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 There is a growing concern of the potential injurious role of ventilatory over-distention in patients without lung injury . No formal guidelines exist for intraoperative ventilation setting s , but the use of tidal volumes ( VT ) under 10 mL/kg predicted body weight ( PBW ) has been recommended in healthy patients . We explored the incidence and risk factors for receiving large tidal volumes ( VT > 10 mL/kg PBW ) . Methods We performed a cross-sectional analysis of our prospect ively collected perioperative electronic data base for current intraoperative ventilation practice s and risk factors for receiving large tidal volumes ( VT > 10 mL/kg PBW ) . We included all adults undergoing prolonged ( ≥ 4 h ) elective abdominal surgery and collected demographic , preoperative ( comorbidities ) , intraoperative ( i.e. ventilatory setting s , fluid administration ) and postoperative ( outcomes ) information . We compared patients receiving exhaled tidal volumes > 10 mL/kg PBW with those that received 8 - 10 or < 8 mL/kg PBW with univariate and logistic regression analyses . Results Ventilatory setting s were non-uniform in the 429 adults included in the analysis . 17.5 % of all patients received VT > 10 mL/kg PBW . 34.0 % of all obese patients ( body mass index , BMI , ≥ 30 ) , 51 % of all patients with a height < 165 cm , and 34.6 % of all female patients received VT > 10 mL/kg PBW . Conclusions Ventilation with VT > 10 mL/kg PBW is still common , although poor correlation with PBW suggests it may be unintentional . BMI ≥ 30 , female gender and height < 165 cm may predispose to receive large tidal volumes during general anesthesia . Further awareness of patients ' height and PBW is needed to improve intraoperative ventilation practice s. The impact on clinical outcome needs confirmation Objective To examine whether postoperative mechanical ventilation with lower tidal volumes ( VT ) has protective effects on inflammatory responses induced by  cardiopulmonary bypass ( CPB )  surgery in smokers and nonsmokers . Design and setting Prospect i ve , r and omized , controlled clinical trial in the intensive care unit of a university hospital . Patients and participants We examined 44 patients ( 22 smokers , 22 nonsmokers ) immediately after uncomplicated CPB surgery . Interventions Ventilation was applied for 6 h with either VT of either 6 or 12 ml/kg ideal body weight . Measurements and results The time course of serum tumor necrosis factor ( TNF ) α , interleukin ( IL ) 6 , and IL-8 determined 0 , 2 , 4 , and 6 h after r and omization did not differ significantly between the ventilatory strategies . By contrast , in bronchoalveolar lavage fluids sample d after 6 h only TNF-α levels were significantly higher in the high VT group than the low VT group ( 50±111 pg/ml vs. 1±7 pg/ml ) . IL-6 and IL-8 concentrations did not differ between groups . Subgroup analysis of patients with serum TNF-α level higher than 0 pg/ml after surgery revealed lower TNF-α serum levels during lower VT ventilation . All observed effects were small , independent of patients ’ history of smoking , and were not correlated with duration of ventilation and ICU stay . Conclusions Ventilation with lower VT had no or only minor effect on systemic and pulmonary inflammatory responses in patients with healthy lungs after uncomplicated CPB surgery . Our data do not suggest a clinical benefit of using low VT ventilation in these selected patients Introduction In lung cancer surgery , large tidal volume and elevated inspiratory pressure are known risk factors of acute lung ( ALI ) . Mechanical ventilation with low tidal volume has been shown to attenuate lung injuries in critically ill patients . In the current study , we assessed the impact of a protective lung ventilation ( PLV ) protocol in patients undergoing lung cancer resection . Methods We performed a secondary analysis of an observational cohort . Demographic , surgical , clinical and outcome data were prospect ively collected over a 10-year period . The PLV protocol consisted of small tidal