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: Objective To evaluate the incidence , treatment and mortality of  acute respiratory failure ( ARF ) in Finnish intensive care units ( ICUs ) . Study design Prospect i ve multicentre cohort study . Methods All adult patients in 25 ICUs were screened for use of invasive or non-invasive ventilatory support during an 8-week period . Patients needing ventilatory support for more than 6 h were included and defined as ARF patients . Risk factors for ARF and details of prior chronic health status were assessed .  Ventilatory and concomitant treatments  were evaluated and recorded daily throughout the ICU stay . ICU and 90-day mortalities were assessed . Results A total of 958 ( 39 % ) from the 2,473 admitted patients were treated with ventilatory support for more than 6 h. Incidence of ARF , acute lung injury ( ALI ) and acute respiratory distress syndrome ( ARDS ) was 149.5 , 10.6 and 5.0/100,000 per year , respectively . Ventilatory support was started with non-invasive interfaces in 183 of 958 ( 19 % ) patients . Ventilatory modes allowing triggering of spontaneous breaths were preferred ( 81 % ) . Median tidal volume/predicted body weight was 8.7 ( 7.6–9.9 ) ml/kg and plateau pressure 19 ( 16–23 ) cmH2O . The 90-day mortality of ARF was 31 % . Conclusions While the incidence of ARF requiring ventilatory support is higher , the incidence of ALI and ARDS seems to be lower in Finl and than previously reported in other countries . Tidal volumes are higher than recommended in the concept of lung protective strategy . However , restriction of peak airway pressure was used in the majority of ARF patients 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 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 . 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 In acute increased-permeability edema , the Bohr physiological dead space ( VD/VTCO2 ) can be influenced by changes in anatomic dead space , ventilation-perfusion ( VA/Q ) heterogeneity , shunt , and the Haldane effect . We used the multiple inert gas elimination technique to assess the effect of positive end-expiratory pressure ( PEEP ) on each of these components of VD/VTCO2 in 14 pentobarbital-anesthetized dogs with increased permeability edema induced by infused oleic acid . PEEP of 5 , 10 , 15 , and 20 cmH2O was applied in r and om sequence . Following injury VD/VTCO2 increased . It decreased with 5 or 10 cmH2O PEEP but increased progressively at higher PEEP levels . The decrease in VD/VTCO2 at 5 or 10 cmH2O PEEP was due to reductions in shunt and midrange VA/Q heterogeneity . The increase in VD/VTCO2 that occurred with higher PEEP levels was due to increased ventilation to high VA/Q regions and a larger anatomic dead space . Haldane effect magnified the shunt component of VD/VTCO2 but reduced the influence of midrange VA/Q heterogeneity 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 . Initial oxygenation improved more in the decremental PEEP titration group than in the control group . However , dynamic compliance , tidal volume and PEEP were similar in the two groups during the first week . The duration of use of paralysing or sedative agents , mechanical ventilation , stay in the intensive care unit and mortality at 28 days did not differ significantly between the decremental PEEP titration and control groups . Conclusions The daily decremental PEEP titration after ARM showed only initial oxygenation improvement compared with the table-based PEEP method . Respiratory mechanics and patient outcomes did not differ between the decremental PEEP titration and control groups . Trial registration Clinical Trials.gov identifier : IS RCT N79027921 BACKGROUND In the acute respiratory distress syndrome ( ARDS ) , positive end-expiratory pressure ( PEEP ) may decrease ventilator-induced lung injury by keeping lung regions open that otherwise would be collapsed . Since the effects of PEEP probably depend on the recruitability of lung tissue , we conducted a study to examine the relationship between the percentage of potentially recruitable lung , as indicated by computed tomography ( CT ) , and the clinical and physiological effects of PEEP . METHODS Sixty-eight patients with acute lung injury or ARDS underwent whole-lung CT during breath-holding sessions at airway pressures of 5 , 15 , and 45 cm of water . The percentage of potentially recruitable lung was defined as the proportion of lung tissue in which aeration was restored at airway pressures between 5 and 45 cm of water . RESULTS The percentage of potentially recruitable lung varied widely in the population , accounting for a mean ( + /-SD ) of 13+/-11 percent of the lung weight , and was highly correlated with the percentage of lung tissue in which aeration was maintained after the application of PEEP ( r2=0.72 , P<0.001 ) . On average , 24 percent of the lung could not be recruited . Patients with a higher percentage of potentially recruitable lung ( greater than the median value of 9 percent ) had greater total lung weights ( P<0.001 ) , poorer oxygenation 
