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 assess how the level of positive end-expiratory pressure ( PEEP ) ( antiderecruitment strategy ) , etiological category of diffuse lung injury , and body position of the patient modify the effect of the alveolar recruitment maneuver ( ARM ) in acute respiratory distress syndrome ( ARDS ) . Design Prospect i ve clinical trial . Setting Medical intensive care unit at a tertiary hospital . Patients Forty-seven patients with early ARDS , including 19 patients from our preliminary study . InterventionFrom baseline ventilation at a tidal volume of 8 mL/kg and PEEP of 10 cm H2O , the ARM ( a stepwise increase in the level of PEEP up to 30 cm H2O with a concomitant decrease in the magnitude of tidal volume down to 2 mL/kg ) was given with ( ARM + PEEP , n = 20 ) or without ( ARM only , n = 19 ) subsequent increase of PEEP to 15 cm H2O . In eight other patients , PEEP was increased to 15 cm H2O without a preceding ARM ( PEEP only ) . Measurements and Results In all three groups , Pao2 was increased by the respective intervention ( all p < .05 ) . In the ARM-only group , Pao2 at 15 mins after intervention was lower than Pao2 immediate after intervention ( p = .046 ) . In the ARM + PEEP group , no such decrease in Pao2 was observed , and Pao2 at 15 , 30 , 45 , and 60 mins after intervention was higher than in the ARM-only group ( all p < .05 ) . Compared with the PEEP-only group , Pao2 of the ARM + PEEP group was higher immediately after intervention and at the later time points ( all p < .05 ) . Compared with patients with ARDS associated with direct lung injury ( pulmonary ARDS ) , patients with ARDS associated with indirect lung injury ( extrapulmonary ARDS ) showed a greater increase in Pao2 ( 27 ± 21 % vs. 130 ± 112%;p = .002 ) and a greater decrease in radiologic scores ( 1.0 ± 2.4 vs. 3.4 ± 1.5;p = .005 ) after the ARM . The increase in Pao2 induced by the ARM was greater for patients in the supine position than for patients in the prone position ( 61 ± 82 % vs. 21 ± 14%;p = .028 ) . Consequently , Pao2 immediately after the ARM was similar in the two groups of patients in different positions . Conclusions After the ARM , a sufficient level of PEEP is required as an antiderecruitment strategy . Pulmonary ARDS and extrapulmonary ARDS may be different pathophysiologic entities . An effective ARM may obviate the need for the prone position in ARDS at least in terms of oxygenation Objective To assess the acute effect of a lung recruitment maneuver ( LRM ) on lung morphology in patients with acute lung injury ( ALI ) or acute respiratory distress syndrome ( ARDS ) . Patients Ten patients with ALI/ARDS on mechanical ventilation . Design Prospect i ve clinical study . Setting Computed tomography ( CT ) scan facility in a teaching hospital . Interventions An LRM performed by stepwise increases in positive end-expiratory pressure ( PEEP ) of up to 30–40 cmH2O . Lung basal CT sections were taken at end-expiration ( patients 1 to 5 ) , and at end-expiration and end-inspiration ( patients 6 to10 ) . Arterial blood gases and static compliance ( Cst ) were measured before , during and after the LRM . Measurements and main results Poorly aerated and non-aerated tissue at PEEP 10 cmH2O accounted for 60.0±29.1 % of lung parenchyma , while only 1.1±1.8 % was hyperinflated . Increasing PEEP to 20 and 30 cmH2O , compared to PEEP 10 cmH2O , decreased poorly aerated and non-aerated tissue by 16.2±28.0 % and 33.4±13.8 % , respectively ( p<0.05 ) . This was associated with an increase in PaO2 and a decrease in total static compliance . Inspiration increased alveolar recruitment at all PEEP levels . Hyperinflated tissue increased up to 2.9±4.0 % with PEEP 30 cmH2O , and to a lesser degree with inspiration . No barotrauma or severe hypotension occurred . Conclusions Lung recruitment maneuvers improve oxygenation by exp and ing collapsed alveoli without inducing too much hyperinflation in ALI/ARDS patients .  