15 ] , p = .7 ) . The dexamethasone group had a lower frequency of stridor , Croup Score , and pulsus paradoxus measurement at 10 mins and at 6 and 12 hrs after extubation . Fewer dexamethasone-treated patients required epinephrine aerosol ( 4/31 vs. 22/32 , p < .0001 ) and reintubation ( 0/31 vs. 7/32 , p < .01 ) . Three patients exited the study early-one patient in the dexamethasone group had occult gastrointestinal hemorrhage and one patient in each group had hypertension . CONCLUSION Pretreatment with dexamethasone decreases the frequency of postextubation airway obstruction in children A 2-h T-tube trial of spontaneous breathing was used in selecting patients ready for extubation and discontinuation of mechanical ventilation . However , some doubt remains as to whether it is the most appropriate method of performing a spontaneous breathing trial . We carried out a prospect i ve , r and omized , multicenter study involving patients who had received mechanical ventilation for more than 48 h and who were considered by their physicians to be ready for weaning according to clinical criteria and st and ard weaning parameters . Patients were r and omly assigned to undergo a 2-h trial of spontaneous breathing in one of two ways : with a T-tube system or with pressure support ventilation of 7 cm H2O . If a patient had signs of poor tolerance at any time during the trial , mechanical ventilation was reinstituted . Patients without these features at the end of the trial were extubated . Of the 246 patients assigned to the T-tube group , 192 successfully completed the trial and were extubated ; 36 of them required reintubation . Of the 238 patients in the group receiving pressure support ventilation  , 205 were extubated and 38 of them required reintubation . The percentage of patients who remained extubated after 48 h was not different between the two groups ( 63 % T-tube , 70 % pressure support ventilation , p = 0.14 ) . The percentage of patients falling the trial was significantly higher when the T-tube was used ( 22 versus 14 % , p = 0.03 ) . Clinical evolution during the trial was not different in patients reintubated and successfully extubated . ICU mortality among reintubated patients was significantly higher than in successfully extubated patients ( 27 versus 2.6 % , p < 0.001 ) . Spontaneous breathing trials with pressure support or T-tube are suitable methods for successful discontinuation of ventilator support in patients without problems to resume spontaneous breathing Objective To evaluate the accuracy of the initial negative inspiratory pressure ( PI ) to maximal negative inspiratory pressure ( PImax ) ratio in predicting extubation outcome for intubated infants and children . Design A prospect i ve study . Setting : Pediatric intensive care unit . Patients A sample of 50 stable intubated pediatric patients who were judged clinical ly ready for extubation . Methods Using a one-way valve , PI and PImax were measured in all patients , after which the ≦ ratioPI/PImax was calculated and its accuracy in predicting extubation outcome evaluated . Measurements and results A total of 39 patients ( 78 % ) were successfully extubated and 11 patients ( 22 % ) were not . The meanPI/PImax ratio was not significantly different between extubation successes ( 0.36±0.14 ) and failures ( 0.45±0.1 ) ( P>0.05 ) . The cut-off value of 0.3 forPI/PImax identified in adult patients did not discriminate between extubation success and failure in children . Furthermore , a discriminatory cut-off value other than 0.3 could not be identified for infants and children . Conclusion ThePI/PImax ratio can not be used to predict extubation outcome in pediatric patients . Indices that predict extubation outcome in adults should not be extrapolated to infants and children before testing and validation Abstract Objective . To assess the accuracy of traditional weaning indices in predicting extubation failure , and to compare their accuracy when indices are measured at the onset of a breathing trial ( SBT ) and at the end of the SBT before extubation . Design . Prospect i ve study . Setting . Medical-surgical intensive care unit at a tertiary care hospital . Patients . Four hundred eighteen consecutive infants and children who received mechanical ventilation for at least 48 h and were deemed ready to undergo a SBT by their primary physician . Interventions .  