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: CONTEXT The need for lung protection is universally accepted , but the optimal level of positive end-expiratory pressure ( PEEP ) in patients with acute lung injury ( ALI ) or acute respiratory distress syndrome remains debated . OBJECTIVE To compare the effect on outcome of a strategy for setting PEEP aim ed at increasing alveolar recruitment while limiting hyperinflation to one aim ed at minimizing alveolar distension in patients with ALI . DESIGN , SETTING , AND PATIENTS A multicenter r and omized controlled trial of 767 adults ( mean [ SD ] age , 59.9 [ 15.4 ] years ) with ALI conducted in 37 intensive care units in France from September 2002 to December 2005 . INTERVENTION Tidal volume was set at 6 mL/kg of predicted body weight in both strategies . Patients were r and omly assigned to a moderate PEEP strategy ( 5 - 9 cm H(2)O ) ( minimal distension strategy ; n = 382 ) or to a level of PEEP set to reach a plateau pressure of 28 to 30 cm H(2)O ( increased recruitment strategy ; n = 385 ) . MAIN OUTCOME MEASURES The primary end point was mortality at 28 days . Secondary end points were hospital mortality at 60 days , ventilator-free days , and organ failure-free days at 28 days . RESULTS The 28-day mortality rate in the minimal distension group was 31.2 % ( n = 119 ) vs 27.8 % ( n = 107 ) in the increased recruitment group ( relative risk , 1.12 [ 95 % confidence interval , 0.90 - 1.40 ] ; P = .31 ) . The hospital mortality rate in the minimal distension group was 39.0 % ( n = 149 ) vs 35.4 % ( n = 136 ) in the increased recruitment group ( relative risk , 1.10 [ 95 % confidence interval , 0.92 - 1.32 ] ; P = .30 ) . The increased recruitment group compared with the minimal distension group had a higher median number of ventilator-free days ( 7 [ interquartile range { IQR } , 0 - 19 ] vs 3 [ IQR , 0 - 17 ] ; P = .04 ) and organ failure-free days ( 6 [ IQR , 0 - 18 ] vs 2 [ IQR , 0 - 16 ] ; P = .04 ) . This strategy also was associated with higher compliance values , better oxygenation , less use of adjunctive therapies , and larger fluid requirements . CONCLUSIONS A strategy for setting PEEP aim ed at increasing alveolar recruitment while limiting hyperinflation did not significantly reduce mortality . However , it did improve lung function and reduced the duration of mechanical ventilation and the duration of organ failure . TRIAL REGISTRATION clinical trials.gov Identifier : NCT00188058 OBJECTIVE To investigate the significance and effect of pressure controlled ventilation ( PCV ) as well as volume controlled ventilation ( VCV ) by lung protective strategy on respiratory mechanics , blood gas analysis and hemodynamics in patients with acute respiratory distress syndrome ( ARDS ) . METHODS Fifty patients with ARDS were r and omly divided into PCV and VCV groups with permissive hypercapnia and open lung strategy . Changes in respiratory mechanics , blood gas analysis and hemodynamics were compared between two groups . RESULTS Peak inspiration pressure ( PIP ) in PCV group was significantly lower than that in VCV group , while mean pressure of airway ( MPaw ) was significantly higher than that in VCV after 24 hours mechanical ventilation . After 24 hours mechanical ventilation , there were higher central venous pressure ( CVP ) and slower heart rate ( HR ) in two groups , CVP was significantly higher in VCV compared with PCV , and PCV group had slower HR than VCV group , the two groups had no differences in mean blood pressure ( MBP ) at various intervals . All patients showed no ventilator-induced lung injury . Arterial blood oxygenations were obviously improved in two groups after 24 hours mechanical ventilation , PCV group had better partial pressure of oxygen in artery ( PaO2 ) than VCV group . CONCLUSION Both PCV and VCV can improve arterial blood oxygenations , prevent ventilator-induced lung injury , and have less disturbance in hemodynamic parameters .  