volume , limiting maximal pressure ventilation and adding end-expiratory positive pressure along with recruitment maneuvers . Multivariate analysis with logistic regression was performed and data were compared before and after implementation of the PLV protocol : from 1998 to 2003 ( historical group , n = 533 ) and from 2003 to 2008 ( protocol group , n = 558 ) . Results Baseline patient characteristics were similar in the two cohorts , except for a higher cardiovascular risk profile in the intervention group . During one-lung ventilation , protocol -managed patients had lower tidal volume ( 5.3 ± 1.1 vs. 7.1 ± 1.2 ml/kg in historical controls , P = 0.013 ) and higher dynamic compliance ( 45 ± 8 vs. 32 ± 7 ml/cmH2O , P = 0.011 ) . After implementing PLV , there was a decreased incidence of acute lung injury ( from 3.7 % to 0.9 % , P < 0.01 ) and atelectasis ( from 8.8 to 5.0 , P = 0.018 ) , fewer admissions to the intensive care unit ( from 9.4 % vs. 2.5 % , P < 0.001 ) and shorter hospital stay ( from 14.5 ± 3.3 vs. 11.8 ± 4.1 , P < 0.01 ) . When adjusted for baseline characteristics , implementation of the open-lung protocol was associated with a reduced risk of acute lung injury ( adjusted odds ratio of 0.34 with 95 % confidence interval of 0.23 to 0.75 ; P = 0.002 ) . Conclusions Implementing an intraoperative PLV protocol in patients undergoing lung cancer resection was associated with improved postoperative respiratory outcomes as evidence by significantly reduced incidences of acute lung injury and atelectasis along with reduced utilization of intensive care unit re sources Mechanical ventilation ( MV ) may induce an inflammatory alveolar response .  One-lung ventilation ( OLV ) with tidal volumes ( Vt ) as used during two-lung ventilation is a suggested algorithm but may impose mechanical stress of the dependent lung and potentially aggravate alveolar mediator release . We studied whether ventilation with different Vt modifies pulmonary immune function , hemodynamics , and gas exchange .  Thirty-two patients undergoing open thoracic surgery were r and omized to receive either MV with Vt = 10 mL/kg ( n = 16 ) or Vt = 5 mL/kg ( n = 16 ) adjusted to normal Paco2 during and after OLV . Fiberoptic bronchoalveolar lavage of the ventilated lung was performed , and cells , protein , tumor necrosis factor (TNF)-&agr ; , interleukin (IL)-8 , soluble intercellular adhesion molecule (sICAM)-1 , IL-10 , and elastase were determined in the bronchoalveolar lavage . Data were analyzed by parametric or nonparametric tests , as indicated . In all patients , an increase of proinflammatory variables was found . The time courses of intra-alveolar cells , protein , albumin , IL-8 , elastase , and IL-10 did not differ between the groups after OLV and postoperatively . TNF-&agr ; ( 8.4 versus 5.0 & mgr;g/mL ) and sICAM-1 ( 52.7 versus 27.5 & mgr;g/mL ) concentrations were significantly smaller after OLV with Vt = 5 mL/kg . These results indicate that MV may induce epithelial damage and a proinflammatory response in the ventilated lung . Reduction of tidal volume during OLV may reduce alveolar concentrations of TNF-&agr ; and of sICAM-1 STUDY OBJECTIVE To determine whether low tidal ventilation in patients without lung injury results in an increase in the amount of atelectasis and a further impairment of gas exchange during general anesthesia . DESIGN R and omized , single-blind study . SETTING University hospital . PATIENTS 16 adult , ASA physical status I and II patients , who were scheduled for elective excision of intracranial lesion . INTERVENTIONS Patients were r and omly allocated to one of two groups : traditional tidal volume ( V(T ) ) ventilation group ( V(T ) , 10 mL/kg ) and low V(T ) ventilation group ( V(T ) , 6 mL/kg ) after the first computed tomographic ( CT ) scan . MEASUREMENTS AND MAIN RESULTS Atelectasis , as determined by CT and arterial blood gas analysis , was measured before induction , after tracheal intubation , and at the end of operation . After tracheal intubation , CT scan showed atelectasis in both groups . The mean atelectasis area