Mechanical ventilation strategies and inflammatory responses to cardiac surgery: a prospective randomized clinical trial Impact of intraoperative lung-protective interventions in patients undergoing lung cancer surgery Effect of low tidal volume ventilation on atelectasis in patients during general anesthesia: a computed tomographic scan. Protective Mechanical Ventilation during General Anesthesia for Open Abdominal Surgery Improves Postoperative Pulmonary Function The impact of tidal volume on pulmonary complications following minimally invasive esophagectomy: a randomized and controlled study. Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome. Evolution of mortality over time in patients receiving mechanical ventilation. [Effects of the lung protective ventilatory strategy on proinflammatory cytokine release during one-lung ventilation]. Rationale and study design of PROVHILO - a worldwide multicenter randomized controlled trial on protective ventilation during general anesthesia for open abdominal surgery Mechanical Ventilation with Lower Tidal Volumes and Positive End-expiratory Pressure Prevents Pulmonary Inflammation in Patients without Preexisting Lung Injury Protective Ventilation Influences Systemic Inflammation after Esophagectomy: A Randomized Controlled Study The effect of low versus high tidal volume ventilation on inflammatory markers in healthy individuals undergoing posterior spine fusion in the prone position: a randomized controlled trial. The efficacy of activated protein C for the treatment of sepsis: incorporating observational evidence with a Bayesian approach Therapeutic hypercapnia reduces pulmonary and systemic injury following in vivo lung reperfusion. The Effects of Different Ventilatory Settings on Pulmonary and Systemic Inflammatory Responses During Major Surgery A high positive end-expiratory pressure, low tidal volume ventilatory strategy improves outcome in persistent acute respiratory distress syndrome: A randomized, controlled trial* [Effects of different mechanical ventilation methods on oxygenation and shunt fraction in patients undergoing valve replacement]. Effects of protective and conventional mechanical ventilation on pulmonary function and systemic cytokine release after cardiopulmonary bypass A trial of intraoperative low-tidal-volume ventilation in abdominal surgery. A randomized comparison of different ventilator strategies during thoracotomy for pulmonary resection. Protective ventilation attenuates postoperative pulmonary dysfunction in patients undergoing cardiopulmonary bypass. [Laryngeal mask anesthesia in video-assisted thoracoscopic surgery for pulmonary bulla: comparison with intubation anesthesia]. Ventilation strategy for video-assisted thoracoscopic clipping of patent ductus arteriosus in children. Hypercapnic acidosis is protective in an in vivo model of ventilator-induced lung injury. Influence of low tidal volume ventilation on time to extubation in cardiac surgical patients. Mechanical ventilation affects inflammatory mediators in patients undergoing cardiopulmonary bypass for cardiac surgery: a randomized clinical trial. [Influence of tidal volume on functional residual capacity during general anesthesia]. Mechanical Ventilation with Lower Tidal Volumes and Positive End-expiratory Pressure Prevents Alveolar Coagulation in Patients without Lung Injury
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 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 : The impact of intraoperative ventilation on postoperative pulmonary complications is not defined . The authors aim ed at determining the effectiveness of protective mechanical ventilation during open abdominal surgery on a modified Clinical Pulmonary Infection Score as primary outcome and postoperative pulmonary function . Methods : Prospect i ve r and omized , open-label , clinical trial performed in 56 patients scheduled to undergo elective open abdominal surgery lasting more than 2 h. Patients were assigned by envelopes to mechanical ventilation with tidal volume of 9 ml/kg ideal body weight and zero-positive end-expiratory pressure ( st and ard ventilation strategy ) or tidal volumes of 7 ml/kg ideal body weight , 10 cm H2O positive end-expiratory pressure , and recruitment maneuvers ( protective ventilation strategy ) . Modified Clinical Pulmonary Infection Score , gas exchange , and pulmonary functional tests were measured preoperatively , as well as at days 1 , 3 , and 5 after surgery . Results : Patients ventilated protectively showed better pulmonary functional tests up to day 5 , fewer alterations on chest x-ray up to day 3 and higher arterial oxygenation in air at days 1 , 3 , and 5 ( mmHg ; mean ± SD ) : 77.1 ± 13.0 versus 64.9 ± 11.3 ( P = 0.0006 ) , 80.5 ± 10.1 versus 69.7 ± 9.3 ( P = 0.0002 ) , and 82.1 ± 10.7 versus 78.5 ± 21.7 ( P = 0.44 ) respectively . The modified Clinical Pulmonary Infection Score was lower in the protective ventilation strategy at days 1 and 3 . The percentage of patients in hospital at day 28 after surgery was not different between groups ( 7 vs. 15 % respectively , P = 0.42 ) . Conclusion : A protective ventilation strategy during abdominal surgery lasting more than 2 h improved respiratory function and reduced the modified Clinical Pulmonary Infection Score without affecting length of hospital stay 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 ; IL-8 , 258.75 ± 188.24 vs 403.95 ± 151.44 pg/mL ; all P < .05 ) . The 18-hour postoperative oxygenation index was lower in the CV group than that in the PV group ( 292.85 ± 28.74 vs 326.35 ± 34.43 ; P = .046 ) . Pulmonary complications were observed in 18 cases of our series , occurring more frequently on the ventilation side ( right , 6 cases ; and left , 12 cases ) . All patients were cured by conservative therapy without severe sequelae . The occurrence of pulmonary complications in the PV group was lower than that in the CV group ( 9.43 % vs 27.08 % ; P = .021 ) . CONCLUSIONS Lung injury due to intraoperative single-lung ventilation may contribute to pulmonary complications after MIE . Low VT ventilation could decrease ventilation-associated lung inflammation , thus minimizing pulmonary complications after MIE . Further studies , based on a larger volume of population s , are required to confirm these findings BACKGROUND Traditional approaches to mechanical ventilation use tidal volumes of 10 to 15 ml per kilogram of body weight and may cause stretch-induced lung injury in patients with acute lung injury and the acute respiratory distress syndrome . We therefore conducted a trial to determine whether ventilation with lower tidal volumes would improve the clinical outcomes in these patients . METHODS Patients with acute lung injury and the acute respiratory distress syndrome were enrolled in a multicenter , r and omized trial . The trial compared traditional ventilation treatment , which involved an initial tidal volume of 12 ml per kilogram of predicted body weight and an airway pressure measured after a 0.5-second pause at the end of inspiration ( plateau pressure ) of 50 cm of water or less , with ventilation with a lower tidal volume , which involved an initial tidal volume of 6 ml per kilogram of predicted body weight and a plateau pressure of 30 cm of water or less . The primary outcomes were death before a patient was discharged home and was breathing without assistance and the number of days without ventilator use from day 1 to day 28 . RESULTS The trial was stopped after the enrollment of 861 patients because  mortality was lower in the group treated with lower tidal volumes than in the group treated with traditional tidal volumes ( 31.0 percent vs. 39.8 percent , P=0.007 ) , and the number of days without ventilator use during the first 28 days after r and omization was greater in this group ( mean [ + /-SD ] , 12+/-11 vs. 10+/-11 ; P=0.007 ) . The mean tidal volumes on days 1 to 3 were 6.2+/-0.8 and 11.8+/-0.8 ml per kilogram of predicted body weight ( P<0.001 ) , respectively , and the mean plateau pressures were 25+/-6 and 33+/-8 cm of water ( P<0.001 ) , respectively . CONCLUSIONS In patients with acute lung injury and the acute respiratory distress syndrome , mechanical ventilation with a lower tidal volume than is traditionally used results in decreased mortality and increases the number of days without ventilator use RATIONALE Baseline characteristics and management have changed over time in patients requiring mechanical ventilation ;  however , the impact of these changes on patient outcomes is unclear . OBJECTIVES To estimate whether mortality in mechanically ventilated patients has changed over time . METHODS Prospect i ve cohort studies conducted in 1998 , 2004 , and 2010 , including patients receiving mechanical ventilation for more than 12 hours in a 1-month period , from 927 units in 40 countries . To examine effects over time on mortality in intensive care units , we performed generalized estimating equation models . MEASUREMENTS AND MAIN RESULTS We included 18,302 patients . The reasons for initiating mechanical ventilation varied significantly among cohorts . Ventilatory management  changed over time ( P < 0.001 ) , with increased use of noninvasive positive-pressure ventilation ( 5 % in 1998 to 14 % in 2010 ) , a decrease in tidal volume ( mean 8.8 ml/kg actual body weight [ SD = 2.1 ] in 1998 to 6.9 ml/kg [ SD = 1.9 ] in 2010 ) , and an increase in applied positive end-expiratory pressure ( mean 4.2 cm H2O [ SD = 3.8 ] in 1998 to 7.0 cm of H2O [ SD = 3.0 ] in 2010 ) . Crude mortality in the intensive care unit decreased in 2010 compared with 1998 ( 28 versus 31 % ; odds ratio , 0.87 ; 95 % confidence interval , 0.80 - 0.94 ) , despite a