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: QUESTION What is the effect of the Mapleson C circuit compared with the Laerdal circuit in removing secretions and improving ventilation and gas exchange during manual hyperinflation ? DESIGN Prospect i ve , r and omised , cross-over trial . PARTICIPANTS Twenty patients from a tertiary-level intensive care unit who were being mechanically ventilated . INTERVENTION Manual hyperinflation in side-lying with both the Mapleson C or Laerdal circuit on the one day , one circuit in the morning and one in the afternoon , with a washout period of at least three hours between them . OUTCOME MEASURES Secretion clearance was measured as sputum weight , ventilation was measured as respiratory compliance and tidal volume , while gas exchange was measured as oxygenation and CO2 removal . RESULTS The Mapleson C circuit cleared 0.89 g ( 95 % CI 0.80 to 1.15 ) more secretions than the Laerdal circuit ( p < 0.02 ) . There was no difference between the Mapleson C and the Laerdal circuits on respiratory compliance ( p = 0.81 ) , tidal volume ( p = 0.45 ) , oxygenation ( p = 0.28 ) , or CO2 removal ( p = 0.17 ) . CONCLUSION Although more secretions were cleared using the Mapleson C compared with the Laerdal circuit in this study , this had no consequence in terms of oxygenation and compliance only trended to improve . As the study was underpowered the clinical significance of these findings is not clear STUDY OBJECTIVES To investigate the effect of manual hyperinflation ( MH ) in patients with atelectasis associated with ventilation support . DESIGN Patients were r and omized to either an experimental group or a control group . SETTING Pulmonary ICUs from two hospitals . PATIENTS Twenty-three patients with atelectasis associated with ventilation support . INTERVENTIONS The MH technique was at a rate of 8 to 13 breaths/min for a period of 20 min each session , three times per day for 5 days . The control group received their st and ard prescribed mechanical ventilation without supplemental MH .  Sputum contents ( wet/dry weight ratio , viscosity ) , respiratory system capacity ( spontaneous tidal volume [ Vt ] , maximal inspiratory pressure , rapid shallow breathing index [ f/Vt ] , chest radiograph signs , and Pa(O2)/fraction of inspired oxygen [ Fi(O2 ) ] ) were measured just prior to the MH at day 0 as baseline , and at day 3 and day 6 of the study . MEASUREMENTS AND RESULTS There were significant improvements in scores over the 6-day study in the experimental group compared to the control group in spontaneous Vt ( p = 0.035 ) and chest radiograph signs ( p = 0.040 ) , and a trend toward improvement of f/Vt ( p = 0.066 ) and Pa(O2)/Fi(O2 ) ( p = 0.061 ) after adjustment for covariates . Other outcome variables did not differ significantly between the experimental and control groups . CONCLUSIONS MH performed on patients with atelectasis from ventilation support significantly improved alveolar recruitment A major cause of impaired gas exchange during general anaesthesia is atelectasis , causing pulmonary shunt . A ' vital capacity ' ( VC ) manoeuvre ( i.e. inflation of the lungs up to 40 cm H2O , maintained for 15 s ) may re-exp and atelectasis and improve oxygenation . However , such a manoeuvre may cause adverse cardiovascular effects . Reducing the time of maximal inflation may improve the margin of safety . The aim of this study was to analyse the change over time in the amount of atelectasis during a VC manoeuvre in 12 anaesthetized adults with healthy lungs .  I.v . anaesthesia with controlled mechanical ventilation ( VT 9 ( SD 1 ) ml kg-1 ) was used . For the VC manoeuvre , the lungs were inflated up to an airway pressure ( Paw ) of 40 cm H2O . This pressure was maintained for 26 s. Atelectasis was assessed by analysis of computed x-ray tomography . The amount of atelectasis , measured at the base of the lungs , was 4.0 ( SD 2.7 ) cm2 after induction of anaesthesia . The decrease in the amount of atelectasis over time during the VC manoeuvre was described by a negative exponential function with a time constant of 2.6 s. At an inspired oxygen concentration of 40 % , PaO2 increased from 17.2 ( 4.0 ) kPa before to 22.2 ( 6.0 ) kPa ( P = 0.013 ) after the VC manoeuvre . Thus in anaesthetized adults undergoing mechanical ventilation with healthy lungs , inflation