An LRM during the CT scan gives morphologic and functional information that could be useful in setting ventilatory parameters 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 BACKGROUND There are reports of rigors and /or clinical deterioration following recruitment maneuvers ( RMs ) , leading us to question whether the use of sustained high-pressure inflation could lead to release of inflammatory mediators . METHODS Prospect i ve cohort study of 26 patients with ARDS receiving mechanical ventilation . A single RM was performed during which the mean airway pressure was increased to 40 cm H2O and held constant for a period of 30 s. The concentration of nine cytokines ( interleukin [IL]-1 , IL-6 , IL-8 , IL-10 , tumor necrosis factor [TNF]-alpha , Fas lig and , vascular endothelial growth factor , TNF receptor 1 , TNF receptor 2 ) was measured longitudinally at three time points : prior to initiation of the RM , 5 min after the RM , and 60 min after the RM . RESULTS RMs were tolerated well from a hemodynamic perspective . Oxygenation improved as reflected by an increased Pao2/fraction of inspired oxygen ( Fio2 ) ratio from 140+/-49 at baseline to 190+/-78 ( mean+/-SD ) at 5 min after the RM ( p=0.01 ) . At 60 min , the increase in Pao2/Fio2 ratio , to 172+/-76 , was no longer significant ( p=0.1 ) . There were no important changes in the levels of any of the measured cytokines at 5 min or 60 min following RM as compared with the baseline levels . CONCLUSIONS The results of our study demonstrate that recruitment maneuvers are well tolerated in patients with ARDS . Our data suggest no major hemodynamic or immunologic evidence of deterioration within the first hour of RM . In particular , cytokines , previously related to worsening lung injury and distal organ failure in patients with ARDS , are not elevated by use of an RM . Registered at : www . clinical trials.gov as NCT00127491 Interventions aim ed at recruiting the lung of patients with acute respiratory distress syndrome ( ARDS ) are not uniformly effective . Because the prone position increases homogeneity of inflation of the lung , we reasoned that it might enhance its potential for recruitment . We ventilated 10 patients with early ARDS ( PaO2/FIO2 , 121 + /- 46 mm Hg ; positive end-expiratory pressure , 14 + /- 3 cm H2O ) in supine and prone , with and without the addition of three consecutive " sighs " per minute to recruit the lung . Inspired oxygen fraction , positive end-expiratory pressure , and minute ventilation were kept constant . Sighs increased PaO2 in both supine and prone ( p < 0.01 ) . The highest values of PaO2 ( 192 + /- 41 mm Hg ) and end-expiratory lung volume ( 1840 + /- 790 ml ) occurred with the addition of sighs in prone and remained significantly elevated 1 hour after discontinuation of the sighs . The increase in PaO2 associated with the sighs , both in supine and prone , correlated linearly with the respective increase of end-expiratory lung volume ( r = 0.82 , p < 0.001 ) . We conclude that adding a recruitment maneuver such as cyclical sighs during ventilation in the prone position may provide optimal lung recruitment in the early stage of ARDS Objective To evaluate effects of lung recruitment maneuvers on gastric mucosal perfusion , systemic circulation , and lung mechanics in patients with acute lung injury . Design Prospect i ve observational clinical study . Setting General intensive care unit of university hospital . Patients and participants Fourteen patients with acute lung injury ( ten in the main study group and four in a validation group ) . Interventions Three 2-min-long recruitment maneuvers ( RM ) with transient increases in mean airway pressure to 35 cmH2O ( RM1 and RM2 ) and 44 cmH2O ( RM3 ) . Measurements and results Measurements of systemic hemodynamics , gastric mucosal perfusion ( laser Doppler flowmetry ) , and lung mechanics were performed immediately before , at the end of , and 3 min after each RM . Cardiac index decreased during all RMs while mean arterial pressure decreased only during RM3 . Gastric mucosal perfusion was not significantly changed during any of the RMs . When comparing values obtained before the first RM with values after the third RM there was a significant decrease in cardiac index ( P=0.043 ) and a non-significant ( P=0.051 ) decrease in gastric mucosal perfusion . There were no significant changes in systemic oxygenation or lung mechanics after three RMs , even though four patients showed marked transient increases in systemic oxygenation during RMs . Conclusions In this study of ten patients there were no significant changes in gastric mucosal perfusion during lung recruitment maneuvers . There was , however , a trend towards gradual decreases in gastric mucosal perfusion 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 ( defined as a ratio of partial pressure of arterial oxygen to fraction of inspired oxygen ) ( P<0.001 ) and respiratory-system compliance ( P=0.002 ) , higher levels of dead space ( P=0.002 ) , and higher rates of death ( P=0.02 ) than patients 