Respiratory frequency ( RR ) , tidal volume ( VT ) , maximal inspiratory pressure ( Pimax ) and frequency-to-tidal volume ratio ( f/VT ) were obtained within the first 5 min of breathing through a T-piece . The primary physicians were unaware of those measurements and the decision to extubate a patient was made by them . RR , VT , f/VT were remeasured before extubation by the respiratory therapists . Extubation failure was defined as needing re intubation within 48 h after extubation . The area under the receiver operating characteristic ( ROC ) curve was calculated for each index as a measure of the accuracy in predicting extubation outcome . Measurements and main results . Three hundred twenty-three patients successfully underwent the SBT and were extubated , but 48 of them ( 14 % ) required re-intubation . The ROC curve for VT , RR , Pimax and f/VT measured within the first 5 min of breathing were 0.54 , 0.56 , 0.57 and 0.57 , respectively . The ROC curve did not increase significantly when the above indices were remeasured before extubation . Conclusions . In a population which had passed SBT , the ability of the traditional weaning indices to discriminate between children successfully extubated and children re-intubated is very poor BACKGROUND Traditional approaches to mechanical ventilation use tidal volumes of 10 to 15 ml per kilogram of body weight and may cause stretch-induced lung injury in patients with acute lung injury and the acute respiratory distress syndrome . We therefore conducted a trial to determine whether ventilation with lower tidal volumes would improve the clinical outcomes in these patients . METHODS Patients with acute lung injury and the acute respiratory distress syndrome were enrolled in a multicenter , r and omized trial . The trial compared traditional ventilation treatment , which involved an initial tidal volume of 12 ml per kilogram of predicted body weight and an airway pressure measured after a 0.5-second pause at the end of inspiration ( plateau pressure ) of 50 cm of water or less , with ventilation with a lower tidal volume , which involved an initial tidal volume of 6 ml per kilogram of predicted body weight and a plateau pressure of 30 cm of water or less . The primary outcomes were death before a patient was discharged home and was breathing without assistance and the number of days without ventilator use from day 1 to day 28 . RESULTS The trial was stopped after the enrollment of 861 patients because  mortality was lower in the group treated with lower tidal volumes than in the group treated with traditional tidal volumes ( 31.0 percent vs. 39.8 percent , P=0.007 ) , and the number of days without ventilator use during the first 28 days after r and omization was greater in this group ( mean [ + /-SD ] , 12+/-11 vs. 10+/-11 ; P=0.007 ) . The mean tidal volumes on days 1 to 3 were 6.2+/-0.8 and 11.8+/-0.8 ml per kilogram of predicted body weight ( P<0.001 ) , respectively , and the mean plateau pressures were 25+/-6 and 33+/-8 cm of water ( P<0.001 ) , respectively . CONCLUSIONS In patients with acute lung injury and the acute respiratory distress syndrome , mechanical ventilation with a lower tidal volume than is traditionally used results in decreased mortality and increases the number of days without ventilator use CONTEXT Despite evidence that patients with acute lung injury ( ALI ) have pulmonary surfactant dysfunction , trials of several surfactant preparations to treat adults with ALI have not been successful . Preliminary studies in children with ALI have shown that instillation of a natural lung surfactant ( calfactant ) containing high levels of surfactant-specific protein B may be beneficial . OBJECTIVE To determine if endotracheal instillation of calfactant in infants , children , and adolescents with ALI would shorten the course of respiratory failure . DESIGN , SETTING , AND PATIENTS A multicenter , r and omized , blinded trial of calfactant compared with placebo in 153 infants , children , and adolescents with respiratory failure from ALI conducted from July 2000 to July 2003 . Twenty-one tertiary care pediatric intensive care units participated . Entry criteria included age 1 week to 21 years , enrollment within 48 hours of endotracheal intubation , radiological evidence of bilateral lung disease , and an oxygenation index higher than 7 . Premature infants and children with preexisting lung , cardiac , or central nervous system disease were excluded . INTERVENTION Treatment with intratracheal instillation of 2 doses of 80 mL/m2 calfactant or an equal volume of air placebo administered 12 hours apart . MAIN OUTCOME MEASURES Ventilator-free days and mortality ; secondary outcome measures were hospital course , adverse events , and failure of conventional mechanical ventilation . RESULTS The calfactant group experienced an acute mean ( SD ) decrease in oxygenation index from 20 ( 12.9 ) to 13.9 ( 9.6 ) after 12 hours compared with the placebo group 's decrease from 20.5 ( 14.7 ) to 15.1 ( 9.0 ) ( P = .01 ) . Mortality was significantly greater in the placebo group compared with the calfactant group ( 27/75 vs 15/77 ; odds ratio , 2 