of the lungs to a Paw of 40 cm H2O , maintained for 7 - 8 s only , may re-exp and all previously collapsed lung tissue , as detected by lung computed tomography , and improve oxygenation . We conclude that the previously proposed time for a VC manoeuvre may be halved in such subjects Ventilator-associated pneumonia results from bacterial colonisation of the aerodigestive tract or aspiration of contaminated secretions into the lower airways . As a consequence of infection of the lung parenchyma and alveolitis , accumulation of inflammatory exu date s and infiltration of airway mucosa can lead to unfavourable respiratory mechanics in ventilator-associated pneumonia . Tracheal suction is often employed by nursing staff in the management of mechanically ventilated patients with ventilator-associated pneumonia but this technique has the potential to increase respiratory resistance .  Manual hyperinflation is used by physiotherapists to improve lung volume and mobilise secretions and has been shown to increase lung compliance . The effect of manual hyperinflation on airway resistance has not been studied . This study aims to demonstrate an additional mechanical benefit to the respiratory system when manual hyperinflation and suction techniques are combined , by comparing the application of manual hyperinflation and suction with suction alone on static lung compliance ( C(L ) ) and inspiratory resistance ( R(AW ) ) in mechanically ventilated patients with ventilator-associated pneumonia . Fifteen adult patients with ventilator-associated pneumonia were recruited and acted as their own controls . Manual hyperinflation followed by suction ( manual hyperinflation plus suction ) and suction alone were applied consecutively , in r and om order , on two occasions , four hours apart . Respiratory variables , C(L ) and R(AW ) , were measured five times and the averaged value documented . Data were recorded before , immediately after , and 30 minutes after each intervention protocol . C(L ) increased by 22 % and R(AW ) decreased by 21 % , up to 30 minutes after manual hyperinflation plus suction , but not after suction alone . This study suggests that manual hyperinflation in conjunction with suction induces beneficial changes in respiratory mechanics in mechanically ventilated patients with ventilator-associated pneumonia BACKGROUND AND PURPOSE Manual hyperinflation ( MH ) of the lungs is commonly used by physiotherapists in the treatment of intubated mechanically ventilated patients with the aim of increasing alveolar oxygenation , reversing atelectasis or mobilizing pulmonary secretions . However , the efficacy of MH , used in isolation , has not been clearly established . METHOD This r and omized , controlled trial investigated the effects of MH on lung compliance ( CL ) , the arterial oxygen to fraction of inspired oxygen ratio ( PaO2:FIO2 ) and the alveolar-arterial oxygen tension difference (A-a)PO2 in 100 medically stable , mechanically ventilated subjects who had undergone coronary artery surgery ( CAS ) . Post-CAS subjects were used for this study as they constitute a large , homogeneous and accessible group . Subjects were r and omized to either a control group ( non-MH group ) or to a treatment group ( MH group ) which received MH within four hours of surgery . RESULTS After four minutes of MH there were significant improvements in CL , PaO2:FIO2 and (A-a)PO2 with values remaining above baseline measures at 60 min post-intervention . The mean improvement in CL was 6 ml/cmH2O ( approximately 15 % ) , 56 mmHg for PaO2:FIO2 ( approximately 17 % ) and 29 mmHg for (A-a)PO2 ( approximately 17 % ) immediately post-intervention . No significant changes in mean CL , PaO2:FIO2 or (A-a)PO2 were seen in the non-MH group . CONCLUSIONS MH performed in the stable ventilated patient significantly increased CL and PaO2:FIO2 and decreased (A-a)PO2 , but the clinical significance of this improvement is unclear . Further investigations are required to vali date the findings of this study as well as to determine the therapeutic value of MH on patient outcome OBJECTIVE To compare the effects of manual hyperinflation ( MHI ) and ventilator hyperinflation ( VHI ) delivered to completely se date d and paralyzed patients undergoing mitral valve replacement ( MVR ) while maintaining minute ventilation . METHODS This was a r and