similar complication rate . Hospital mortality decreased similarly . After adjusting for baseline and management variables , this difference remained significant ( odds ratio , 0.78 ; 95 % confidence interval , 0.67 - 0.92 ) . CONCLUSIONS Patient characteristics and ventilation practice s have changed over time , and outcomes of mechanically ventilated patients have improved . Clinical trials registered with www . clinical trials.gov ( NCT01093482 ) BACKGROUND & OBJECTIVE A prolonged period of one-lung ventilation(OLV ) is required during thoracic surgery and this may activate cytokine release and cause lung inflammatory response . The lung protective ventilatory strategy has reduced lung and systemic cytokine release and achieved remarkable curative effect in patients with acute respiratory distress syndrome ( ARDS ) . This study was to investigate the effect of the lung protective ventilatory strategy on proinflammatory cytokine release during OLV in patients underwent thoracic surgery . METHODS Forty patients underwent esophagectomy were r and omly divided into conventional ventilation ( CV ) group ( n=20 ) and protective ventilation ( PV ) group ( n=20 ) . In CV group , all patients received two-lung ventilation ( TLV ) and OLV with a tidal volume ( VT ) of 10 mL/kg and an inspiration/expiration ratio ( I/E ) of 1:1.5 . In PV group , all patients received TLV with a VT of 10 mL/kg and an I/E ratio of 1:1.5 , and received OLV with a VT of 5 - 6 mL/kg and an I/E ratio of 1:1 , along with positive end-expiratory pressure ( PEEP ) preset at 3 - 5 cm H2O . Blood sample s of 3 mL were extracted at three time courses , which were after tracheal intubation ( T1 ) , 120 min after OLV ( T2 ) and 24 h after operation ( T3 ) , to analyze concentrations of interleukin (IL)-6 and IL-8 in the two groups . Values of airway peak pressure ( Ppeak ) , airway plateau pressure ( Pplat ) , and airway resistance(Raw)were also recorded using side stream spirometry . RESULTS In CV group , concentrations of IL-6 and IL-8 at T2 [ ( 269.4+/-57.2 ) ng/L , ( 180.8+/-35.0 ) ng/L ] and T3[(335.8+/-98.7 ) ng/L,(178.5+/-18.3 ) ng/L ] were significantly increased as compared with those at T1 [ ( 17.0+/-5.4 ) ng/L,(18.2+/-2.8 ) ng/L](P<0.05 ) . In PV group , concentrations of IL-6 and IL-8 at T2 [ ( 209.3+/-55.7 ) ng/L ] , ( 115.3+/-71.5 ) ng/L ] and T3 [ ( 278.2+/-100.8 ) ng/L,(124.2+/-40.1 ) ng/L ] were significantly increased as compared with those at T1[(20.0+/-7.1 ) ng/L,(15.3+/-3.6 ) ng/L ] ( P<0.05 ) . Concentrations of IL-6 and IL-8 at T2 and T3 were significantly higher in CV group than in PV group ( P<0.05 ) . Ppeak , Pplat and Raw at T2 were significantly higher in CV group [ ( 33.6+/-4.6 cmH2O,(21.5+/-3.1 ) cmH2O , ( 26.3+/-2.1 ) cmH2O.L(-1).S(-1 ) ] than in PV group [ ( 26.7+/-3.5 ) cmH2O , ( 12.4+/-2.1 ) cmH2O , ( 18.3+/-2.3 ) cmH2O.L(-1).S(-1)](P<0.05 ) . CONCLUSIONS Concentrations of IL-6 and IL-8 are increased during and after OLV in thoracic surgery . The lung protective ventilatory strategy can reduce the airway pressure and airway resistance during OLV , decrease the release of IL-6 and IL-8 , and inhibit lung inflammatory responses during OLV and postoperatively Background Post-operative pulmonary complications add to the morbidity and mortality of surgical patients , in particular after general anesthesia > 2 hours for abdominal surgery . Whether a protective mechanical ventilation strategy with higher levels of positive end-expiratory pressure ( PEEP ) and repeated recruitment maneuvers ; the " open lung strategy " , protects against post-operative pulmonary complications is uncertain . The present study aims at comparing a protective mechanical ventilation strategy with a conventional mechanical ventilation strategy during general anesthesia for abdominal non-laparoscopic surgery . Methods The PROtective Ventilation using HIgh versus LOw positive end-expiratory pressure ( " PROVHILO " ) trial is a worldwide investigator-initiated multicenter r and omized controlled two-arm study . Nine hundred patients scheduled for non-laparoscopic abdominal surgery at high or intermediate risk for post-operative pulmonary complications are r and omized to mechanical ventilation with the level of PEEP at 12 cmH2O with recruitment maneuvers ( the lung-protective strategy ) or mechanical ventilation with the level of PEEP at maximum 2 cmH2O without recruitment maneuvers ( the conventional strategy ) . The primary endpoint is any post-operative pulmonary complication . Discussion The PROVHILO trial is the first r and omized controlled trial powered to investigate whether an open lung mechanical ventilation strategy in short-term mechanical ventilation prevents against postoperative pulmonary complications . Trial registration IS RCT N : IS RCT Background : Mechanical ventilation with high tidal volumes aggravates lung