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 compare the effect of high-frequency ventilation versus other ventilation methods applied during cardiopulmonary bypass on postbypass oxygenation . DESIGN Prospect i ve , r and omized study . SETTING University hospital . PARTICIPANTS Seventy-five patients undergoing coronary artery bypass graft surgery . INTERVENTIONS Patients were allocated to 5 equal groups of different ventilation methods during bypass . Groups 1 and 2 received high-frequency , low-volume ventilation with 100 % and 21 % oxygen , respectively . Groups 3 and 4 received 5 cm H(2)O of continuous positive airway pressure ( CPAP ) with either 100 % or 21 % oxygen . Patients from group 5 were disconnected from the ventilator during the bypass period . MEASUREMENTS AND MAIN RESULTS Spirometry data , blood gas analysis , oxygen saturation as measured by pulse oximetry , and end-tidal carbon dioxide were recorded 5 minutes before chest opening , 5 minutes before bypass , 5 minutes after bypass , 5 minutes after chest closure and 6 , 12 , 18 , and 24 hours after surgery . There were no differences in compliance and mean airway pressures . Alveolar-to-arterial oxygen gradients increased , and PaO(2 ) decreased significantly ( p < 0.05 ) in all groups 5 minutes after bypass and this trend continued in the postoperative period . Patients from group 3 had higher PaO(2 ) and lower alveolar-to-arterial oxygen gradients , 5 minutes after weaning from bypass ( p < 0.05 ) . Extubation times were similar in all groups . CONCLUSIONS The alveolar-arterial oxygen gradient was lower , and the PaO(2 ) was higher 5 minutes after bypass in patients receiving CPAP ( 100 % O(2 ) ) as compared with those ventilated with high-frequency ventilation Pulmonary dysfunction with impairment of lung function and oxygenation is one of the most serious problems in the early postoperative period after cardiac surgery . In this study we investigated the effect of alveolar recruitment strategy during cardiopulmonary bypass on postoperative gas exchange and lung function . This prospect i ve r and omized study included 32 patients undergoing elective myocardial revascularization with cardiopulmonary bypass .  In 16 patients 5 cm H2O of positive end-expiratory pressure was applied after intubation and maintained until extubation ( Group I ) . In the other 16 patients ( group II ) a positive end expiratory pressure ( PEEP ) of 5 cm H2O was maintained as well but was increased to 14 cm H2O every 20 min for 2 min during cross clamp . Measurements were taken preoperatively , before skin incision , before and after ( 3 , 24 , 48 h ) cardiopulmonary bypass and before discharge ( 6th postoperative day ) . Postoperative gas exchange , extravascular lung water and lung function showed no significant difference between the groups . Postoperative pulmonary function variables were lower in both groups compared to baseline values . In patients with normal preoperative pulmonary function , application of an alveolar recruitment strategy during cardiopulmonary bypass does not improve postoperative gas exchange and lung function after cardiac surgery OBJECTIVE Pulmonary atelectasis and hypoxemia remain considerable problems after cardiac surgery . The objective of this study was to determine the efficacy of consecutive vital capacity maneuvers ( C-VCMs ) to improve oxygenation in patients after cardiac surgery . STUDY DESIGN R and omized , controlled clinical trial . SETTING Tertiary referral teaching center . PARTICIPANTS Ninety-five patients requiring elective cardiac surgery with cardiopulmonary bypass ( CPB ) .  