    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 assess how the level of positive end-expiratory pressure ( PEEP ) ( antiderecruitment strategy ) , etiological category of diffuse lung injury , and body position of the patient modify the effect of the alveolar recruitment maneuver ( ARM ) in acute respiratory distress syndrome ( ARDS ) . Design Prospect i ve clinical trial . Setting Medical intensive care unit at a tertiary hospital . Patients Forty-seven patients with early ARDS , including 19 patients from our preliminary study . InterventionFrom baseline ventilation at a tidal volume of 8 mL/kg and PEEP of 10 cm H2O , the ARM ( a stepwise increase in the level of PEEP up to 30 cm H2O with a concomitant decrease in the magnitude of tidal volume down to 2 mL/kg ) was given with ( ARM + PEEP , n = 20 ) or without ( ARM only , n = 19 ) subsequent increase of PEEP to 15 cm H2O . In eight other patients , PEEP was increased to 15 cm H2O without a preceding ARM ( PEEP only ) . Measurements and Results In all three groups , Pao2 was increased by the respective intervention ( all p < .05 ) . In the ARM-only group , Pao2 at 15 mins after intervention was lower than Pao2 immediate after intervention ( p = .046 ) . In the ARM + PEEP group , no such decrease in Pao2 was observed , and Pao2 at 15 , 30 , 45 , and 60 mins after intervention was higher than in the ARM-only group ( all p < .05 ) . Compared with the PEEP-only group , Pao2 of the ARM + PEEP group was higher immediately after intervention and at the later time points ( all p < .05 ) . Compared with patients with ARDS associated with direct lung injury ( pulmonary ARDS ) , patients with ARDS associated with indirect lung injury ( extrapulmonary ARDS ) showed a greater increase in Pao2 ( 27 ± 21 % vs. 130 ± 112%;p = .002 ) and a greater decrease in radiologic scores ( 1.0 ± 2.4 vs. 3.4 ± 1.5;p = .005 ) after the ARM . The increase in Pao2 induced by the ARM was greater for patients in the supine position than for patients in the prone position ( 61 ± 82 % vs. 21 ± 14%;p = .028 ) . Consequently , Pao2 immediately after the ARM was similar in the two groups of patients in different positions . Conclusions After the ARM , a sufficient level of PEEP is required as an antiderecruitment strategy . Pulmonary ARDS and extrapulmonary ARDS may be different pathophysiologic entities . An effective ARM may obviate the need for the prone position in ARDS at least in terms of oxygenation Objective To assess the acute effect of a lung recruitment maneuver ( LRM ) on lung morphology in patients with acute lung injury ( ALI ) or acute respiratory distress syndrome ( ARDS ) . Patients Ten patients with ALI/ARDS on mechanical ventilation . Design Prospect i ve clinical study . Setting Computed tomography ( CT ) scan facility in a teaching hospital . Interventions An LRM performed by stepwise increases in positive end-expiratory pressure ( PEEP ) of up to 30–40 cmH2O . Lung basal CT sections were taken at end-expiration ( patients 1 to 5 ) , and at end-expiration and end-inspiration ( patients 6 to10 ) . Arterial blood gases and static compliance ( Cst ) were measured before , during and after the LRM . Measurements and main results Poorly aerated and non-aerated tissue at PEEP 10 cmH2O accounted for 60.0±29.1 % of lung parenchyma , while only 1.1±1.8 % was hyperinflated . Increasing PEEP to 20 and 30 cmH2O , compared to PEEP 10 cmH2O , decreased poorly aerated and non-aerated tissue by 16.2±28.0 % and 33.4±13.8 % , respectively ( p<0.05 ) . This was associated with an increase in PaO2 and a decrease in total static compliance . Inspiration increased alveolar recruitment at all PEEP levels . Hyperinflated tissue increased up to 2.9±4.0 % with PEEP 30 cmH2O , and to a lesser degree with inspiration . No barotrauma or severe hypotension occurred . Conclusions Lung recruitment maneuvers improve oxygenation by exp and ing collapsed alveoli without inducing too much hyperinflation in ALI/ARDS patients .  