PCV with lung protective ventilatory strategy should be early use for patients with ARDS BACKGROUND Survival of patients with acute lung injury or the acute respiratory distress syndrome ( ARDS ) has been improved by ventilation with small tidal volumes and the use of positive end-expiratory pressure ( PEEP ) ; however , the optimal level of PEEP has been difficult to determine . In this pilot study , we estimated transpulmonary pressure with the use of esophageal balloon catheters . We reasoned that the use of pleural-pressure measurements , despite the technical limitations to the accuracy of such measurements , would enable us to find a PEEP value that could maintain oxygenation while preventing lung injury due to repeated alveolar collapse or overdistention . METHODS We r and omly assigned patients with acute lung injury or ARDS to undergo mechanical ventilation with PEEP adjusted according to measurements of esophageal pressure ( the esophageal-pressure-guided group ) or according to the Acute Respiratory Distress Syndrome Network st and ard-of-care recommendations ( the control group ) . The primary end point was improvement in oxygenation . The secondary end points included respiratory-system compliance and patient outcomes . RESULTS The study reached its stopping criterion and was terminated after 61 patients had been enrolled . The ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen at 72 hours was 88 mm Hg higher in the esophageal-pressure-guided group than in the control group ( 95 % confidence interval , 78.1 to 98.3 ; P=0.002 ) . This effect was persistent over the entire follow-up time ( at 24 , 48 , and 72 hours ; P=0.001 by repeated- measures analysis of variance ) . Respiratory-system compliance was also significantly better at 24 , 48 , and 72 hours in the esophageal-pressure-guided group ( P=0.01 by repeated- measures analysis of variance ) . CONCLUSIONS As compared with the current st and ard of care , a ventilator strategy using esophageal pressures to estimate the transpulmonary pressure significantly improves oxygenation and compliance . Multicenter clinical trials are needed to determine whether this approach should be widely adopted . ( Clinical Trials.gov number , NCT00127491 . Objective To evaluate the feasibility of airway pressure release ventilation ( APRV ) in providing ventilatory support to patients with acute lung injury of diverse etiology and mild-to-moderate severity . Design Prospect i ve , multicenter , nonr and omized crossover trial . Setting ICUs in six major referral hospitals . Patients Fifty adult patients with respiratory failure requiring mechanical ventilation and positive end-expiratory airway pressure . Interventions After optimization of continuous positive airway pressure ( CPAP ) , conventional ventilation and APRV were administered sequentially for 30 mins . During APRV , the CPAP level and airway pressure release level were adjusted to prevent hypoxemia , while the degree of ventilatory support was adjusted by altering the frequency of pressure release . Measurements and Main Results Circulatory and ventilatory pressures , arterial blood gases and pH , heart rate , and respiratory rate were measured . Alveolar ventilation was augmented adequately in 47 of 50 patients by APRV . Adjustment of APRV required an increase in mean CPAP from 13 ± 3 ( SD ) to 21 ± 9 cm H2O and a release pressure of 6 ± 5 cm H2O . This airway pressure pattern produced a mean airway pressure comparable to that pressure achieved during conventional ventilation . Failure of APRV in three patients could be attributed to an inadequate level of CPAP or an inadequate APRV rate . While maintaining oxygenation of arterial blood and circulatory function  , APRV allowed a substantial ( 55 ± 17 % ; p < .0001 ) reduction in peak airway pressure compared with conventional positive pressure ventilation adjusted to deliver a comparable or lower level of ventilatory support . Conclusions APRV is a feasible alternative to conventional mechanical ventilation for augmentation of alveolar ventilation in patients with acute lung injury of mild-to-moderate severity OBJECTIVE : This population -based , prospect i ve , cohort study was design ed to determine the population incidence and outcomes of pediatric acute lung injury . METHODS : Between 1999 and 2000 , 1 year of screening was performed at all hospitals admitting critically ill children in King County , Washington . County residents 0.5 to 15 years of age who required invasive ( through endotracheal tube or tracheostomy ) or noninvasive ( through full face mask ) mechanical ventilation , regardless of the duration of mechanical ventilation , were screened . From this population , children meeting North American-European Consensus Conference acute lung injury criteria were eligible for enrollment . Postoperative patients who received mechanical ventilation for < 24 hours were excluded . Data collected included the presence of predefined cardiac conditions , demographic and physiological data , duration of mechanical ventilation , and deaths . US Census population figures were used to estimate incidence . Associations between