INTERVENTION Patients were r and omly allocated to either C-VCM or control groups . In the C-VCM group , lung inflation at pressure of 35 cmH(2)O was sustained for 15 seconds before separation from CPB and at 30 cmH(2)O for 5 seconds after admission to the intensive care unit ( ICU ) . MEASUREMENTS AND MAIN RESULTS The primary outcome was the ratio of arterial oxygen tension to inspired oxygen fraction measured at the following predetermined time intervals : after induction of anesthesia , 15 minutes after separation from CPB , after admission to the ICU , after 3 hours of positive-pressure ventilation , after extubation , and before ICU discharge . C-VCM result ed in better arterial oxygenation extending from the immediate postoperative period to approximately 24 hours after surgery at the time of ICU discharge . There were no significant adverse events related to C-VCM application . CONCLUSION C-VCM is an effective method to reduce hypoxemia associated with the formation of atelectasis after cardiac surgery with CPB BACKGROUND : The aim of our study was to evaluate the pulmonary effects of noninvasive ventilation ( NIV ) with or without recruitment maneuver ( RM ) after open heart surgery . METHODS : One-hundred patients undergoing coronary artery bypass surgery were r and omized into four groups after the operation : 1 ) RM with sustained inflation during mechanical ventilation postoperatively ( RM group , n = 25 ) ; 2 ) RM combined with NIV applied for 1/2-h periods every 6 h in the first postoperative day after tracheal extubation ( RM-NIV group , n = 25 ) ; 3 ) NIV after tracheal extubation ( NIV group , n = 25 ) ; and 4 ) a control group consisting of patients receiving neither RM nor NIV ( control group , n = 25 ) . Pulmonary function tests , oxygenation index , and atelectasis on chest radiograph were evaluated and compared among the groups . RESULTS : RM provided higher arterial oxygen levels during mechanical ventilation and after tracheal extubation compared to other interventions . Oxygenation was better in the RM-NIV and NIV groups than in the control group ( P = 0.02 and P = 0.008 , respectively ) at the end of the study . The postoperative atelectasis score of the control group ( median : 1 ) was higher than those of the RM ( 1 ; P = 0.03 ) , RM-NIV ( 0 ; P < 0.01 ) and NIV ( 0 ; P < 0.01 ) groups . Pulmonary function of the NIV groups on postoperative day 2 was better than in the other groups , whereas the tests were similar among the groups on postoperative day 7 . CONCLUSIONS : NIV associated with RM provided better oxygenation both during and after the mechanical ventilation period . NIV either alone or in combination with RM provided lower atelectasis scores and better early pulmonary function tests compared to the control group , without a significant difference regarding the duration of mechanical ventilation , intensive care unit stay , and the length of hospitalization .  NIV combined with RM is recommended after open heart surgery to prevent postoperative atelectasis and hypoxemia BACKGROUND Pulmonary dysfunction is one of the most common manifestations of inflammatory response after cardiopulmonary bypass ( CPB ) . OBJECTIVE This prospect i ve r and omized study was conducted to evaluate the effect of a modified ultrafiltration ( MUF ) technique on pulmonary function after CPB in children . METHODS Forty patients weighing from 5 to 10 kg with congenital heart disease who required CPB for primary biventricular operative repair were prospect ively r and omized into two groups . The control group received conventional ultrafiltration ( CUF ) during CPB , and the study group received CUF and MUF .  Pulmonary compliance ( static and dynamic ) and gas exchange capacity of the lung expressed as oxygen index , respiratory index , ventilation index , and alveolar-arterial oxygen pressure difference were measured after intubation ( baseline ) , at the termination of CPB , at the end of MUF , on admission to the ICU , and 6 h postoperatively . RESULTS There was no significant difference in lung compliance and gas exchange between the two groups before CPB . CPB produced a significant decrease in static and dynamic lung compliance in both groups . In the control group , static and dynamic lung compliance decreased from 1.0 + /- 0.3 to 0.90 + /- 0.3 mL/cm/kg and 0.87 + /- 0.2 to 0.71 + /- 0.1 mL/cm/kg ( + /- SE ) [ p = 0.0002 and p = 0.002 , respectively ] . In the study group , static and dynamic lung compliance decreased from 1.0 + /- 0.2 to 0.89 + /- 0.03 mL/cm/kg and 0.94 + /- 0.2 to 0.77 + /- 0.1 mL/cm/kg ( p = 0.002 and p = 0.002 , respectively ) . There was no significant difference in the decrease in static ( p = 0.9 ) or dynamic lung compliance ( p = 0.3 ) between the two groups . MUF produced a significant immediate improvement in both static lung compliance ( 0.89 + /- 0.2 to 0.98 + /- 0.2 mL/cm/kg , p = 0.03 ) and dynamic lung compliance ( 0.77 + /- 0.1 to 0.93 + /- 0.2 mL/cm/kg , p = 0.007 ) . The same was observed regarding the gas exchange capacity . CPB produced a significant decrease in lung gas exchange capacity , and MUF produced a significant immediate improvement in lung gas exchange capacity . The effect of MUF on lung compliance and gas exchange capacity was not sustained after admission to the ICU nor 6 h later postoperatively . There was no significant difference in the time of extubation between the two groups ( 12 + /- 3 h and 13 + /- 2 h , p = 0.4 ) , the length of ICU stay , or the total hospital stay postoperatively . CONCLUSIONS The use of MUF after CPB can produce an immediate improvement in lung compliance and gas exchange capacity , which may effectively minimize pulmonary dysfunction postbiventricular repair of congenital heart disease . However , these improvements are not sustained for the first 6 h postoperatively and do not reduce the duration of postoperative intubation , ICU stay , or total hospital stay BACKGROUND : The aim of our study was to evaluate the pulmonary and hemodynamic effects of two different recruitment maneuvers after open heart surgery . METHODS : Sixty patients undergoing coronary artery bypass surgery  were r and omized into three groups after operation : recruitment maneuver with continuous positive airway pressure ( CPAP ) ( CPAP-40 group , n = 20 ) , recruitment by positive end-expiratory pressure ( PEEP ) ( PEEP-20 group , n = 20 ) , and 5 cm H2O PEEP ( PEEP-5 group , n = 20 ) . In the CPAP-40 group , 40 cm H2O peak inspiratory pressure was applied for 30 s , then PEEP was reduced to 20 cm H2O and ventilation was continued with baseline variables with PEEP decreased until the best Pao2 was achieved . In the PEEP-20 group , 20 cm H2O PEEP was set for 2 min , tidal volume was adjusted to achieve a peak inspiratory airway pressure of 40 cm H2O during the maneuver , then PEEP was decreased until the best Pao2 had been achieved . In the PEEP-5 group , 5 cm H2O PEEP was applied postoperatively . RESULTS : The mean arterial blood pressure of the CPAP-40 group was lower than that of the PEEP-20 ( P < 0.01 ) and PEEP-5 groups ( P < 0.01 ) during the interventions . Oxygenation was higher in both recruitment groups than in the PEEP-5 group during the mechanical ventilation period . There was no significant difference among the groups beyond that period . The atelectasis score of the PEEP-5 group ( 1.3 ± 0.9 ) on postoperative day 1 was higher than that of the CPAP-40 ( 0.65 ± 0.6 ; P = 0.01 ) and PEEP-20 ( 0.65 ± 0.5 ; P = 0.01 ) groups . CONCLUSIONS : The recruitment techniques with postmaneuver PEEP increased oxygenation and decreased atelectasis equally , whereas PEEP-20 provided more stable hemodynamic conditions than the CPAP maneuver In this study , 30 patients undergoing elective myocardial revascularization were divided r and omly in three groups ( 10 patients each ) with different management of the lungs during CPB : Group 1 , lungs deflated ; Group 2 , static inflation with PEEP = 5 cmH2O and FIO2 = 1.0 ; Group 3 , static inflation with PEEP = 5 cmH2O and FIO2 = 0.21 . Measurements ( Qs/Qt , P(A-a)O2 , PaO2 , Cstat , Cdyn , PIP , AUTO-PEEP , Rrs , max , Rrs , min and DRrs ) were performed after the induction of anesthesia ( T0 ) , 20 minutes ( T1 ) and 2 hours ( T2 ) after the end of CPB . Respiratory mechanics data were obtained only at T0 and T2 because the sternal retraction . The Group 1 presented a statistically significant increase in Qs/Qt , P(A-a)O2 and Peak Inspiratory Pressure ( PIP ) ; in this group we noticed also a decrease in PaO2 values , static compliance ( Cstat ) and dynamic compliance ( Cdyn ) values comparing basal versus T1 and T2 values . The Group 2 showed a 
