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 : The available predictors of spontaneous-breathing-trial ( SBT ) success/failure lack accuracy . We devised a new index , the CORE index ( compliance , oxygenation , respiration , and effort ) . OBJECTIVE : To compare the CORE index to the CROP index ( compliance , rate , oxygenation , and pressure ) , airway-occlusion pressure  0.1 s after the start of inspiratory flow ( P0.1 ) , and rapid shallow breathing index ( RSBI ) for predicting SBT success/failure in a critical care environment . METHODS : With 47 mechanically ventilated patients recovering from respiratory failure , of various causes , we prospect ively examined the SBT success/failure prediction accuracy and calculated receiver operating characteristic curves , sensitivity , specificity , and likelihood ratios of CORE , CROP , P0.1 , and RSBI . RESULTS : The specificities were CORE 0.95 , P0.1 0.70 , CROP 0.70 , and RSBI 0.65 . The sensitivities were CORE 1.00 , CROP 1.00 , P0.1 0.93 , and RSBI 0.89 . The areas under the receiver operating characteristic curve were CORE 1.00 ( 95 % CI 0.92–1.00 ) , CROP 0.91 ( 95 % CI 0.79–0.97 ) , P0.1 0.81 ( 95 % CI 0.67–0.91 ) , and RSBI 0.77 ( 95 % CI 0.62–0.88 ) . The positive likelihood ratios were CORE 20.0 , CROP 3.3 , P0.1 3.1 , and RSBI 2.5 . The negative likelihood ratios were CORE 0.0 , CROP 0.0 , P0.1 0.1 , and RSBI 0.2 . CONCLUSIONS : The CORE index was the most accurate predictor of SBT success/failure 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 This study aim ed to examine the clinical characteristics , weaning pattern , and outcome of patients requiring prolonged mechanical ventilation in acute intensive care unit setting s in a re source -limited country . Methods This was a prospect i ve single-center observational study in India , where all adult patients requiring prolonged ventilation  were followed for weaning duration and pattern and for survival at both intensive care unit discharge and at 12 months . The definition of prolonged mechanical ventilation used was that of the National Association for Medical Direction of Respiratory Care . Results During the one-year period , 49 patients with a mean age of 49.7 years had prolonged ventilation ; 63 % were male , and 84 % had a medical illness . The median APACHE II and SOFA scores on admission were 17 and 9 , respectively . The median number of ventilation days was 37 . The most common reason for starting ventilation was respiratory failure secondary to sepsis ( 67 % ) . Weaning was initiated in 39 ( 79.5 % ) patients , with success in 34 ( 87 % ) . The median weaning duration was 14 ( 9.5 - 19 ) days , and the median length of intensive care unit stay was 39 ( 32 - 58.5 ) days . Duration of vasopressor support and need for hemodialysis were significant independent predictors of unsuccessful ventilator liberation . At the 12-month follow-up , 65 % had survived . Conclusion In acute intensive care units , more than one-fourth of patients with invasive ventilation required prolonged ventilation . Successful weaning was achieved in two-thirds of patients , and most survived at the 12-month follow-up Introduction The purpose of this study was to evaluate if ultrasound derived measures of diaphragm thickening , rather than diaphragm motion , can be used to predict extubation success or failure . Methods Sixty-three mechanically ventilated patients were prospect ively recruited .  Diaphragm thickness ( tdi ) was measured in the zone of apposition of the diaphragm to the rib cage using a 7–10 MHz ultrasound transducer . The percent change in tdi between end-expiration and end-inspiration ( Δtdi% ) was calculated during either spontaneous breathing ( SB ) or pressure support ( PS ) weaning trials . A successful extubation was defined as SB for > 48 h following endotracheal tube removal . Results Of the 63 subjects studied , 27 patients were weaned with SB and 36 were weaned with PS . The combined sensitivity and specificity of Δtdi%≥30 % for extubation success was 88 % and 71 % , respectively . The positive predictive value and negative predictive value were 91 % and 63 % , respectively . The area under the receiver operating characteristic curve was 0.79 for Δtdi% . Conclusions Ultrasound measures of diaphragm thickening in the zone of apposition may be useful to predict