An LRM during the CT scan gives morphologic and functional information that could be useful in setting ventilatory parameters 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 BACKGROUND There are reports of rigors and /or clinical deterioration following recruitment maneuvers ( RMs ) , leading us to question whether the use of sustained high-pressure inflation could lead to release of inflammatory mediators . METHODS Prospect i ve cohort study of 26 patients with ARDS receiving mechanical ventilation . A single RM was performed during which the mean airway pressure was increased to 40 cm H2O and held constant for a period of 30 s. The concentration of nine cytokines ( interleukin [IL]-1 , IL-6 , IL-8 , IL-10 , tumor necrosis factor [TNF]-alpha , Fas lig and , vascular endothelial growth factor , TNF receptor 1 , TNF receptor 2 ) was measured longitudinally at three time points : prior to initiation of the RM , 5 min after the RM , and 60 min after the RM . RESULTS RMs were tolerated well from a hemodynamic perspective . Oxygenation improved as reflected by an increased Pao2/fraction of inspired oxygen ( Fio2 ) ratio from 140+/-49 at baseline to 190+/-78 ( mean+/-SD ) at 5 min after the RM ( p=0.01 ) . At 60 min , the increase in Pao2/Fio2 ratio , to 172+/-76 , was no longer significant ( p=0.1 ) . There were no important changes in the levels of any of the measured cytokines at 5 min or 60 min following RM as compared with the baseline levels . CONCLUSIONS The results of our study demonstrate that recruitment maneuvers are well tolerated in patients with ARDS . Our data suggest no major hemodynamic or immunologic evidence of deterioration within the first hour of RM . In particular , cytokines , previously related to worsening lung injury and distal organ failure in patients with ARDS , are not elevated by use of an RM . Registered at : www . clinical trials.gov as NCT00127491 Interventions aim ed at recruiting the lung of patients with acute respiratory distress syndrome ( ARDS ) are not uniformly effective . Because the prone position increases homogeneity of inflation of the lung , we reasoned that it might enhance its potential for recruitment . We ventilated 10 patients with early ARDS ( PaO2/FIO2 , 121 + /- 46 mm Hg ; positive end-expiratory pressure , 14 + /- 3 cm H2O ) in supine and prone , with and without the addition of three consecutive " sighs " per minute to recruit the lung . Inspired oxygen fraction , positive end-expiratory pressure , and minute ventilation were kept constant . Sighs increased PaO2 in both supine and prone ( p < 0.01 ) . The highest values of PaO2 ( 192 + /- 41 mm Hg ) and end-expiratory lung volume ( 1840 + /- 790 ml ) occurred with the addition of sighs in prone and remained significantly elevated 1 hour after discontinuation of the sighs . The increase in PaO2 associated with the sighs , both in supine and prone , correlated linearly with the respective increase of end-expiratory lung volume ( r = 0.82 , p < 0.001 ) . We conclude that adding a recruitment maneuver such as cyclical sighs during ventilation in the prone position may provide optimal lung recruitment in the early stage of ARDS Objective To evaluate effects of lung recruitment maneuvers on gastric mucosal perfusion , systemic circulation , and lung mechanics in patients with acute lung injury . Design Prospect i ve observational clinical study . Setting General intensive care unit of university hospital . Patients and participants Fourteen patients with acute lung injury ( ten in the main study group and four in a validation group ) . Interventions Three 2-min-long recruitment maneuvers ( RM ) with transient increases in mean airway pressure to 35 cmH2O ( RM1 and RM2 ) and 44 cmH2O ( RM3 ) . Measurements and results Measurements of systemic hemodynamics , gastric mucosal perfusion ( laser Doppler flowmetry ) , and lung mechanics were performed immediately before , at the end of , and 3 min after each RM . Cardiac index decreased during all RMs while mean arterial pressure decreased only during RM3 . Gastric mucosal perfusion was not significantly changed during any of the RMs . When comparing values obtained before the first RM with values after the third RM there was a significant decrease in cardiac index ( P=0.043 ) and a non-significant ( P=0.051 ) decrease in gastric mucosal perfusion . There were no significant changes in systemic oxygenation or lung mechanics after three RMs , even though four patients showed marked transient increases in systemic oxygenation during RMs . Conclusions In this study of ten patients there were no significant changes in gastric mucosal perfusion during lung recruitment maneuvers . There was , however , a trend towards gradual decreases in gastric mucosal perfusion 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 ( defined as a ratio of partial pressure of arterial oxygen to fraction of inspired oxygen ) ( P<0.001 ) and respiratory-system compliance ( P=0.002 ) , higher levels of dead space ( P=0.002 ) , and higher rates of death ( P=0.02 ) than patients 
    Output:
    