    Output:
    
agent
***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: BACKGROUND Optimal fluid management in patients with acute lung injury is unknown . Diuresis or fluid restriction may improve lung function but could jeopardize extrapulmonary-organ perfusion . METHODS In a r and omized study , we compared a conservative and a liberal strategy of fluid management using explicit protocol s applied for seven days in 1000 patients with acute lung injury . The primary end point was death at 60 days . Secondary end points included the number of ventilator-free days and organ-failure-free days and measures of lung physiology . RESULTS The rate of death at 60 days was 25.5 percent in the conservative- strategy group and 28.4 percent in the liberal- strategy group ( P=0.30 ; 95 percent confidence interval for the difference , -2.6 to 8.4 percent ) . The mean ( + /-SE ) cumulative fluid balance during the first seven days was -136+/-491 ml in the conservative- strategy group and 6992+/-502 ml in the liberal- strategy group ( P<0.001 ) . As compared with the liberal strategy , the conservative strategy improved the oxygenation index ( [ mean airway pressure x the ratio of the fraction of inspired oxygen to the partial pressure of arterial oxygen]x100 ) and the lung injury score and increased the number of ventilator-free days ( 14.6+/-0.5 vs. 12.1+/-0.5 , P<0.001 ) and days not spent in the intensive care unit ( 13.4+/-0.4 vs. 11.2+/-0.4 , P<0.001 ) during the first 28 days but did not increase the incidence or prevalence of shock during the study or the use of dialysis during the first 60 days ( 10 percent vs. 14 percent , P=0.06 ) . CONCLUSIONS Although there was no significant difference in the primary outcome of 60-day mortality , the conservative strategy of fluid management improved lung function and shortened the duration of mechanical ventilation and intensive care without increasing nonpulmonary-organ failures . These results support the use of a conservative strategy of fluid management in patients with acute lung injury . ( Clinical Trials.gov number , NCT00281268 [ Clinical Trials.gov ] . ) OBJECTIVE To determine whether dexamethasone prevents postextubation airway obstruction in young children . DESIGN Prospect i ve , r and omized , double-blind , placebo-controlled study . SETTING Pediatric intensive care unit of a university teaching hospital . PATIENTS Sixty-six children , < 5 yrs of age , intubated and mechanically ventilated for > 48 hrs . INTERVENTIONS Patients were r and omized to receive intravenous dexamethasone ( 0.5 mg/kg , maximum dose 10 mg ) or saline , every 6 hrs for six doses , beginning 6 to 12 hrs before elective extubation . MEASUREMENTS AND MAIN RESULTS Dependent variables included the presence of stridor , Croup Score , and pulsus paradoxus at 10 mins , 6 , 12 , and 24 hrs after extubation ; need for aerosolized racemic epinephrine and reintubation . The dexamethasone and placebo groups were similar in age ( median 3 months [ range 1 to 57 ] vs. 4 months [ range 1 to 59 ] , p = .6 ) , frequency of underlying airway anomalies ( 3/33 vs. 3/33 , p = 1.0 ) , and duration of mechanical ventilation ( median 3.3 days [ range 2.1 to 39 ] vs. 3.5 days [ range 2.1 to 15 ] , p = .7 ) . The dexamethasone group had a lower frequency of stridor , Croup Score , and pulsus paradoxus measurement at 10 mins and at 6 and 12 hrs after extubation . Fewer dexamethasone-treated patients required epinephrine aerosol ( 4/31 vs. 22/32 , p < .0001 ) and reintubation ( 0/31 vs. 7/32 , p < .01 ) . Three patients exited the study early-one patient in the dexamethasone group had occult gastrointestinal hemorrhage and one patient in each group had hypertension . CONCLUSION Pretreatment with dexamethasone decreases the frequency of postextubation airway obstruction in children A 2-h T-tube trial of spontaneous