    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: Objective To evaluate the incidence , treatment and mortality of  acute respiratory failure ( ARF ) in Finnish intensive care units ( ICUs ) . Study design Prospect i ve multicentre cohort study . Methods All adult patients in 25 ICUs were screened for use of invasive or non-invasive ventilatory support during an 8-week period . Patients needing ventilatory support for more than 6 h were included and defined as ARF patients . Risk factors for ARF and details of prior chronic health status were assessed .  Ventilatory and concomitant treatments  were evaluated and recorded daily throughout the ICU stay . ICU and 90-day mortalities were assessed . Results A total of 958 ( 39 % ) from the 2,473 admitted patients were treated with ventilatory support for more than 6 h. Incidence of ARF , acute lung injury ( ALI ) and acute respiratory distress syndrome ( ARDS ) was 149.5 , 10.6 and 5.0/100,000 per year , respectively . Ventilatory support was started with non-invasive interfaces in 183 of 958 ( 19 % ) patients . Ventilatory modes allowing triggering of spontaneous breaths were preferred ( 81 % ) . Median tidal volume/predicted body weight was 8.7 ( 7.6–9.9 ) ml/kg and plateau pressure 19 ( 16–23 ) cmH2O . The 90-day mortality of ARF was 31 % . Conclusions While the incidence of ARF requiring ventilatory support is higher , the incidence of ALI and ARDS seems to be lower in Finl and than previously reported in other countries . Tidal volumes are higher than recommended in the concept of lung protective strategy . However , restriction of peak airway pressure was used in the majority of ARF patients 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 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 . 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 In acute increased-permeability edema , the Bohr physiological dead space ( VD/VTCO2 ) can be influenced by changes in anatomic dead space , ventilation-perfusion ( VA/Q ) heterogeneity , shunt , and the Haldane effect . We used the multiple inert gas elimination technique to assess the effect of positive end-expiratory pressure ( PEEP ) on each of these components of VD/VTCO2 in 14 pentobarbital-anesthetized dogs with increased permeability edema induced by infused oleic acid . PEEP of 5 , 10 , 15 , and 20 cmH2O was applied in r and om sequence . Following injury VD/VTCO2 increased . It decreased with 5 or 10 cmH2O PEEP but increased progressively at higher PEEP levels . The decrease in VD/VTCO2 at 5 or 10 cmH2O PEEP was due to reductions in shunt and midrange VA/Q heterogeneity . The increase in VD/VTCO2 that occurred with higher PEEP levels was due to increased ventilation to high VA/Q regions and a larger anatomic dead space . Haldane effect magnified the shunt component of VD/VTCO2 but reduced the influence of midrange VA/Q heterogeneity 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 . Initial oxygenation improved more in the decremental PEEP titration group than in the control group . However , dynamic compliance , tidal volume and PEEP were similar in the two groups during the first week . The duration of use of paralysing or sedative agents , mechanical ventilation , stay in the intensive care unit and mortality at 28 days did not differ significantly between the decremental PEEP titration and control groups . Conclusions The daily decremental PEEP titration after ARM showed only initial oxygenation improvement compared with the table-based PEEP method . Respiratory mechanics and patient outcomes did not differ between the decremental PEEP titration and control groups . Trial registration Clinical Trials.gov identifier : IS RCT N79027921 BACKGROUND In the acute respiratory distress syndrome ( ARDS ) , positive end-expiratory pressure ( PEEP ) may decrease ventilator-induced lung injury by keeping lung regions open that otherwise would be collapsed . Since the effects of PEEP probably depend on the recruitability of lung tissue , we conducted a study to examine the relationship between the percentage of potentially recruitable lung , as indicated by computed tomography ( CT ) , and the clinical and physiological effects of PEEP . METHODS Sixty-eight patients with acute lung injury or ARDS underwent whole-lung CT during breath-holding sessions at airway pressures of 5 , 15 , and 45 cm of water . The percentage of potentially recruitable lung was defined as the proportion of lung tissue in which aeration was restored at airway pressures between 5 and 45 cm of water . RESULTS The percentage of potentially recruitable lung varied widely in the population , accounting for a mean ( + /-SD ) of 13+/-11 percent of the lung weight , and was highly correlated with the percentage of lung tissue in which aeration was maintained after the application of PEEP ( r2=0.72 , P<0.001 ) . On average , 24 percent of the lung could not be recruited . Patients with a higher percentage of potentially recruitable lung ( greater than the median value of 9 percent ) had greater total lung weights ( P<0.001 ) , poorer oxygenation 
    Output:
    