omized study with a 2-group , pre-test , post-test experimental design . Effects of hyperinflation were studied on static compliance ( C(stat ) ) , dynamic compliance ( C(dyn ) ) , oxygenation ( Pao(2):Fio(2 ) ) , partial pressure of carbon dioxide in arterial blood ( Paco(2 ) ) , and cologarithm of activity of dissolved hydrogen ions in arterial blood ( pH ) . A sample of 30 patients in the immediate postoperative phase of MVR surgery were included in the study . RESULTS No significant differences were found between the groups . Significant improvements were found in oxygenation at both 1minute and 20minutes after MHI , but only at 1minute after VHI ( P < .05 ) . VHI led to improved C(dyn ) ( P < .05 ) . CONCLUSION In the immediate postoperative phase of MVR , both techniques produced similar effects on respiratory compliance and oxygenation .  MHI produced longer lasting improvements in oxygenation than VHI , whereas VHI produced better improvements in dynamic compliance . Paco(2 ) and pH were maintained by both QUESTION Are oxygenation and static compliance improved immediately after manual hyperinflation following myocardial revascularisation ? Does this lead to earlier extubation and shorter hospital stay ? Does it reduce postoperative pulmonary complications ? DESIGN R and omised controlled trial with concealed allocation , blinded assessment and intention-to-treat analysis . PARTICIPANTS Fifty-five patients who underwent myocardial revascularisation . INTERVENTION After an hour in recovery , the experimental group received manual hyperinflation with positive end expiratory pressure followed by suction while the control group received suction only . OUTCOME MEASURES Oxygenation ( PaO(2 ) in mmHg ) and static lung compliance ( in ml/cmH(2)O ) were measured immediately after suction . Time to extubation ( in minutes ) and length of hospital stay ( in days ) were collected and postoperative pulmonary complications were confirmed by X-ray . RESULTS PaO(2 ) was 11.7 mmHg ( 95 % CI 9.4 to 14.0 ) greater in the experimental group while static compliance was 8.5 ml/cmH(2)0 ( 95 % CI 6.4 to 10.6 ) greater than in the control group . The experimental group was extubated 76 minutes ( 95 % CI 24 to 128 ) earlier than the control group but did not have a shorter length of stay ( mean difference 0.5 days , 95 % CI -0.2 to 1.2 ) . The relative risk of postoperative pulmonary complications was no greater ( RR 0.57 , 95 % Cl 0.20 to 1.60 ) in the experimental group than in the control group . CONCLUSION The group that received early manual hyperinflation had markedly better oxygenation and static compliance as well as shorter mechanical ventilation times than the control group . The length of hospital stay and incidence of postoperative pulmonary complications were similar in the two groups BACKGROUND Manual hyperinflation ( MHI ) and ventilator hyperinflation ( VHI ) are two methods of recruitment maneuvers used in ventilated patients to improve lung compliance and secretion mobilization . The use of VHI may minimize the adverse effects of disconnection from the ventilator , but it is uncertain whether high levels of positive end-expiratory pressure ( PEEP ) would decrease the peak expiratory flow rate ( PEFR ) and consequently affect secretion clearance . OBJECTIVES The aim of this study was to compare the effectiveness of MHI and VHI in terms of clearing pulmonary secretions ( sputum wet weight and PEFR ) , improving static respiratory system compliance and oxygenation ( arterial oxygen tension/fraction of inspired oxygen ) , and altering mean arterial pressure , heart rate , and carbon dioxide output at different levels of PEEP . METHODS This was a r and omized crossover study involving 14 general intensive care patients who were intubated and mechanically ventilated . RESULTS Sputum production was similar in both techniques and levels of PEEP . There were no differences in improvement in oxygenation and static respiratory system compliance between MHI and VHI . However , VHI increased Cst significantly at 30 minutes posttreatment ( P = .012 ) , and a significant difference was observed between levels 5 and 7.5 cmH(2)O ( P = .02 ) of PEEP for MHI . MHI generated higher PEFR than VHI ( P < .05 ) . No adverse change in heart rate or mean arterial pressure was observed during either technique ; 