injury in patients with acute lung injury or acute respiratory distress syndrome . The authors sought to determine the effects of short-term mechanical ventilation on local inflammatory responses in patients without preexisting lung injury . Methods : Patients scheduled to undergo an elective surgical procedure ( lasting ≥5 h ) were r and omly assigned to mechanical ventilation with either higher tidal volumes of 12 ml/kg ideal body weight and no positive end-expiratory pressure ( PEEP ) or lower tidal volumes of 6 ml/kg and 10 cm H2O PEEP . After induction of anesthesia and 5 h thereafter , bronchoalveolar lavage fluid and /or blood was investigated for polymorphonuclear cell influx , changes in levels of inflammatory markers , and nucleosomes . Results : Mechanical ventilation with lower tidal volumes and PEEP ( n = 21 ) attenuated the increase of pulmonary levels of interleukin (IL)-8 , myeloperoxidase , and elastase as seen with higher tidal volumes and no PEEP ( n = 19 ) . Only for myeloperoxidase , a difference was found between the two ventilation strategies after 5 h of mechanical ventilation ( P < 0.01 ) . Levels of tumor necrosis factor α , IL-1α , IL-1β , IL-6 , macrophage inflammatory protein 1α , and macrophage inflammatory protein 1β in the bronchoalveolar lavage fluid were not affected by mechanical ventilation . Plasma levels of IL-6 and IL-8 increased with mechanical ventilation , but there were no differences between the two ventilation groups . Conclusion : The use of lower tidal volumes and PEEP may limit pulmonary inflammation in mechanically ventilated patients without preexisting lung injury . The specific contribution of both lower tidal volumes and PEEP on the protective effects of the lung should be further investigated Background : Esophagectomy induces a systemic inflammatory response whose extent has been recognized as a predictive factor of postoperative respiratory morbidity . The aim of this study was to determine the effectiveness of a protective ventilatory strategy to reduce systemic inflammation in patients undergoing esophagectomy . Methods : The authors prospect ively investigated 52 patients undergoing planned esophagectomy for cancer . Patients were r and omly assigned to a conventional ventilation strategy ( n = 26 ; tidal volume of 9 ml/kg during two-lung and one-lung ventilation ; no positive end-expiratory pressure ) or a protective ventilation strategy ( n = 26 ; tidal volume of 9 ml/kg during two-lung ventilation , reduced to 5 ml/kg during one-lung ventilation ; positive end-expiratory pressure 5 cm H2O throughout the operative time ) . Results : Plasmatic levels of interleukin (IL)-1&bgr ; , IL-6 , IL-8 , and tumor necrosis factor & agr ; were measured perioperatively and postoperatively . Pulmonary function and postoperative evolution were also evaluated . Patients who received protective strategy had lower blood levels of IL-1&bgr ; , IL-6 , and IL-8 at the end of one-lung ventilation ( 0.24 [ 0.15–0.40 ] vs. 0.56 [ 0.38–0.89 ] pg/ml , P < 0.001 ; 91 [ 61–117 ] vs. 189 [ 127–294 ] pg/ml , P < 0.001 ; and 30 [ 22–45 ] vs. 49 [ 29–69 ] pg/ml , P < 0.05 , respectively ) and 18 h postoperatively ( 0.18 [ 0.13–0.30 ] vs. 0.43 [ 0.34–0.54 ] pg/ml , P < 0.001 ; 54 [ 36–89 ] vs. 116 [ 78–208 ] pg/ml , P < 0.001 ; 16 [ 11–24 ] vs. 35 [ 28–53 ] pg/ml , P < 0.001 , respectively ) . Protective strategy result ed in higher oxygen partial pressure to inspired oxygen fraction ratio during one-lung ventilation and 1 h postoperatively and in a reduction of postoperative mechanical ventilation duration ( 115 ± 38 vs. 171 ± 57 min , P < 0.001 ) . Conclusion : A protective ventilatory strategy decreases the proinflammatory systemic response after esophagectomy , improves lung function , and results in earlier extubation STUDY OBJECTIVE To evaluate the effect of ventilation strategy on markers of inflammation in patients undergoing spine surgery in the prone position . DESIGN R and omized controlled trial . SETTING University-affiliated teaching hospital . PATIENTS 26 ASA physical status 1 and 2 patients scheduled for elective primary lumbar decompression and fusion in the prone position . INTERVENTIONS Patients were r and omized to receive mechanical ventilation  with either a tidal volume ( V(T ) ) of 12 mL/kg ideal body weight with zero positive end-expiratory pressure ( PEEP ) or V(T ) of 6 mL/kg ideal body weight with PEEP of 8 cm H(2)O. MEASUREMENTS Plasma levels of interleukin (IL)-6 and IL-8 were determined at the beginning of ventilation and at 6 and 12 hours later . Urinary levels of desmosine were determined at the beginning of ventilation and on postoperative days 1 and 3 . MAIN RESULTS A significant increase in IL-6 , IL-8 , and urine desmosine levels was noted over time compared with baseline ( P < 0.01 ) . However , no significant difference in the