was 4.25 + /- 2.05 cm(2 ) ( 3.32 % + /- 1.94 % ) in the traditional V(T ) ventilation group and 5.56 + /- 3.21 cm(2 ) ( 4.19 % + /- 2.31 % ) in the low V(T ) ventilation group . At the end of operation , there was no significant increase in the amount of atelectasis within the two groups . Arterial blood gas analysis showed no differences after tracheal intubation or at the end of operation in either group . CONCLUSION Ventilation using low V(T)s does not cause more pulmonary collapse than mechanical ventilation using st and ard V(T)s Background : High tidal volumes in patients with acute respiratory distress syndrome and acute lung injury lead to ventilator-induced lung injury and increased mortality . We evaluated the impact of tidal volumes on cardiac surgery outcomes . Methods : We examined prospect ively recorded data from 3,434 consecutive adult patients who underwent cardiac surgery .  Three groups of patients were defined based on the tidal volume delivered on arrival at the intensive care unit : ( 1 ) low : below 10 , ( 2 ) traditional : 10–12 , and ( 3 ) high : more than 12 ml/kg of predicted body weight . We assessed risk factors for three types of organ failure ( prolonged mechanical ventilation , hemodynamic instability , and renal failure ) and a prolonged stay in the intensive care unit . Results : The mean tidal volume/actual weight was 9.2 ml/kg , and the tidal volume/predicted body weight was 11.5 ml/kg . Low , traditional , and high tidal volumes were used in 724 ( 21.1 % ) , 1567 ( 45.6 % ) , and 1,143 patients ( 33.3 % ) , respectively . Independent risks factors for high tidal volumes were body mass index of 30 or more ( odds ratio [ OR ] 6.25 ; CI : 5.26–7.42 ; P < 0.001 ) and female sex ( OR 4.33 ; CI : 3.64–5.15 ; P < 0.001 ) . In the multivariate analysis , high and traditional tidal volumes were independent risk factors for organ failure , multiple organ failure , and prolonged stay in the intensive care unit . Organ failures were associated with increased intensive care unit stay , hospital mortality , and long-term mortality . Conclusion : Tidal volumes of more than 10 ml/kg are risk factors for organ failure and prolonged intensive care unit stay after cardiac surgery . Women and obese patients are particularly at risk of being ventilated with injurious tidal volumes BACKGROUND Minimally invasive esophagectomy ( MIE ) has been advantageous for lowering pulmonary complications compared with open approaches.(1 ) However , pulmonary complications remain the most common morbidity after surgical resection of esophageal cancer.(2,3 ) The aim of this prospect i ve , r and omized , controlled , clinical trial was design ed to see whether low tidal volume ( VT ) could further minimize pulmonary complications after MIE . METHODS Between June 2011 and July 2012 , a total of 101 patients who underwent MIE received left-lung ventilation during thoracoscopic esophagectomy .  All patients received left-lung ventilation during thoracoscopic esophagectomy . Patients were r and omly assigned to a low VT ( 5 mL/kg + 5 cm H2O positive end-expiratory pressure ) preserved ventilation ( PV ) group ( n = 53 ) and a conventional VT ( 8 mL/kg ) controlled ventilation ( CV ) group ( n = 48 ) in the thoracic stage . Alveolar lavage fluid was harvested from the ventilated lung at intubation and at 18 hours after surgery for analysis of interleukin (IL)-1ß , IL-6 , and IL-8 levels . Clinical characteristics , including patient demographics , operation features , and changes in oxygenation index , were recorded and analyzed . Pulmonary complications were identified and statistically compared between the 2 groups . RESULTS The clinical characteristics and operation features were comparable between the 2 groups . IL-1ß , IL-6 , and IL-8 expressions in preoperative alveolar lavage fluid were similar between the 2 groups . Significantly lower IL expressions were observed in the PV group than those in the CV group at 18 hours after MIE ( IL-1ß , 25.42 ± 31.01 vs 94.96 ± 118.24 pg/mL ; IL-6 , 30.86 ± 75.78 vs 92.99 ± 72.90 pg/mL 