extubation success or failure during SB or PS trials BACKGROUND Predictor indexes are often included in weaning protocol s and may help the intensive care unit ( ICU ) staff to reach expected weaning outcome in patients on mechanical ventilation . OBJECTIVE The objective of this study is to evaluate the potential of weaning predictors during extubation . DESIGN This is a prospect i ve clinical study . SETTING S The study was conducted in 3 medical-surgical ICUs . PATIENTS Five hundred consecutive unselected patients ventilated for more than 48 hours were included . METHODS AND MEASUREMENTS All patients were extubated after 30 minutes of successful spontaneous breathing trial and followed up for 48 hours . The protocol evaluated hemodynamics , ventilation parameters , arterial blood gases , and the weaning indexes frequency to tidal volume ratio ; compliance , respiratory rate , oxygenation , and pressure ; maximal inspiratory pressure ; maximal expiratory pressure ; Pao(2)/fraction of inspired oxygen ; respiratory frequency ; and tidal volume during mechanical ventilation  and in the 1st and 30th minute of spontaneous breathing trial . RESULTS Reintubation rate was 22.8 % , and intensive care mortality was higher in the reintubation group ( 10 % vs 31 % ; P < .0001 ) . The areas under the receiver operating characteristic curve showed that tests did not discriminate which patients could tolerate extubation . CONCLUSION Usual weaning indexes are poor predictors for extubation outcome in the overall ICU population INTRODUCTION : The extubation period is one of the most challenging aspects for intensive care teams . Timely recognition of the return to spontaneous ventilation is essential for reducing costs , morbidity , and mortality . Several weaning predictors were studied in an attempt to evaluate the outcome of removing ventilatory support . The purpose of this study was to analyze the predictive performance of the modified integrative weaning index ( IWI ) in the extubation process . METHODS : A prospect i ve study was performed in an ICU in a public hospital in Porto Alegre , Brazil , with 59 adult medical-surgical beds . The final population of the study comprised 153 patients receiving mechanical ventilation for over 48 h who were extubated during the period from February to November 2011 . Demographic data and clinical parameters were collected in addition to extubation predictors , including static compliance of the respiratory system , ratio of breathing frequency to tidal volume , tracheal airway-occlusion pressure 0.1 s after the start of inspiratory flow , and modified IWI . RESULTS : Extubation failure was observed in 23 of the subjects ( 15 % ) . Subjects with greater positive fluid balance , lower hemoglobin levels , and lower levels of bicarbonate presented a higher rate of reintubation . The 3 modified IWI values ( the first and 30th minute of the spontaneous breathing trial and the difference between them ) , as well as the other ventilatory parameters and extubation predictors , displayed poor extubation outcome discrimination accuracy . All indexes presented small areas under the receiver operating characteristic curve , and no accurate cutoff point was identified . CONCLUSIONS : We concluded that modified IWI , similar to other extubation predictors , does not accurately predict extubation failure BACKGROUND The need for reintubation after extubation and discontinuation of mechanical ventilation is not uncommon and is associated with increased mortality . Noninvasive positive-pressure ventilation has been suggested as a promising therapy for patients with respiratory failure after extubation , but a single-center , r and omized trial recently found no benefit . We conducted a multicenter , r and omized trial to evaluate the effect of noninvasive positive-pressure ventilation on mortality in this clinical setting . METHODS Patients in 37 centers in eight countries who were electively extubated after at least 48 hours of mechanical ventilation and who had respiratory failure within the subsequent 48 hours were r and omly assigned to either noninvasive positive-pressure ventilation by face mask or st and ard medical therapy . RESULTS A total of 221 patients with similar baseline characteristics had been r and omly assigned to either noninvasive ventilation ( 114 patients ) or st and ard medical therapy ( 107 patients ) when the trial was stopped early , after an interim analysis . There was no difference between the noninvasive-ventilation group and the st and ard-therapy group in the need for reintubation ( rate of reintubation , 48 percent in both groups ; relative risk in the noninvasive-ventilation group , 0.99 ; 95 percent confidence interval , 0.76 to 1.30 ) . The rate of death in the intensive care unit was higher in the noninvasive-ventilation group than in the st and ard-therapy group ( 25 percent vs. 14 percent ; relative risk , 1.78 ; 95 percent confidence interval , 1.03 to 3.20 ; P=0.048 ) , and the median time from respiratory failure to reintubation was longer in the noninvasive-ventilation group ( 12 hours vs. 2 hours 30 minutes , P=0.02 ) . CONCLUSIONS Noninvasive positive-pressure ventilation does not prevent the need for reintubation or reduce mortality in unselected patients who have respiratory failure after extubation We have previously shown ( Am . J. Respir . Crit . Care Med . 1995;152:1248 - 1255 ) that in patients needing mechanical ventilation  , the load imposed on the inspiratory muscles is excessive relative to their neuromuscular capacity . We have therefore hypothesized that weaning failure may occur because at the time of the trial of spontaneous breathing there is insufficient reduction of the inspiratory load . We therefore prospect ively studied patients who initially had failed to wean from mechanical ventilation ( F ) but had successful weaning ( S ) on a later occasion . Compared with S , during F patients had greater intrinsic positive end-expiratory pressure ( 6 . 10 + /- 2.45 versus 3.83 + /- 2.69 cm H2O ) , dynamic hyperinflation ( 327 + /- 180 versus 213 + /- 175 ml ) , total resistance ( Rmax , 14.14 + /- 4.95 versus 11.19 + /- 4.01 cm H2O/L/s ) , ratio of mean to maximum inspiratory pressure ( 0.46 + /- 0.1 versus 0.31 + /- 0.08 ) , tension time index ( TTI , 0.162 + /- 0.032 versus 0.102 + /- 0.023 ) and power ( 315 + /- 153 versus 215 + /- 75 cm H2O x L/min ) , less maximum inspiratory pressure ( 42.3 + /- 12.7 versus 53.8 + /- 15.1 cm H2O ) , and a breath 
    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 : The available predictors of spontaneous-breathing-trial ( SBT ) success/failure lack accuracy . We devised a new index , the CORE index ( compliance , oxygenation , respiration , and effort ) . OBJECTIVE : To compare the CORE index to the CROP index ( compliance , rate , oxygenation , and pressure ) , airway-occlusion pressure  0.1 s after the start of inspiratory flow ( P0.1 ) , and rapid shallow breathing index ( RSBI ) for predicting SBT success/failure in a critical care environment . METHODS : With 47 mechanically ventilated patients recovering from respiratory failure , of various causes , we prospect ively examined the SBT success/failure prediction accuracy and calculated receiver operating characteristic curves , sensitivity , specificity , and likelihood ratios of CORE , CROP , P0.1 , and RSBI . RESULTS : The specificities were CORE 0.95 , P0.1 0.70 , CROP 0.70 , and RSBI 0.65 . The sensitivities were CORE 1.00 , CROP 1.00 , P0.1 0.93 , and RSBI 0.89 . The areas under the receiver operating characteristic curve were CORE 1.00 ( 95 % CI 0.92–1.00 ) , CROP 0.91 ( 95 % CI 0.79–0.97 ) , P0.1 0.81 ( 95 % CI 0.67–0.91 ) , and RSBI 0.77 ( 95 % CI 0.62–0.88 ) . The positive likelihood ratios were CORE 20.0 , CROP 3.3 , P0.1 3.1 , and RSBI 2.5 . The negative likelihood ratios were CORE 0.0 , CROP 0.0 , P0.1 0.1 , and RSBI 0.2 . CONCLUSIONS : The CORE index was the most accurate predictor of SBT success/failure 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 This study aim ed to examine the clinical characteristics , weaning pattern , and outcome of patients requiring prolonged mechanical ventilation in acute intensive care unit setting s in a re source -limited country . Methods This was a prospect i ve single-center observational study in India , where all adult patients requiring prolonged ventilation  were followed for weaning duration and pattern and for survival at both intensive care unit discharge and at 12 months . The definition of prolonged mechanical ventilation used was that of the National Association for Medical Direction of Respiratory Care . Results During the one-year period , 49 patients with a mean age of 49.7 years had prolonged ventilation ; 63 % were male , and 84 % had a medical illness . The median APACHE II and SOFA scores on admission were 17 and 9 , respectively . The median number of ventilation days was 37 . The most common reason for starting ventilation was respiratory failure secondary to sepsis ( 67 % ) . Weaning was initiated in 39 ( 79.5 % ) patients , with success in 34 ( 87 % ) . The median weaning duration was 14 ( 9.5 - 19 ) days , and the median length of intensive care unit stay was 39 ( 32 - 58.5 ) days . Duration of vasopressor support and need for hemodialysis were significant independent predictors of unsuccessful ventilator liberation . At the 12-month follow-up , 65 % had survived . Conclusion In acute intensive care units , more than one-fourth of patients with invasive ventilation required prolonged ventilation . Successful weaning was achieved in two-thirds of patients , and most survived at the 12-month follow-up Introduction The purpose of this study was to evaluate if ultrasound derived measures of diaphragm thickening , rather than diaphragm motion , can be used to predict extubation success or failure . Methods Sixty-three mechanically ventilated patients were prospect ively recruited .  Diaphragm thickness ( tdi ) was measured in the zone of apposition of the diaphragm to the rib cage using a 7–10 MHz ultrasound transducer . The percent change in tdi between end-expiration and end-inspiration ( Δtdi% ) was calculated during either spontaneous breathing ( SB ) or pressure support ( PS ) weaning trials . A successful extubation was defined as SB for > 48 h following endotracheal tube removal . Results Of the 63 subjects studied , 27 patients were weaned with SB and 36 were weaned with PS . The combined sensitivity and specificity of Δtdi%≥30 % for extubation success was 88 % and 71 % , respectively . The positive predictive value and negative predictive value were 91 % and 63 % , respectively . The area under the receiver operating characteristic curve was 0.79 for Δtdi% . Conclusions Ultrasound measures of diaphragm thickening in the zone of apposition may be useful to predict extubation success or failure during SB or PS trials BACKGROUND Predictor indexes are often included in weaning protocol s and may help the intensive care unit ( ICU ) staff to reach expected weaning outcome in patients on mechanical ventilation . OBJECTIVE The objective of this study is to evaluate the potential of weaning predictors during extubation . DESIGN This is a prospect i ve clinical study . SETTING S The study was conducted in 3 medical-surgical ICUs . PATIENTS Five hundred consecutive unselected patients ventilated for more than 48 hours were included . METHODS AND MEASUREMENTS All patients were extubated after 30 minutes of successful spontaneous breathing trial and followed up for 48 hours . The protocol evaluated hemodynamics , ventilation parameters , arterial blood gases , and the weaning indexes frequency to tidal volume ratio ; compliance , respiratory rate , oxygenation , and pressure ; maximal inspiratory pressure ; maximal expiratory pressure ; Pao(2)/fraction of inspired oxygen ; respiratory frequency ; and tidal volume during mechanical ventilation  and in the 1st and 30th minute of spontaneous breathing trial . RESULTS Reintubation rate was 22.8 % , and intensive care mortality was higher in the reintubation group ( 10 % vs 31 % ; P < .0001 ) . The areas under the receiver operating characteristic curve showed that tests did not discriminate which patients could tolerate extubation . CONCLUSION Usual weaning indexes are poor predictors for extubation outcome in the overall ICU population INTRODUCTION : The extubation period is one of the most challenging aspects for intensive care teams . Timely recognition of the return to spontaneous ventilation is essential for reducing costs , morbidity , and mortality . Several weaning predictors were studied in an attempt to evaluate the outcome of removing ventilatory support . The purpose of this study was to analyze the predictive performance of the modified integrative weaning index ( IWI ) in the extubation process . METHODS : A prospect i ve study was performed in an ICU in a public hospital in Porto Alegre , Brazil , with 59 adult medical-surgical beds . The final population of the