breathing was used in selecting patients ready for extubation and discontinuation of mechanical ventilation . However , some doubt remains as to whether it is the most appropriate method of performing a spontaneous breathing trial . We carried out a prospect i ve , r and omized , multicenter study involving patients who had received mechanical ventilation for more than 48 h and who were considered by their physicians to be ready for weaning according to clinical criteria and st and ard weaning parameters . Patients were r and omly assigned to undergo a 2-h trial of spontaneous breathing in one of two ways : with a T-tube system or with pressure support ventilation of 7 cm H2O . If a patient had signs of poor tolerance at any time during the trial , mechanical ventilation was reinstituted . Patients without these features at the end of the trial were extubated . Of the 246 patients assigned to the T-tube group , 192 successfully completed the trial and were extubated ; 36 of them required reintubation . Of the 238 patients in the group receiving pressure support ventilation  , 205 were extubated and 38 of them required reintubation . The percentage of patients who remained extubated after 48 h was not different between the two groups ( 63 % T-tube , 70 % pressure support ventilation , p = 0.14 ) . The percentage of patients falling the trial was significantly higher when the T-tube was used ( 22 versus 14 % , p = 0.03 ) . Clinical evolution during the trial was not different in patients reintubated and successfully extubated . ICU mortality among reintubated patients was significantly higher than in successfully extubated patients ( 27 versus 2.6 % , p < 0.001 ) . Spontaneous breathing trials with pressure support or T-tube are suitable methods for successful discontinuation of ventilator support in patients without problems to resume spontaneous breathing Objective To evaluate the accuracy of the initial negative inspiratory pressure ( PI ) to maximal negative inspiratory pressure ( PImax ) ratio in predicting extubation outcome for intubated infants and children . Design A prospect i ve study . Setting : Pediatric intensive care unit . Patients A sample of 50 stable intubated pediatric patients who were judged clinical ly ready for extubation . Methods Using a one-way valve , PI and PImax were measured in all patients , after which the ≦ ratioPI/PImax was calculated and its accuracy in predicting extubation outcome evaluated . Measurements and results A total of 39 patients ( 78 % ) were successfully extubated and 11 patients ( 22 % ) were not . The meanPI/PImax ratio was not significantly different between extubation successes ( 0.36±0.14 ) and failures ( 0.45±0.1 ) ( P>0.05 ) . The cut-off value of 0.3 forPI/PImax identified in adult patients did not discriminate between extubation success and failure in children . Furthermore , a discriminatory cut-off value other than 0.3 could not be identified for infants and children . Conclusion ThePI/PImax ratio can not be used to predict extubation outcome in pediatric patients . Indices that predict extubation outcome in adults should not be extrapolated to infants and children before testing and validation Abstract Objective . To assess the accuracy of traditional weaning indices in predicting extubation failure , and to compare their accuracy when indices are measured at the onset of a breathing trial ( SBT ) and at the end of the SBT before extubation . Design . Prospect i ve study . Setting . Medical-surgical intensive care unit at a tertiary care hospital . Patients . Four hundred eighteen consecutive infants and children who received mechanical ventilation for at least 48 h and were deemed ready to undergo a SBT by their primary physician . Interventions .  Respiratory frequency ( RR ) , tidal volume ( VT ) , maximal inspiratory pressure ( Pimax ) and frequency-to-tidal volume ratio ( f/VT ) were obtained within the first 5 min of breathing through a T-piece . The primary physicians were unaware of those measurements and the decision to extubate a patient was made by them . RR , VT , f/VT were remeasured before extubation by the respiratory therapists . Extubation failure was defined as needing re intubation within 48 h after extubation . The area under the receiver operating characteristic ( ROC ) curve was calculated for each index as a measure of the accuracy in predicting extubation outcome . Measurements and main results . Three hundred twenty-three