    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: QUESTION What is the effect of the Mapleson C circuit compared with the Laerdal circuit in removing secretions and improving ventilation and gas exchange during manual hyperinflation ? DESIGN Prospect i ve , r and omised , cross-over trial . PARTICIPANTS Twenty patients from a tertiary-level intensive care unit who were being mechanically ventilated . INTERVENTION Manual hyperinflation in side-lying with both the Mapleson C or Laerdal circuit on the one day , one circuit in the morning and one in the afternoon , with a washout period of at least three hours between them . OUTCOME MEASURES Secretion clearance was measured as sputum weight , ventilation was measured as respiratory compliance and tidal volume , while gas exchange was measured as oxygenation and CO2 removal . RESULTS The Mapleson C circuit cleared 0.89 g ( 95 % CI 0.80 to 1.15 ) more secretions than the Laerdal circuit ( p < 0.02 ) . There was no difference between the Mapleson C and the Laerdal circuits on respiratory compliance ( p = 0.81 ) , tidal volume ( p = 0.45 ) , oxygenation ( p = 0.28 ) , or CO2 removal ( p = 0.17 ) . CONCLUSION Although more secretions were cleared using the Mapleson C compared with the Laerdal circuit in this study , this had no consequence in terms of oxygenation and compliance only trended to improve . As the study was underpowered the clinical significance of these findings is not clear STUDY OBJECTIVES To investigate the effect of manual hyperinflation ( MH ) in patients with atelectasis associated with ventilation support . DESIGN Patients were r and omized to either an experimental group or a control group . SETTING Pulmonary ICUs from two hospitals . PATIENTS Twenty-three patients with atelectasis associated with ventilation support . INTERVENTIONS The MH technique was at a rate of 8 to 13 breaths/min for a period of 20 min each session , three times per day for 5 days . The control group received their st and ard prescribed mechanical ventilation without supplemental MH .  Sputum contents ( wet/dry weight ratio , viscosity ) , respiratory system capacity ( spontaneous tidal volume [ Vt ] , maximal inspiratory pressure , rapid shallow breathing index [ f/Vt ] , chest radiograph signs , and Pa(O2)/fraction of inspired oxygen [ Fi(O2 ) ] ) were measured just prior to the MH at day 0 as baseline , and at day 3 and day 6 of the study . MEASUREMENTS AND RESULTS There were significant improvements in scores over the 6-day study in the experimental group compared to the control group in spontaneous Vt ( p = 0.035 ) and chest radiograph signs ( p = 0.040 ) , and a trend toward improvement of f/Vt ( p = 0.066 ) and Pa(O2)/Fi(O2 ) ( p = 0.061 ) after adjustment for covariates . Other outcome variables did not differ significantly between the experimental and control groups . CONCLUSIONS MH performed on patients with atelectasis from ventilation support significantly improved alveolar recruitment A major cause of impaired gas exchange during general anaesthesia is atelectasis , causing pulmonary shunt . A ' vital capacity ' ( VC ) manoeuvre ( i.e. inflation of the lungs up to 40 cm H2O , maintained for 15 s ) may re-exp and atelectasis and improve oxygenation . However , such a manoeuvre may cause adverse cardiovascular effects . Reducing the time of maximal inflation may improve the margin of safety . The aim of this study was to analyse the change over time in the amount of atelectasis during a VC manoeuvre in 12 anaesthetized adults with healthy lungs .  I.v . anaesthesia with controlled mechanical ventilation ( VT 9 ( SD 1 ) ml kg-1 ) was used . For the VC manoeuvre , the lungs were inflated up to an airway pressure ( Paw ) of 40 cm H2O . This pressure was maintained for 26 s. Atelectasis was assessed by analysis of computed x-ray tomography . The amount of atelectasis , measured at the base of the lungs , was 4.0 ( SD 2.7 ) cm2 after induction of anaesthesia . The decrease in the amount of atelectasis over time during the VC manoeuvre was described by a negative exponential function with a time constant of 2.6 s. At an inspired oxygen concentration of 40 % , PaO2 increased from 17.2 ( 4.0 ) kPa before to 22.2 ( 6.0 ) kPa ( P = 0.013 ) after the VC manoeuvre . Thus in anaesthetized adults undergoing mechanical ventilation with healthy lungs , inflation of the