    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 There is a growing concern of the potential injurious role of ventilatory over-distention in patients without lung injury . No formal guidelines exist for intraoperative ventilation setting s , but the use of tidal volumes ( VT ) under 10 mL/kg predicted body weight ( PBW ) has been recommended in healthy patients . We explored the incidence and risk factors for receiving large tidal volumes ( VT > 10 mL/kg PBW ) . Methods We performed a cross-sectional analysis of our prospect ively collected perioperative electronic data base for current intraoperative ventilation practice s and risk factors for receiving large tidal volumes ( VT > 10 mL/kg PBW ) . We included all adults undergoing prolonged ( ≥ 4 h ) elective abdominal surgery and collected demographic , preoperative ( comorbidities ) , intraoperative ( i.e. ventilatory setting s , fluid administration ) and postoperative ( outcomes ) information . We compared patients receiving exhaled tidal volumes > 10 mL/kg PBW with those that received 8 - 10 or < 8 mL/kg PBW with univariate and logistic regression analyses . Results Ventilatory setting s were non-uniform in the 429 adults included in the analysis . 17.5 % of all patients received VT > 10 mL/kg PBW . 34.0 % of all obese patients ( body mass index , BMI , ≥ 30 ) , 51 % of all patients with a height < 165 cm , and 34.6 % of all female patients received VT > 10 mL/kg PBW . Conclusions Ventilation with VT > 10 mL/kg PBW is still common , although poor correlation with PBW suggests it may be unintentional . BMI ≥ 30 , female gender and height < 165 cm may predispose to receive large tidal volumes during general anesthesia . Further awareness of patients ' height and PBW is needed to improve intraoperative ventilation practice s. The impact on clinical outcome needs confirmation Objective To examine whether postoperative mechanical ventilation with lower tidal volumes ( VT ) has protective effects on inflammatory responses induced by  cardiopulmonary bypass ( CPB )  surgery in smokers and nonsmokers . Design and setting Prospect i ve , r and omized , controlled clinical trial in the intensive care unit of a university hospital . Patients and participants We examined 44 patients ( 22 smokers , 22 nonsmokers ) immediately after uncomplicated CPB surgery . Interventions Ventilation was applied for 6 h with either VT of either 6 or 12 ml/kg ideal body weight . Measurements and results The time course of serum tumor necrosis factor ( TNF ) α , interleukin ( IL ) 6 , and IL-8 determined 0 , 2 , 4 , and 6 h after r and omization did not differ significantly between the ventilatory strategies . By contrast , in bronchoalveolar lavage fluids sample d after 6 h only TNF-α levels were significantly higher in the high VT group than the low VT group ( 50±111 pg/ml vs. 1±7 pg/ml ) . IL-6 and IL-8 concentrations did not differ between groups . Subgroup analysis of patients with serum TNF-α level higher than 0 pg/ml after surgery revealed lower TNF-α serum levels during lower VT ventilation . All observed effects were small , independent of patients ’ history of smoking , and were not correlated with duration of ventilation and ICU stay . Conclusions Ventilation with lower VT had no or only minor effect on systemic and pulmonary inflammatory responses in patients with healthy lungs after uncomplicated CPB surgery . Our data do not suggest a clinical benefit of using low VT ventilation in these selected patients Introduction In lung cancer surgery , large tidal volume and elevated inspiratory pressure are known risk factors of acute lung ( ALI ) . Mechanical ventilation with low tidal volume has been shown to attenuate lung injuries in critically ill patients . In the current study , we assessed the impact of a protective lung ventilation ( PLV ) protocol in patients undergoing lung cancer resection . Methods We performed a secondary analysis of an observational cohort . Demographic , surgical , clinical and outcome data were prospect ively collected over a 10-year period . The PLV protocol consisted of small tidal volume , limiting maximal