outcomes and subgroups identified a priori were assessed . RESULTS : Thirty-nine children met the criteria for acute lung injury , result ing in a calculated incidence of 12.8 cases per 100000 person-years . Severe sepsis ( with pneumonia as the infection focus ) was the most common risk factor . The median 24-hour Pediatric Risk of Mortality III score was 9.0 , and the mean ± SD was 11.7 ± 7.5 . The hospital mortality rate was 18 % , lower than that reported previously for pediatric acute lung injury . There were no statistically significant associations between age , gender , or risk factors and outcomes . CONCLUSIONS : We present the first population -based estimate of pediatric acute lung injury incidence in the United States . Population incidence and mortality rates are lower than those for adult acute lung injury . Low mortality rates in pediatric acute lung injury may necessitate clinical trial outcome measures other than death 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 Introduction In acute respiratory distress syndrome ( ARDS ) , adequate positive end-expiratory pressure ( PEEP ) may decrease ventilator-induced lung injury by minimising overinflation and cyclic recruitment-derecruitment of the lung . We evaluated whether setting the PEEP using decremental PEEP titration after an alveolar recruitment manoeuvre ( ARM ) affects the clinical outcome in patients with ARDS . Methods Fifty-seven patients with early ARDS were r and omly assigned to a group given decremental PEEP titration following ARM or a table-based PEEP ( control ) group . PEEP  and  inspired fraction of oxygen ( FiO2 )  in the control group were set according to the table-based combinations of FiO2 and PEEP of the ARDS network , by which we aim ed to achieve a PEEP level compatible with an oxygenation target . In the decremental PEEP titration group , the oxygen saturation and static compliance were monitored as the patients performed the ARM along with the extended sigh method , which is design ed to gradually apply and withdraw a high distending pressure over a prolonged period , and the decremental titration of PEEP . Results The baseline characteristics did not differ significantly between the control and decremental PEEP titration groups 
    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: CONTEXT The need for lung protection is universally accepted , but the optimal level of positive end-expiratory pressure ( PEEP ) in patients with acute lung injury ( ALI ) or acute respiratory distress syndrome remains debated . OBJECTIVE To compare the effect on outcome of a strategy for setting PEEP aim ed at increasing alveolar recruitment while limiting hyperinflation to one aim ed at minimizing alveolar distension in patients with ALI . DESIGN , SETTING , AND PATIENTS A multicenter r and omized controlled trial of 767 adults ( mean [ SD ] age , 59.9 [ 15.4 ] years ) with ALI conducted in 37 intensive care units in France from September 2002 to December 2005 . INTERVENTION Tidal volume was set at 6 mL/kg of predicted body weight in both strategies . Patients were r and omly assigned to a moderate PEEP strategy ( 5 - 9 cm H(2)O ) ( minimal distension strategy ; n = 382 ) or to a level of PEEP set to reach a plateau pressure of 28 to 30 cm H(2)O ( increased recruitment strategy ; n = 385 ) . MAIN OUTCOME MEASURES The primary end point was mortality at 28 days . Secondary end points were hospital mortality at 60 days , ventilator-free days , and organ failure-free days at 28 days . RESULTS The 28-day mortality rate in the minimal distension group was 31.2 % ( n = 119 ) vs 27.8 % ( n = 107 ) in the increased recruitment group ( relative risk , 1.12 [ 95 % confidence interval , 0.90 - 1.40 ] ; P = .31 ) . The hospital mortality rate in the minimal distension group was 39.0 % ( n = 149 ) vs 35.4 % ( n = 136 ) in the increased recruitment group ( relative risk , 1.10 [ 95 % confidence interval , 0.92 - 1.32 ] ; P = .30 ) . The increased recruitment group compared with the minimal distension group had a higher median number of ventilator-free days ( 7 [ interquartile range { IQR } , 0 - 19 ] vs 3 [ IQR , 0 - 17 ] ; P = .04 ) and organ failure-free days ( 6 [ IQR , 0 - 18 ] vs 2 [ IQR , 0 - 16 ] ; P = .04 ) . This strategy also was associated with higher compliance values , better oxygenation , less use of adjunctive therapies , and larger fluid requirements . CONCLUSIONS A strategy for setting PEEP aim ed at increasing alveolar recruitment while limiting hyperinflation did not significantly reduce mortality . However , it did