lungs to a Paw of 40 cm H2O , maintained for 7 - 8 s only , may re-exp and all previously collapsed lung tissue , as detected by lung computed tomography , and improve oxygenation . We conclude that the previously proposed time for a VC manoeuvre may be halved in such subjects Ventilator-associated pneumonia results from bacterial colonisation of the aerodigestive tract or aspiration of contaminated secretions into the lower airways . As a consequence of infection of the lung parenchyma and alveolitis , accumulation of inflammatory exu date s and infiltration of airway mucosa can lead to unfavourable respiratory mechanics in ventilator-associated pneumonia . Tracheal suction is often employed by nursing staff in the management of mechanically ventilated patients with ventilator-associated pneumonia but this technique has the potential to increase respiratory resistance .  Manual hyperinflation is used by physiotherapists to improve lung volume and mobilise secretions and has been shown to increase lung compliance . The effect of manual hyperinflation on airway resistance has not been studied . This study aims to demonstrate an additional mechanical benefit to the respiratory system when manual hyperinflation and suction techniques are combined , by comparing the application of manual hyperinflation and suction with suction alone on static lung compliance ( C(L ) ) and inspiratory resistance ( R(AW ) ) in mechanically ventilated patients with ventilator-associated pneumonia . Fifteen adult patients with ventilator-associated pneumonia were recruited and acted as their own controls . Manual hyperinflation followed by suction ( manual hyperinflation plus suction ) and suction alone were applied consecutively , in r and om order , on two occasions , four hours apart . Respiratory variables , C(L ) and R(AW ) , were measured five times and the averaged value documented . Data were recorded before , immediately after , and 30 minutes after each intervention protocol . C(L ) increased by 22 % and R(AW ) decreased by 21 % , up to 30 minutes after manual hyperinflation plus suction , but not after suction alone . This study suggests that manual hyperinflation in conjunction with suction induces beneficial changes in respiratory mechanics in mechanically ventilated patients with ventilator-associated pneumonia BACKGROUND AND PURPOSE Manual hyperinflation ( MH ) of the lungs is commonly used by physiotherapists in the treatment of intubated mechanically ventilated patients with the aim of increasing alveolar oxygenation , reversing atelectasis or mobilizing pulmonary secretions . However , the efficacy of MH , used in isolation , has not been clearly established . METHOD This r and omized , controlled trial investigated the effects of MH on lung compliance ( CL ) , the arterial oxygen to fraction of inspired oxygen ratio ( PaO2:FIO2 ) and the alveolar-arterial oxygen tension difference (A-a)PO2 in 100 medically stable , mechanically ventilated subjects who had undergone coronary artery surgery ( CAS ) . Post-CAS subjects were used for this study as they constitute a large , homogeneous and accessible group . Subjects were r and omized to either a control group ( non-MH group ) or to a treatment group ( MH group ) which received MH within four hours of surgery . RESULTS After four minutes of MH there were significant improvements in CL , PaO2:FIO2 and (A-a)PO2 with values remaining above baseline measures at 60 min post-intervention . The mean improvement in CL was 6 ml/cmH2O ( approximately 15 % ) , 56 mmHg for PaO2:FIO2 ( approximately 17 % ) and 29 mmHg for (A-a)PO2 ( approximately 17 % ) immediately post-intervention . No significant changes in mean CL , PaO2:FIO2 or (A-a)PO2 were seen in the non-MH group . CONCLUSIONS MH performed in the stable ventilated patient significantly increased CL and PaO2:FIO2 and decreased (A-a)PO2 , but the clinical significance of this improvement is unclear . Further investigations are required to vali date the findings of this study as well as to determine the therapeutic value of MH on patient outcome OBJECTIVE To compare the effects of manual hyperinflation ( MHI ) and ventilator hyperinflation ( VHI ) delivered to completely se date d and paralyzed patients undergoing mitral valve replacement ( MVR ) while maintaining minute ventilation . METHODS This was a r and omized