pressure ventilation and adding end-expiratory positive pressure along with recruitment maneuvers . Multivariate analysis with logistic regression was performed and data were compared before and after implementation of the PLV protocol : from 1998 to 2003 ( historical group , n = 533 ) and from 2003 to 2008 ( protocol group , n = 558 ) . Results Baseline patient characteristics were similar in the two cohorts , except for a higher cardiovascular risk profile in the intervention group . During one-lung ventilation , protocol -managed patients had lower tidal volume ( 5.3 ± 1.1 vs. 7.1 ± 1.2 ml/kg in historical controls , P = 0.013 ) and higher dynamic compliance ( 45 ± 8 vs. 32 ± 7 ml/cmH2O , P = 0.011 ) . After implementing PLV , there was a decreased incidence of acute lung injury ( from 3.7 % to 0.9 % , P < 0.01 ) and atelectasis ( from 8.8 to 5.0 , P = 0.018 ) , fewer admissions to the intensive care unit ( from 9.4 % vs. 2.5 % , P < 0.001 ) and shorter hospital stay ( from 14.5 ± 3.3 vs. 11.8 ± 4.1 , P < 0.01 ) . When adjusted for baseline characteristics , implementation of the open-lung protocol was associated with a reduced risk of acute lung injury ( adjusted odds ratio of 0.34 with 95 % confidence interval of 0.23 to 0.75 ; P = 0.002 ) . Conclusions Implementing an intraoperative PLV protocol in patients undergoing lung cancer resection was associated with improved postoperative respiratory outcomes as evidence by significantly reduced incidences of acute lung injury and atelectasis along with reduced utilization of intensive care unit re sources Mechanical ventilation ( MV ) may induce an inflammatory alveolar response .  One-lung ventilation ( OLV ) with tidal volumes ( Vt ) as used during two-lung ventilation is a suggested algorithm but may impose mechanical stress of the dependent lung and potentially aggravate alveolar mediator release . We studied whether ventilation with different Vt modifies pulmonary immune function , hemodynamics , and gas exchange .  Thirty-two patients undergoing open thoracic surgery were r and omized to receive either MV with Vt = 10 mL/kg ( n = 16 ) or Vt = 5 mL/kg ( n = 16 ) adjusted to normal Paco2 during and after OLV . Fiberoptic bronchoalveolar lavage of the ventilated lung was performed , and cells , protein , tumor necrosis factor (TNF)-&agr ; , interleukin (IL)-8 , soluble intercellular adhesion molecule (sICAM)-1 , IL-10 , and elastase were determined in the bronchoalveolar lavage . Data were analyzed by parametric or nonparametric tests , as indicated . In all patients , an increase of proinflammatory variables was found . The time courses of intra-alveolar cells , protein , albumin , IL-8 , elastase , and IL-10 did not differ between the groups after OLV and postoperatively . TNF-&agr ; ( 8.4 versus 5.0 & mgr;g/mL ) and sICAM-1 ( 52.7 versus 27.5 & mgr;g/mL ) concentrations were significantly smaller after OLV with Vt = 5 mL/kg . These results indicate that MV may induce epithelial damage and a proinflammatory response in the ventilated lung . Reduction of tidal volume during OLV may reduce alveolar concentrations of TNF-&agr ; and of sICAM-1 STUDY OBJECTIVE To determine whether low tidal ventilation in patients without lung injury results in an increase in the amount of atelectasis and a further impairment of gas exchange during general anesthesia . DESIGN R and omized , single-blind study . SETTING University hospital . PATIENTS 16 adult , ASA physical status I and II patients , who were scheduled for elective excision of intracranial lesion . INTERVENTIONS Patients were r and omly allocated to one of two groups : traditional tidal volume ( V(T ) ) ventilation group ( V(T ) , 10 mL/kg ) and low V(T ) ventilation group ( V(T ) , 6 mL/kg ) after the first computed tomographic ( CT ) scan . MEASUREMENTS AND MAIN RESULTS Atelectasis , as determined by CT and arterial blood gas analysis , was measured before induction , after tracheal intubation , and at the end of operation . After tracheal intubation , CT scan showed atelectasis in both groups . The mean atelectasis area was 4.25 + /- 2.05 cm(2 ) ( 3.32 % + /- 1.94 % ) in the traditional V(T ) ventilation group and 5.56 + /- 3.21 cm(2 ) ( 4.19 % + /- 2.31 % ) in the low V(T ) ventilation group . At the end of operation , there was no significant increase in the amount of atelectasis within the two groups . Arterial blood gas analysis showed no differences after tracheal intubation or at the end of operation in either group . CONCLUSION Ventilation using low V(T)s does not cause more pulmonary collapse than mechanical ventilation using st and ard V(T)s Background : High tidal volumes in patients with acute respiratory distress syndrome and acute lung injury lead to ventilator-induced lung injury and increased mortality . We evaluated the impact of tidal volumes on cardiac surgery outcomes . Methods : We examined prospect ively recorded data from 3,434 consecutive adult patients who underwent cardiac surgery .  Three groups of patients were defined based on the tidal volume delivered on arrival at the intensive care unit : ( 1 ) low : below 10 , ( 2 ) traditional : 10–12 , and ( 3 ) high : more than 12 ml/kg of predicted body weight . We assessed risk factors for three types of organ failure ( prolonged mechanical ventilation , hemodynamic instability , and renal failure ) and a prolonged stay in the intensive care unit . Results : The mean tidal volume/actual weight was 9.2 ml/kg , and the tidal volume/predicted body weight was 11.5 ml/kg . Low , traditional , and high tidal volumes were used in 724 ( 21.1 % ) , 1567 ( 45.6 % ) , and 1,143 patients ( 33.3 % ) , respectively . Independent risks factors for high tidal volumes were body mass index of 30 or more ( odds ratio [ OR ] 6.25 ; CI : 5.26–7.42 ; P < 0.001 ) and female sex ( OR 4.33 ; CI : 3.64–5.15 ; P < 0.001 ) . In the multivariate analysis , high and traditional tidal volumes were independent risk factors for organ failure , multiple organ failure , and prolonged stay in the intensive care unit . Organ failures were associated with increased intensive care unit stay , hospital mortality , and long-term mortality . Conclusion : Tidal volumes of more than 10 ml/kg are risk factors for organ failure and prolonged intensive care unit stay after cardiac surgery . Women and obese patients are particularly at risk of being ventilated with injurious tidal volumes BACKGROUND Minimally invasive esophagectomy ( MIE ) has been advantageous for lowering pulmonary complications compared with open approaches.(1 ) However , pulmonary complications remain the most common morbidity after surgical resection of esophageal cancer.(2,3 ) The aim of this prospect i ve , r and omized , controlled , clinical trial was design ed to see whether low tidal volume ( VT ) could further minimize pulmonary complications after MIE . METHODS Between June 2011 and July 2012 , a total of 101 patients who underwent MIE received left-lung ventilation during thoracoscopic esophagectomy .  All patients received left-lung ventilation during thoracoscopic esophagectomy . Patients were r and omly assigned to a low VT ( 5 mL/kg + 5 cm H2O positive end-expiratory pressure ) preserved ventilation ( PV ) group ( n = 53 ) and a conventional VT ( 8 mL/kg ) controlled ventilation ( CV ) group ( n = 48 ) in the thoracic stage . Alveolar lavage fluid was harvested from the ventilated lung at intubation and at 18 hours after surgery for analysis of interleukin (IL)-1ß , IL-6 , and IL-8 levels . Clinical characteristics , including patient demographics , operation features , and changes in oxygenation index , were recorded and analyzed . Pulmonary complications were identified and statistically compared between the 2 groups . RESULTS The clinical characteristics and operation features were comparable between the 2 groups . IL-1ß , IL-6 , and IL-8 expressions in preoperative alveolar lavage fluid were similar between the 2 groups . Significantly lower IL expressions were observed in the PV group than those in the CV group at 18 hours after MIE ( IL-1ß , 25.42 ± 31.01 vs 94.96 ± 118.24 pg/mL ; IL-6 , 30.86 ± 75.78 vs 92.99 ± 72.90 pg/mL 
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