    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 compare the effect of high-frequency ventilation versus other ventilation methods applied during cardiopulmonary bypass on postbypass oxygenation . DESIGN Prospect i ve , r and omized study . SETTING University hospital . PARTICIPANTS Seventy-five patients undergoing coronary artery bypass graft surgery . INTERVENTIONS Patients were allocated to 5 equal groups of different ventilation methods during bypass . Groups 1 and 2 received high-frequency , low-volume ventilation with 100 % and 21 % oxygen , respectively . Groups 3 and 4 received 5 cm H(2)O of continuous positive airway pressure ( CPAP ) with either 100 % or 21 % oxygen . Patients from group 5 were disconnected from the ventilator during the bypass period . MEASUREMENTS AND MAIN RESULTS Spirometry data , blood gas analysis , oxygen saturation as measured by pulse oximetry , and end-tidal carbon dioxide were recorded 5 minutes before chest opening , 5 minutes before bypass , 5 minutes after bypass , 5 minutes after chest closure and 6 , 12 , 18 , and 24 hours after surgery . There were no differences in compliance and mean airway pressures . Alveolar-to-arterial oxygen gradients increased , and PaO(2 ) decreased significantly ( p < 0.05 ) in all groups 5 minutes after bypass and this trend continued in the postoperative period . Patients from group 3 had higher PaO(2 ) and lower alveolar-to-arterial oxygen gradients , 5 minutes after weaning from bypass ( p < 0.05 ) . Extubation times were similar in all groups . CONCLUSIONS The alveolar-arterial oxygen gradient was lower , and the PaO(2 ) was higher 5 minutes after bypass in patients receiving CPAP ( 100 % O(2 ) ) as compared with those ventilated with high-frequency ventilation Pulmonary dysfunction with impairment of lung function and oxygenation is one of the most serious problems in the early postoperative period after cardiac surgery . In this study we investigated the effect of alveolar recruitment strategy during cardiopulmonary bypass on postoperative gas exchange and lung function . This prospect i ve r and omized study included 32 patients undergoing elective myocardial revascularization with cardiopulmonary bypass .  In 16 patients 5 cm H2O of positive end-expiratory pressure was applied after intubation and maintained until extubation ( Group I ) . In the other 16 patients ( group II ) a positive end expiratory pressure ( PEEP ) of 5 cm H2O was maintained as well but was increased to 14 cm H2O every 20 min for 2 min during cross clamp . Measurements were taken preoperatively , before skin incision , before and after ( 3 , 24 , 48 h ) cardiopulmonary bypass and before discharge ( 6th postoperative day ) . Postoperative gas exchange , extravascular lung water and lung function showed no significant difference between the groups . Postoperative pulmonary function variables were lower in both groups compared to baseline values . In patients with normal preoperative pulmonary function , application of an alveolar recruitment strategy during cardiopulmonary bypass does not improve postoperative gas exchange and lung function after cardiac surgery OBJECTIVE Pulmonary atelectasis and hypoxemia remain considerable problems after cardiac surgery . The objective of this study was to determine the efficacy of consecutive vital capacity maneuvers ( C-VCMs ) to improve oxygenation in patients after cardiac surgery . STUDY DESIGN R and omized , controlled clinical trial . SETTING Tertiary referral teaching center . PARTICIPANTS Ninety-five patients requiring elective cardiac surgery with cardiopulmonary bypass ( CPB ) .  