levels of markers was seen between the groups at any time point when controlling for demographics , ASA physical status , body mass index , duration of ventilation , or estimated blood loss . CONCLUSIONS Although markers of inflammation are increased after posterior spine fusion surgery , ventilation strategy has minimal impact on markers of systemic inflammation Objective The present study aim ed to combine observational evidence with r and omised controlled trials ( RCTs ) by using the Bayesian approach . Data sources Electronic data bases , including PubMed , Cochrane Central Register of Controlled Trials ( CENTRAL ) , ISI Web of Science , EMBASE and EBSCO were search ed from inception to January 2014 . Study eligibility RCTs and observational studies ( OS ) investigating the effectiveness of activated protein C ( aPC ) on mortality reduction were included for analysis . Participants Patients with sepsis . Intervention aPC . Synthesis methods Observational evidence was incorporated into the analysis by using power transformed priors in a Bayesian . Trial sequential analysis was performed to examine changes over time and whether further studies need to be conducted . Main results a total of 7 RCTs and 12 OS were included for the analysis . There was moderate heterogeneity among included RCTs ( I2=48.6 % , p=0.07 ) . The pooled OR for mortality from RCTs was 1.00 ( 95 % CI 0.84 to 1.19 ) . In OS , there was potential publication bias as indicated by the funnel plot and the pooled OR for mortality with the use of aPC was 0.67 ( 95 % CI 0.62 to 0.72 ) . The pooled effect sizes of RCTs were changed by using different power transform priors derived from observational evidence . When observational evidence was used at its ‘ face value ’ , the treatment effect of aPC was statistically significant in reducing mortality . Conclusions while RCT evidence showed no beneficial effect of aPC on sepsis , observational evidence showed a significant treatment effect of aPC . By using power transform priors in Bayesian model , we explicitly demonstrated how RCT evidence could be changed by observational evidence . Trial registration number The protocol for the current study was registered in PROSPERO ( registration number : CRD42014009562 ) Permissive hypercapnia , involving tolerance to elevated Pa(CO(2 ) ) , is associated with reduced acute lung injury ( ALI ) , thought to result from reduced mechanical stretch , and improved outcome in ARDS . However , deliberately elevating inspired CO(2 ) concentration alone ( therapeutic hypercapnia , TH ) protects against ALI in ex vivo models . We investigated whether TH would protect against ALI in an in vivo model of lung ischemia-reperfusion ( IR ) . Anesthetized open chest rabbits were ventilated ( st and ard eucapnic setting s ) , and were r and omized to TH ( FI(CO(2 ) ) 0.12 ) versus control ( FI(CO(2 ) ) 0.00 ) . Pa(CO(2 ) ) and arterial pH values achieved in the TH versus CON groups were 101 + /- 3 versus 44.4 + /- 4 mm Hg and 7.10 + /- 0.03 versus 7.37 + /- 0.03 , respectively . Following left lung ischemia and reperfusion , TH versus control was associated with preservation of lung mechanics , attenuation of protein leakage , reduction in pulmonary edema , and improved oxygenation . Indices of systemic protection included improved acid-base and lactate profile , in the absence of systemic hypoxemia . In the TH group , mean BALF TNF-alpha levels were 3.5 % of CON levels ( p < 0.01 ) , and mean 8-isoprostane levels were 30 % of CON levels ( p = 0.02 ) . Western blot analysis demonstrated reduced lung tissue nitrotyrosine in TH , indicating attenuation of tissue nitration . Finally , preliminary data suggest that TH may attenuate apoptosis following lung IR . We conclude that in the current model TH is protective versus IR lung injury and mechanisms of protection include preservation of lung mechanics , attenuation of pulmonary inflammation , and reduction of free radical mediated injury . If these findings are confirmed in additional models , TH may become a c and i date for clinical testing in critical care Mechanical ventilation with high tidal volumes ( VT ) and zero or low positive end-expiratory pressure increased mediator release to inflammatory stimuli or acute lung injury . We studied whether mechanical ventilation modifies the inflammatory responses during major thoracic or abdominal surgery . Sixty-four patients undergoing elective thoracotomy ( n = 34 ) or laparotomy ( n = 30 ) were r and omized to receive either mechanical ventilation with VT = 12 or 15 mL/kg ideal body weight , respectively , and zero end-expiratory pressure , or VT = 6 mL/kg ideal body weight with positive end-expiratory pressure of 10 cm H2O . In 62 patients who completed the study , arterial oxygena- tion was not different between groups . Tumor necrosis factor , interleukin (IL)-1 , IL-6 , IL-8 , IL-10 , and IL-12 were determined by cytometric bead array in plasma after 0 , 1 , 2 , and 3 h and in tracheal aspirates after 3 h of mechanical ventilation . Data were log-transformed and analyzed using parametric or nonparametric tests , as indicated . All plasma mediators increased more during abdominal than during thoracic surgery , although the differences were small . However , neither time course nor concentrations of pulmonary or systemic mediators differed between the two ventilatory setting s. Our data suggest that the ventilatory setting s we studied do not affect inflammatory reactions during major surgery within 3 Objective : It has been shown in a two-center study that high positive end-expiratory pressure ( PEEP ) and low tidal volume ( LTV ) improved outcome in ARDS . However , that study involved patients with underlying diseases unique to the study area , was conducted at only two centers , and enrolled a small number of patients . We similarly hypothesized that a ventilatory strategy based on PEEP above the lower inflection point of the pressure volume curve of the respiratory system ( Pflex ) set on day 1 with a low tidal volume would result in improved outcome in patients with severe and persistent acute respiratory distress syndrome ( ARDS ) . Design : R and omized , controlled clinical trial . Setting : Network of eight Spanish multidisciplinary intensive care units ( ICUs ) under the acronym of ARIES ( Acute Respiratory Insufficiency : España Study ) . Patients : All consecutive patients admitted into participating Spanish ICUs from March 1999 to March 2001 with a diagnosis of ARDS were considered for the study . If 24 hrs after meeting ARDS criteria , the Pao2/Fio2 remained ≤200 mm Hg on st and ard ventilator setting s , patients were r and omized into two groups : control and Pflex/LTV . Interventions : In the control group , tidal volume was 9–11 mL/kg of predicted body weight ( PBW ) and PEEP ≥5 cm H2O . In the Pflex/LTV group , tidal volume was 5–8 mL/kg PBW and PEEP was set on day 1 at Pflex + 2 cm H2O . In both groups , Fio2 was set to maintain arterial oxygen saturation > 90 % and Pao2 70–100 mm Hg , and respiratory rate was adjusted to maintain Paco2 between 35 and 50 mm Hg . Measurements and Main Results : The study was stopped early based on an efficacy stopping rule as described in the methods . Of 103 patients who were enrolled ( 50 control and 53 Pflex ) , eight patients ( five in control , three in Pflex ) were excluded from the final evaluation because the r and om group assignment was not performed in one center according to protocol . Main outcome measures were ICU and hospital mortality , ventilator-free days , and nonpulmonary organ dysfunction . ICU mortality ( 24 of 45 [ 53.3 % ] vs. 16 of 50 [ 32 % ] , p = .040 ) , hospital mortality ( 25 of 45 [ 55.5 % ] vs. 17 of 50 [ 34 % ] , p = .041 )  , and ventilator-free days at day 28 ( 6.02 ± 7.95 in control and 10.90 ± 9.45 in Pflex/LTV , p = .008 ) all favored Pflex/LTV . The mean difference in the number of additional organ failures postr and omization was higher in the control group ( p < .001 ) . Conclusions : A mechanical ventilation strategy with a PEEP level set on day 1 above Pflex and a low tidal volume compared with a strategy with a higher tidal volume and relatively low PEEP has a beneficial impact on outcome in patients with severe and persistent ARDS OBJECTIVE To determine the effects of different mechanical ventilation on oxygenation and shunt fraction in patient undergoing valve replacement . METHODS Thirty ASA II-III patients ( 12 males , 18 females ) , aged 25 - 56 years , undergoing valve replacement were r and omly divided into 3 groups according to the mechanical ventilation method . Anesthesia was induced with midazolam 0.1 mg/kg , fentanl 10 microg/kg , vecuronium 0.1 mg/kg , and etomi date 0.3 mg/kg . Valve replacement was performed with moderate hypothermic cardiopulmonary bypass ( CPB ) . The patients were mechanically ventilated with pure oxygen and I : E ratio 1:2 . Group A ( TV = 7 ml/kg , f=12 bpm ) , Group B ( TV=5 ml/kg , f=15 bpm ) , and Group C ( TV=7 ml/kg , f=15 bpm ) .  