improve lung function and reduced the duration of mechanical ventilation and the duration of organ failure . TRIAL REGISTRATION clinical trials.gov Identifier : NCT00188058 OBJECTIVE To investigate the significance and effect of pressure controlled ventilation ( PCV ) as well as volume controlled ventilation ( VCV ) by lung protective strategy on respiratory mechanics , blood gas analysis and hemodynamics in patients with acute respiratory distress syndrome ( ARDS ) . METHODS Fifty patients with ARDS were r and omly divided into PCV and VCV groups with permissive hypercapnia and open lung strategy . Changes in respiratory mechanics , blood gas analysis and hemodynamics were compared between two groups . RESULTS Peak inspiration pressure ( PIP ) in PCV group was significantly lower than that in VCV group , while mean pressure of airway ( MPaw ) was significantly higher than that in VCV after 24 hours mechanical ventilation . After 24 hours mechanical ventilation , there were higher central venous pressure ( CVP ) and slower heart rate ( HR ) in two groups , CVP was significantly higher in VCV compared with PCV , and PCV group had slower HR than VCV group , the two groups had no differences in mean blood pressure ( MBP ) at various intervals . All patients showed no ventilator-induced lung injury . Arterial blood oxygenations were obviously improved in two groups after 24 hours mechanical ventilation , PCV group had better partial pressure of oxygen in artery ( PaO2 ) than VCV group . CONCLUSION Both PCV and VCV can improve arterial blood oxygenations , prevent ventilator-induced lung injury , and have less disturbance in hemodynamic parameters .  PCV with lung protective ventilatory strategy should be early use for patients with ARDS BACKGROUND Survival of patients with acute lung injury or the acute respiratory distress syndrome ( ARDS ) has been improved by ventilation with small tidal volumes and the use of positive end-expiratory pressure ( PEEP ) ; however , the optimal level of PEEP has been difficult to determine . In this pilot study , we estimated transpulmonary pressure with the use of esophageal balloon catheters . We reasoned that the use of pleural-pressure measurements , despite the technical limitations to the accuracy of such measurements , would enable us to find a PEEP value that could maintain oxygenation while preventing lung injury due to repeated alveolar collapse or overdistention . METHODS We r and omly assigned patients with acute lung injury or ARDS to undergo mechanical ventilation with PEEP adjusted according to measurements of esophageal pressure ( the esophageal-pressure-guided group ) or according to the Acute Respiratory Distress Syndrome Network st and ard-of-care recommendations ( the control group ) . The primary end point was improvement in oxygenation . The secondary end points included respiratory-system compliance and patient outcomes . RESULTS The study reached its stopping criterion and was terminated after 61 patients had been enrolled . The ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen at 72 hours was 88 mm Hg higher in the esophageal-pressure-guided group than in the control group ( 95 % confidence interval , 78.1 to 98.3 ; P=0.002 ) . This effect was persistent over the entire follow-up time ( at 24 , 48 , and 72 hours ; P=0.001 by repeated- measures analysis of variance ) . Respiratory-system compliance was also significantly better at 24 , 48 , and 72 hours in the esophageal-pressure-guided group ( P=0.01 by repeated- measures analysis of variance ) . CONCLUSIONS As compared with the current st and ard of care , a ventilator strategy using esophageal pressures to estimate the transpulmonary pressure significantly improves oxygenation and compliance . Multicenter clinical trials are needed to determine whether this approach should be widely adopted . ( Clinical Trials.gov number , NCT00127491 . Objective To evaluate the feasibility of airway pressure release ventilation ( APRV ) in providing ventilatory support to patients with acute lung injury of diverse etiology and mild-to-moderate severity . Design Prospect i ve , multicenter , nonr and omized crossover trial . Setting ICUs in six major referral hospitals . Patients Fifty adult patients with respiratory failure requiring mechanical ventilation and positive end-expiratory airway pressure . Interventions After optimization of continuous positive airway pressure ( CPAP ) , conventional ventilation and APRV were administered sequentially for 30 mins . During APRV , the CPAP level and airway pressure