INTERVENTION Patients were r and omly allocated to either C-VCM or control groups . In the C-VCM group , lung inflation at pressure of 35 cmH(2)O was sustained for 15 seconds before separation from CPB and at 30 cmH(2)O for 5 seconds after admission to the intensive care unit ( ICU ) . MEASUREMENTS AND MAIN RESULTS The primary outcome was the ratio of arterial oxygen tension to inspired oxygen fraction measured at the following predetermined time intervals : after induction of anesthesia , 15 minutes after separation from CPB , after admission to the ICU , after 3 hours of positive-pressure ventilation , after extubation , and before ICU discharge . C-VCM result ed in better arterial oxygenation extending from the immediate postoperative period to approximately 24 hours after surgery at the time of ICU discharge . There were no significant adverse events related to C-VCM application . CONCLUSION C-VCM is an effective method to reduce hypoxemia associated with the formation of atelectasis after cardiac surgery with CPB BACKGROUND : The aim of our study was to evaluate the pulmonary effects of noninvasive ventilation ( NIV ) with or without recruitment maneuver ( RM ) after open heart surgery . METHODS : One-hundred patients undergoing coronary artery bypass surgery were r and omized into four groups after the operation : 1 ) RM with sustained inflation during mechanical ventilation postoperatively ( RM group , n = 25 ) ; 2 ) RM combined with NIV applied for 1/2-h periods every 6 h in the first postoperative day after tracheal extubation ( RM-NIV group , n = 25 ) ; 3 ) NIV after tracheal extubation ( NIV group , n = 25 ) ; and 4 ) a control group consisting of patients receiving neither RM nor NIV ( control group , n = 25 ) . Pulmonary function tests , oxygenation index , and atelectasis on chest radiograph were evaluated and compared among the groups . RESULTS : RM provided higher arterial oxygen levels during mechanical ventilation and after tracheal extubation compared to other interventions . Oxygenation was better in the RM-NIV and NIV groups than in the control group ( P = 0.02 and P = 0.008 , respectively ) at the end of the study . The postoperative atelectasis score of the control group ( median : 1 ) was higher than those of the RM ( 1 ; P = 0.03 ) , RM-NIV ( 0 ; P < 0.01 ) and NIV ( 0 ; P < 0.01 ) groups . Pulmonary function of the NIV groups on postoperative day 2 was better than in the other groups , whereas the tests were similar among the groups on postoperative day 7 . CONCLUSIONS : NIV associated with RM provided better oxygenation both during and after the mechanical ventilation period . NIV either alone or in combination with RM provided lower atelectasis scores and better early pulmonary function tests compared to the control group , without a significant difference regarding the duration of mechanical ventilation , intensive care unit stay , and the length of hospitalization .  NIV combined with RM is recommended after open heart surgery to prevent postoperative atelectasis and hypoxemia BACKGROUND Pulmonary dysfunction is one of the most common manifestations of inflammatory response after cardiopulmonary bypass ( CPB ) . OBJECTIVE This prospect i ve r and omized study was conducted to evaluate the effect of a modified ultrafiltration ( MUF ) technique on pulmonary function after CPB in children . METHODS Forty patients weighing from 5 to 10 kg with congenital heart disease who required CPB for primary biventricular operative repair were prospect ively r and omized into two groups . The control group received conventional ultrafiltration ( CUF ) during CPB , and the study group received CUF and MUF .  Pulmonary compliance ( static and dynamic ) and gas exchange capacity of the lung expressed as oxygen index , respiratory index , ventilation index , and alveolar-arterial oxygen pressure difference were measured after intubation ( baseline ) , at the termination of CPB , at the end of MUF , on admission to the ICU , and 6 h postoperatively . RESULTS There was no significant difference in lung compliance and gas exchange between the two groups before CPB . CPB produced a significant decrease in static and dynamic lung compliance in both groups . In the control group , static and dynamic lung compliance decreased from 1.0 + /- 0.3 to 0.90 + /- 0.3 mL/cm/kg and 0.87 + /- 0.2 to 0.71 + /- 0.1 mL/cm/kg ( + /- SE ) [ p = 0.0002 and p = 0.002 , respectively ] . In the study group , static and dynamic lung compliance decreased from 1.0 + /- 0.2 to 0.89 + /- 0.03 mL/cm/kg and 0.94 + /- 0.2 to 0.77 + /- 0.1 mL/cm/kg ( p = 0.002 and p = 0.002 , respectively ) . There was no significant difference in the decrease in static ( p = 0.9 ) or dynamic lung compliance ( p = 0.3 ) between the two groups . MUF produced a significant immediate improvement in both static lung compliance ( 0.89 + /- 0.2 to 0.98 + /- 0.2 mL/cm/kg , p = 0.03 ) and dynamic lung compliance ( 0.77 + /- 0.1 to 0.93 + /- 0.2 mL/cm/kg , p = 0.007 ) . The same was observed regarding the gas exchange capacity . CPB produced a significant decrease in lung gas exchange capacity , and MUF produced a significant immediate improvement in lung gas exchange capacity . The effect of MUF on lung compliance and gas exchange capacity was not sustained after admission to the ICU nor 6 h later postoperatively . There was no significant difference in the time of extubation between the two groups ( 12 + /- 3 h and 13 + /- 2 h , p = 0.4 ) , the length of ICU stay , or the total hospital stay postoperatively . CONCLUSIONS The use of MUF after CPB can produce an immediate improvement in lung compliance and gas exchange capacity , which may effectively minimize pulmonary dysfunction postbiventricular repair of congenital heart disease . However , these improvements are not sustained for the first 6 h postoperatively and do not reduce the duration of postoperative intubation , ICU stay , or total hospital stay BACKGROUND : The aim of our study was to evaluate the pulmonary and hemodynamic effects of two different recruitment maneuvers after open heart surgery . METHODS : Sixty patients undergoing coronary artery bypass surgery  were r and omized into three groups after operation : recruitment maneuver with continuous positive airway pressure ( CPAP ) ( CPAP-40 group , n = 20 ) , recruitment by positive end-expiratory pressure ( PEEP ) ( PEEP-20 group , n = 20 ) , and 5 cm H2O PEEP ( PEEP-5 group , n = 20 ) . In the CPAP-40 group , 40 cm H2O peak inspiratory pressure was applied for 30 s , then PEEP was reduced to 20 cm H2O and ventilation was continued with baseline variables with PEEP decreased until the best Pao2 was achieved . In the PEEP-20 group , 20 cm H2O PEEP was set for 2 min , tidal volume was adjusted to achieve a peak inspiratory airway pressure of 40 cm H2O during the maneuver , then PEEP was decreased until the best Pao2 had been achieved . In the PEEP-5 group , 5 cm H2O PEEP was applied postoperatively . RESULTS : The mean arterial blood pressure of the CPAP-40 group was lower than that of the PEEP-20 ( P < 0.01 ) and PEEP-5 groups ( P < 0.01 ) during the interventions . Oxygenation was higher in both recruitment groups than in the PEEP-5 group during the mechanical ventilation period . There was no significant difference among the groups beyond that period . The atelectasis score of the PEEP-5 group ( 1.3 ± 0.9 ) on postoperative day 1 was higher than that of the CPAP-40 ( 0.65 ± 0.6 ; P = 0.01 ) and PEEP-20 ( 0.65 ± 0.5 ; P = 0.01 ) groups . CONCLUSIONS : The recruitment techniques with postmaneuver PEEP increased oxygenation and decreased atelectasis equally , whereas PEEP-20 provided more stable hemodynamic conditions than the CPAP maneuver In this study , 30 patients undergoing elective myocardial revascularization were divided r and omly in three groups ( 10 patients each ) with different management of the lungs during CPB : Group 1 , lungs deflated ; Group 2 , static inflation with PEEP = 5 cmH2O and FIO2 = 1.0 ; Group 3 , static inflation with PEEP = 5 cmH2O and FIO2 = 0.21 . Measurements ( Qs/Qt , P(A-a)O2 , PaO2 , Cstat , Cdyn , PIP , AUTO-PEEP , Rrs , max , Rrs , min and DRrs ) were performed after the induction of anesthesia ( T0 ) , 20 minutes ( T1 ) and 2 hours ( T2 ) after the end of CPB . Respiratory mechanics data were obtained only at T0 and T2 because the sternal retraction . The Group 1 presented a statistically significant increase in Qs/Qt , P(A-a)O2 and Peak Inspiratory Pressure ( PIP ) ; in this group we noticed also a decrease in PaO2 values , static compliance ( Cstat ) and dynamic compliance ( Cdyn ) values comparing basal versus T1 and T2 values . The Group 2 showed a 
    Output:
    