ECG , BP , SPO2 , and CVP were routinely monitored . Blood sample s were taken from the radial artery and pulmonary artery at 30 min after the induction of anesthesia , 10 min before CPB , and the end of operation for blood gas analysis . Respiratory index ( P(A-a ) DO2/PaO2 ) , and Qs/Qt were calculated . RESULTS There was no significant difference in age , weight , duration of operation of CPB time and aortic cross-clamping time among the 3 groups . At the end of operation , PaO2 decreased significantly , P (A-a)DO2 , RI , and Qs/Qt increased significantly in group A , while there was no significant change in group B and group C. At the end of the operation , PaCO2 was lower than the baseline value ( < 35 mmHg ) in Group A , but it was normal in Group B and group C. CONCLUSION The mechanical ventilation method of lower tidal volume and higher respiratory rate might increase the oxygenation and decrease shunt fraction and might be more suitable in patients undergoing valve replacement Objective To evaluate the effects of protective and conventional ventilation with or without positive end-expiratory pressure ( PEEP ) , on systemic tumor necrosis factor-α , interleukin-6 levels and pulmonary function during open heart surgery . Design Prospect i ve , r and omized clinical study . Setting Single university hospital . Patients and participants Forty-four patients undergoing elective coronary artery bypass grafting surgery with cardiopulmonary bypass . Interventions Patients ventilated with ( 1 ) protective tidal volumes ( 6 ml/kg , respiratory rate : 15 breaths/min , PEEP 5 cmH2O , n=15 ) group PV ; ( 2 ) conventional tidal volumes ( 10 ml/kg , respiratory rate : 9 breaths/min , PEEP 5 cmH2O , n=14 ) group CV+PEEP and ( 3 ) conventional tidal volumes ( 10 ml/kg , respiratory rate : 9 breaths/min , n=15 ) without PEEP , group CV+ZEEP . Various pulmonary parameters , systemic TNF-α and IL-6 levels were determined throughout the study . Measurements and results There were no differences among the groups regarding the systemic TNF- α and IL-6 levels . The plateau airway pressures of group PV were lower than those of groups CV+PEEP ( p=0.02 ) and CV+ZEEP ( p=0.001 ) after cardiopulmonary bypass . The shunt fraction of group PV was significantly lower than that of group CV+ZEEP 24 h after surgery ( p<0.05 ) . Oxygenation and the alveolar-arterial oxygen difference were better in both PEEP groups than in group CV+ZEEP 24 h after the operation . Conclusions We could not find any evidence that protective mechanical ventilation prevents some of the adverse effects of cardiopulmonary bypass on the lung , nor systemic cytokine levels , postoperative pulmonary function or length of hospitalization BACKGROUND Lung-protective ventilation with the use of low tidal volumes and positive end-expiratory pressure is considered best practice in the care of many critically ill patients . However , its role in anesthetized patients undergoing major surgery is not known . METHODS In this multicenter , double-blind , parallel-group trial , we r and omly assigned 400 adults at intermediate to high risk of pulmonary complications after major abdominal surgery to either nonprotective mechanical ventilation or a strategy of lung-protective ventilation . The primary outcome was a composite of major pulmonary and extrapulmonary complications occurring within the first 7 days after surgery . RESULTS The two intervention groups had similar characteristics at baseline . In the intention-to-treat analysis , the primary outcome occurred in 21 of 200 patients ( 10.5 % ) assigned to lung-protective ventilation , as compared with 55 of 200 ( 27.5 % ) assigned to nonprotective ventilation ( relative risk , 0.40 ; 95 % confidence interval [ CI ] , 0.24 to 0.68 ; P=0.001 ) . Over the 7-day postoperative period , 10 patients ( 5.0 % ) assigned to lung-protective ventilation required noninvasive ventilation or intubation for acute respiratory failure , as compared with 34 ( 17.0 % ) assigned to nonprotective ventilation ( relative risk , 0.29 ; 95 % CI , 0.14 to 0.61 ; P=0.001 ) . The length of the hospital stay was shorter among patients receiving lung-protective ventilation than among those receiving nonprotective ventilation ( mean difference , -2.45 days ; 95 % CI , -4.17 to -0.72 ; P=0.006 ) . CONCLUSIONS As compared with a practice of nonprotective mechanical ventilation , the use of a lung-protective ventilation strategy in intermediate-risk and high-risk patients undergoing major abdominal surgery was associated with improved clinical outcomes and reduced health care utilization . ( IMPROVE Clinical Trials.gov number , NCT01282996 . ) OBJECTIVE Protective lung ventilation is reported to benefit patients with acute respiratory distress syndrome . It is not known whether protective lung ventilation is also beneficial to patients undergoing single-lung ventilation for elective pulmonary resection . METHODS In an institutional review board-approved prospect i ve r and omized trial , 34 patients undergoing elective pulmonary resection requiring single-lung ventilation were enrolled . Informed consent was obtained . Patients were r and omized to 1 of 2 groups : ( 1 ) high tidal volume ( Hi-TV ) of 10 mL/kg , rate of 7 breaths/min , and zero positive end-expiratory pressure or ( 2 ) low tidal volume ( Lo-TV ) of 5 mL/kg , rate of 14 breaths/min , and 5 cmH2O positive end-expiratory pressure . Ventilator setting s were continued during both double- and single-lung ventilation .  