patients successfully underwent the SBT and were extubated , but 48 of them ( 14 % ) required re-intubation . The ROC curve for VT , RR , Pimax and f/VT measured within the first 5 min of breathing were 0.54 , 0.56 , 0.57 and 0.57 , respectively . The ROC curve did not increase significantly when the above indices were remeasured before extubation . Conclusions . In a population which had passed SBT , the ability of the traditional weaning indices to discriminate between children successfully extubated and children re-intubated is very poor BACKGROUND Traditional approaches to mechanical ventilation use tidal volumes of 10 to 15 ml per kilogram of body weight and may cause stretch-induced lung injury in patients with acute lung injury and the acute respiratory distress syndrome . We therefore conducted a trial to determine whether ventilation with lower tidal volumes would improve the clinical outcomes in these patients . METHODS Patients with acute lung injury and the acute respiratory distress syndrome were enrolled in a multicenter , r and omized trial . The trial compared traditional ventilation treatment , which involved an initial tidal volume of 12 ml per kilogram of predicted body weight and an airway pressure measured after a 0.5-second pause at the end of inspiration ( plateau pressure ) of 50 cm of water or less , with ventilation with a lower tidal volume , which involved an initial tidal volume of 6 ml per kilogram of predicted body weight and a plateau pressure of 30 cm of water or less . The primary outcomes were death before a patient was discharged home and was breathing without assistance and the number of days without ventilator use from day 1 to day 28 . RESULTS The trial was stopped after the enrollment of 861 patients because  mortality was lower in the group treated with lower tidal volumes than in the group treated with traditional tidal volumes ( 31.0 percent vs. 39.8 percent , P=0.007 ) , and the number of days without ventilator use during the first 28 days after r and omization was greater in this group ( mean [ + /-SD ] , 12+/-11 vs. 10+/-11 ; P=0.007 ) . The mean tidal volumes on days 1 to 3 were 6.2+/-0.8 and 11.8+/-0.8 ml per kilogram of predicted body weight ( P<0.001 ) , respectively , and the mean plateau pressures were 25+/-6 and 33+/-8 cm of water ( P<0.001 ) , respectively . CONCLUSIONS In patients with acute lung injury and the acute respiratory distress syndrome , mechanical ventilation with a lower tidal volume than is traditionally used results in decreased mortality and increases the number of days without ventilator use CONTEXT Despite evidence that patients with acute lung injury ( ALI ) have pulmonary surfactant dysfunction , trials of several surfactant preparations to treat adults with ALI have not been successful . Preliminary studies in children with ALI have shown that instillation of a natural lung surfactant ( calfactant ) containing high levels of surfactant-specific protein B may be beneficial . OBJECTIVE To determine if endotracheal instillation of calfactant in infants , children , and adolescents with ALI would shorten the course of respiratory failure . DESIGN , SETTING , AND PATIENTS A multicenter , r and omized , blinded trial of calfactant compared with placebo in 153 infants , children , and adolescents with respiratory failure from ALI conducted from July 2000 to July 2003 . Twenty-one tertiary care pediatric intensive care units participated . Entry criteria included age 1 week to 21 years , enrollment within 48 hours of endotracheal intubation , radiological evidence of bilateral lung disease , and an oxygenation index higher than 7 . Premature infants and children with preexisting lung , cardiac , or central nervous system disease were excluded . INTERVENTION Treatment with intratracheal instillation of 2 doses of 80 mL/m2 calfactant or an equal volume of air placebo administered 12 hours apart . MAIN OUTCOME MEASURES Ventilator-free days and mortality ; secondary outcome measures were hospital course , adverse events , and failure of conventional mechanical ventilation . RESULTS The calfactant group experienced an acute mean ( SD ) decrease in oxygenation index from 20 ( 12.9 ) to 13.9 ( 9.6 ) after 12 hours compared with the placebo group 's decrease from 20.5 ( 14.7 ) to 15.1 ( 9.0 ) ( P = .01 ) . Mortality was significantly greater in the placebo group compared with the calfactant group ( 27/75 vs 15/77 ; odds ratio , 2 
    Output:
    