study with a 2-group , pre-test , post-test experimental design . Effects of hyperinflation were studied on static compliance ( C(stat ) ) , dynamic compliance ( C(dyn ) ) , oxygenation ( Pao(2):Fio(2 ) ) , partial pressure of carbon dioxide in arterial blood ( Paco(2 ) ) , and cologarithm of activity of dissolved hydrogen ions in arterial blood ( pH ) . A sample of 30 patients in the immediate postoperative phase of MVR surgery were included in the study . RESULTS No significant differences were found between the groups . Significant improvements were found in oxygenation at both 1minute and 20minutes after MHI , but only at 1minute after VHI ( P < .05 ) . VHI led to improved C(dyn ) ( P < .05 ) . CONCLUSION In the immediate postoperative phase of MVR , both techniques produced similar effects on respiratory compliance and oxygenation .  MHI produced longer lasting improvements in oxygenation than VHI , whereas VHI produced better improvements in dynamic compliance . Paco(2 ) and pH were maintained by both QUESTION Are oxygenation and static compliance improved immediately after manual hyperinflation following myocardial revascularisation ? Does this lead to earlier extubation and shorter hospital stay ? Does it reduce postoperative pulmonary complications ? DESIGN R and omised controlled trial with concealed allocation , blinded assessment and intention-to-treat analysis . PARTICIPANTS Fifty-five patients who underwent myocardial revascularisation . INTERVENTION After an hour in recovery , the experimental group received manual hyperinflation with positive end expiratory pressure followed by suction while the control group received suction only . OUTCOME MEASURES Oxygenation ( PaO(2 ) in mmHg ) and static lung compliance ( in ml/cmH(2)O ) were measured immediately after suction . Time to extubation ( in minutes ) and length of hospital stay ( in days ) were collected and postoperative pulmonary complications were confirmed by X-ray . RESULTS PaO(2 ) was 11.7 mmHg ( 95 % CI 9.4 to 14.0 ) greater in the experimental group while static compliance was 8.5 ml/cmH(2)0 ( 95 % CI 6.4 to 10.6 ) greater than in the control group . The experimental group was extubated 76 minutes ( 95 % CI 24 to 128 ) earlier than the control group but did not have a shorter length of stay ( mean difference 0.5 days , 95 % CI -0.2 to 1.2 ) . The relative risk of postoperative pulmonary complications was no greater ( RR 0.57 , 95 % Cl 0.20 to 1.60 ) in the experimental group than in the control group . CONCLUSION The group that received early manual hyperinflation had markedly better oxygenation and static compliance as well as shorter mechanical ventilation times than the control group . The length of hospital stay and incidence of postoperative pulmonary complications were similar in the two groups BACKGROUND Manual hyperinflation ( MHI ) and ventilator hyperinflation ( VHI ) are two methods of recruitment maneuvers used in ventilated patients to improve lung compliance and secretion mobilization . The use of VHI may minimize the adverse effects of disconnection from the ventilator , but it is uncertain whether high levels of positive end-expiratory pressure ( PEEP ) would decrease the peak expiratory flow rate ( PEFR ) and consequently affect secretion clearance . OBJECTIVES The aim of this study was to compare the effectiveness of MHI and VHI in terms of clearing pulmonary secretions ( sputum wet weight and PEFR ) , improving static respiratory system compliance and oxygenation ( arterial oxygen tension/fraction of inspired oxygen ) , and altering mean arterial pressure , heart rate , and carbon dioxide output at different levels of PEEP . METHODS This was a r and omized crossover study involving 14 general intensive care patients who were intubated and mechanically ventilated . RESULTS Sputum production was similar in both techniques and levels of PEEP . There were no differences in improvement in oxygenation and static respiratory system compliance between MHI and VHI . However , VHI increased Cst significantly at 30 minutes posttreatment ( P = .012 ) , and a significant difference was observed between levels 5 and 7.5 cmH(2)O ( P = .02 ) of PEEP for MHI . MHI generated higher PEFR than VHI ( P < .05 ) . No adverse change in heart rate or mean arterial pressure was observed during either technique ; 
    Output:
    