release level were adjusted to prevent hypoxemia , while the degree of ventilatory support was adjusted by altering the frequency of pressure release . Measurements and Main Results Circulatory and ventilatory pressures , arterial blood gases and pH , heart rate , and respiratory rate were measured . Alveolar ventilation was augmented adequately in 47 of 50 patients by APRV . Adjustment of APRV required an increase in mean CPAP from 13 ± 3 ( SD ) to 21 ± 9 cm H2O and a release pressure of 6 ± 5 cm H2O . This airway pressure pattern produced a mean airway pressure comparable to that pressure achieved during conventional ventilation . Failure of APRV in three patients could be attributed to an inadequate level of CPAP or an inadequate APRV rate . While maintaining oxygenation of arterial blood and circulatory function  , APRV allowed a substantial ( 55 ± 17 % ; p < .0001 ) reduction in peak airway pressure compared with conventional positive pressure ventilation adjusted to deliver a comparable or lower level of ventilatory support . Conclusions APRV is a feasible alternative to conventional mechanical ventilation for augmentation of alveolar ventilation in patients with acute lung injury of mild-to-moderate severity OBJECTIVE : This population -based , prospect i ve , cohort study was design ed to determine the population incidence and outcomes of pediatric acute lung injury . METHODS : Between 1999 and 2000 , 1 year of screening was performed at all hospitals admitting critically ill children in King County , Washington . County residents 0.5 to 15 years of age who required invasive ( through endotracheal tube or tracheostomy ) or noninvasive ( through full face mask ) mechanical ventilation , regardless of the duration of mechanical ventilation , were screened . From this population , children meeting North American-European Consensus Conference acute lung injury criteria were eligible for enrollment . Postoperative patients who received mechanical ventilation for < 24 hours were excluded . Data collected included the presence of predefined cardiac conditions , demographic and physiological data , duration of mechanical ventilation , and deaths . US Census population figures were used to estimate incidence . Associations between outcomes and subgroups identified a priori were assessed . RESULTS : Thirty-nine children met the criteria for acute lung injury , result ing in a calculated incidence of 12.8 cases per 100000 person-years . Severe sepsis ( with pneumonia as the infection focus ) was the most common risk factor . The median 24-hour Pediatric Risk of Mortality III score was 9.0 , and the mean ± SD was 11.7 ± 7.5 . The hospital mortality rate was 18 % , lower than that reported previously for pediatric acute lung injury . There were no statistically significant associations between age , gender , or risk factors and outcomes . CONCLUSIONS : We present the first population -based estimate of pediatric acute lung injury incidence in the United States . Population incidence and mortality rates are lower than those for adult acute lung injury . Low mortality rates in pediatric acute lung injury may necessitate clinical trial outcome measures other than death 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 Introduction In acute respiratory distress syndrome ( ARDS ) , adequate positive end-expiratory pressure ( PEEP ) may decrease ventilator-induced lung injury by minimising overinflation and cyclic recruitment-derecruitment of the lung . We evaluated whether setting the PEEP using decremental PEEP titration after an alveolar recruitment manoeuvre ( ARM ) affects the clinical outcome in patients with ARDS . Methods Fifty-seven patients with early ARDS were r and omly assigned to a group given decremental PEEP titration following ARM or a table-based PEEP ( control ) group . PEEP  and  inspired fraction of oxygen ( FiO2 )  in the control group were set according to the table-based combinations of FiO2 and PEEP of the ARDS network , by which we aim ed to achieve a PEEP level compatible with an oxygenation target . In the decremental PEEP titration group , the oxygen saturation and static compliance were monitored as the patients performed the ARM along with the extended sigh method , which is design ed to gradually apply and withdraw a high distending pressure over a prolonged period , and the decremental titration of PEEP . Results The baseline characteristics did not differ significantly between the control and decremental PEEP titration groups 
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