study comprised 153 patients receiving mechanical ventilation for over 48 h who were extubated during the period from February to November 2011 . Demographic data and clinical parameters were collected in addition to extubation predictors , including static compliance of the respiratory system , ratio of breathing frequency to tidal volume , tracheal airway-occlusion pressure 0.1 s after the start of inspiratory flow , and modified IWI . RESULTS : Extubation failure was observed in 23 of the subjects ( 15 % ) . Subjects with greater positive fluid balance , lower hemoglobin levels , and lower levels of bicarbonate presented a higher rate of reintubation . The 3 modified IWI values ( the first and 30th minute of the spontaneous breathing trial and the difference between them ) , as well as the other ventilatory parameters and extubation predictors , displayed poor extubation outcome discrimination accuracy . All indexes presented small areas under the receiver operating characteristic curve , and no accurate cutoff point was identified . CONCLUSIONS : We concluded that modified IWI , similar to other extubation predictors , does not accurately predict extubation failure BACKGROUND The need for reintubation after extubation and discontinuation of mechanical ventilation is not uncommon and is associated with increased mortality . Noninvasive positive-pressure ventilation has been suggested as a promising therapy for patients with respiratory failure after extubation , but a single-center , r and omized trial recently found no benefit . We conducted a multicenter , r and omized trial to evaluate the effect of noninvasive positive-pressure ventilation on mortality in this clinical setting . METHODS Patients in 37 centers in eight countries who were electively extubated after at least 48 hours of mechanical ventilation and who had respiratory failure within the subsequent 48 hours were r and omly assigned to either noninvasive positive-pressure ventilation by face mask or st and ard medical therapy . RESULTS A total of 221 patients with similar baseline characteristics had been r and omly assigned to either noninvasive ventilation ( 114 patients ) or st and ard medical therapy ( 107 patients ) when the trial was stopped early , after an interim analysis . There was no difference between the noninvasive-ventilation group and the st and ard-therapy group in the need for reintubation ( rate of reintubation , 48 percent in both groups ; relative risk in the noninvasive-ventilation group , 0.99 ; 95 percent confidence interval , 0.76 to 1.30 ) . The rate of death in the intensive care unit was higher in the noninvasive-ventilation group than in the st and ard-therapy group ( 25 percent vs. 14 percent ; relative risk , 1.78 ; 95 percent confidence interval , 1.03 to 3.20 ; P=0.048 ) , and the median time from respiratory failure to reintubation was longer in the noninvasive-ventilation group ( 12 hours vs. 2 hours 30 minutes , P=0.02 ) . CONCLUSIONS Noninvasive positive-pressure ventilation does not prevent the need for reintubation or reduce mortality in unselected patients who have respiratory failure after extubation We have previously shown ( Am . J. Respir . Crit . Care Med . 1995;152:1248 - 1255 ) that in patients needing mechanical ventilation  , the load imposed on the inspiratory muscles is excessive relative to their neuromuscular capacity . We have therefore hypothesized that weaning failure may occur because at the time of the trial of spontaneous breathing there is insufficient reduction of the inspiratory load . We therefore prospect ively studied patients who initially had failed to wean from mechanical ventilation ( F ) but had successful weaning ( S ) on a later occasion . Compared with S , during F patients had greater intrinsic positive end-expiratory pressure ( 6 . 10 + /- 2.45 versus 3.83 + /- 2.69 cm H2O ) , dynamic hyperinflation ( 327 + /- 180 versus 213 + /- 175 ml ) , total resistance ( Rmax , 14.14 + /- 4.95 versus 11.19 + /- 4.01 cm H2O/L/s ) , ratio of mean to maximum inspiratory pressure ( 0.46 + /- 0.1 versus 0.31 + /- 0.08 ) , tension time index ( TTI , 0.162 + /- 0.032 versus 0.102 + /- 0.023 ) and power ( 315 + /- 153 versus 215 + /- 75 cm H2O x L/min ) , less maximum inspiratory pressure ( 42.3 + /- 12.7 versus 53.8 + /- 15.1 cm H2O ) , and a breath 
    Output:
    