Pulmonary functions , hemodynamics , and postoperative outcomes were recorded . RESULTS Patient demographics , operative characteristics , intraoperative hemodynamics , and postoperative pain and sedation scores were similar between the 2 groups . During most time periods , airway pressures ( peak and plateau ) were significantly higher in the Hi-TV group ; however , plateau pressures remained less than 30 cmH2O at all times for all patients . The Hi-TV group had significantly lower arterial carbon dioxide tension , less arterial carbon dioxide tension-end-tidal carbon dioxide gradient , lower alveolar dead space ratio , and higher dynamic pulmonary compliance . There were no differences in postoperative morbidity and hospital days between the 2 groups , but atelectasis scores on postoperative days 1 and 2 were lower in the Hi-TV group . CONCLUSIONS The use of Hi-TV during single-lung ventilation for pulmonary resection result ed in no increase in morbidity and was associated with less hypercarbia , less dead space ventilation , better dynamic compliance , and less postoperative atelectasis OBJECTIVE To ascertain if protective ventilation can attenuate the damaging postoperative pulmonary effects of cardiopulmonary bypass ( increases in airway pressure , decreases in lung compliance , and increases in shunt ) . DESIGN Prospect i ve , r and omized clinical trial . SETTING Single university hospital . PARTICIPANTS Twenty-five patients undergoing elective coronary artery bypass graft procedure and early extubation . INTERVENTIONS Thirteen patients received conventional mechanical ventilation ( CV ; respiratory rate , 8 breaths/min ; tidal volume , 12 mL/kg ; fraction of inspired oxygen [ FIO2 ] , 1.0 ; positive end-expiratory pressure [ PEEP ] , + 5 ) , and 12 patients received protective mechanical ventilation ( PV ; respiratory rate , 16 breaths/min ; tidal volume , 6 mL/kg ; FIO2 , 1.0 ; PEEP , + 5 ) . Perioperative anesthetic and surgical management were st and ardized . Various pulmonary parameters were determined twice perioperatively : 10 minutes after intubation and 60 minutes after arrival in the intensive care unit . MEASUREMENTS AND MAIN RESULTS The mean postoperative increase in peak airway pressure in group CV was significantly larger than the mean postoperative increase in peak airway pressure in group PV ( 7.1 v 2.4 cm H2O ; p < 0.001 ) . Group CV experienced significant postoperative increases in plateau airway pressure ( p = 0.007 ) , but group PV did not ( p = 0.644 ) . The mean postoperative decrease in dynamic lung compliance in group CV was significantly larger than the mean postoperative decrease in dynamic lung compliance in group PV ( 14.9 v 5.5 mL/cm H2O ; p = 0.002 ) . Group CV experienced significant postoperative decreases in static lung compliance ( p = 0.014 ) , but group PV did not ( p = 0.645 ) . Group CV experienced significant postoperative increases in shunt ( 15.5 % to 21.4 % ; p = 0.021 ) , but group PV did not ( 18.4 % to 21.2 % ; p = 0.265 ) . CONCLUSIONS Data indicate that protective ventilation decreases pulmonary damage caused by mechanical ventilation in normal and abnormal lungs . The results of this investigation indicate that protective ventilation may also help attenuate the postoperative pulmonary dysfunction ( increases in airway pressure , decreases in lung compliance , and increases in shunt ) commonly seen in patients after exposure to cardiopulmonary bypass OBJECTIVE To assess the feasibility and safety of thoracoscopic bulla resection under laryngeal mask anesthesia with low tidal volume high-frequency lung ventilation . METHODS Sixty patients with pulmonary bulla were r and omized into two groups ( n=30 ) to undergo video-assisted thoracoscopic surgery ( VATS ) for bulla resection with laryngeal mask anesthesia and high-frequency low tidal volume lung ventilation general anesthesia and or with intubation anesthesia and one-lung ventilation through double-lumen endotracheal intubation . RESULTS No significant differences were found in anesthesia time , surgery time , intraoperative lowest SpO2 , intraoperative highest PetCO2 , operative field , anesthetic effects , or blood loss between the two groups . The post-operative WBC and NEU% showed significantly smaller increments in the mask anesthesia group than in the intubation group , and the postoperative awake time , initial eating time , ambulation time , in-hospital stay , and drainage time were significantly shortened in the former group with also lower incidences of gastrointestinal reactions , throat discomfort and hoarseness . CONCLUSION Thoracoscopic bulla resection under laryngeal mask anesthesia with low tidal volume high-frequency lung ventilation is safe and feasible and results in better patient satisfaction and shorter in-hospital stay than procedures performed under intubation anesthesia with one-lung ventilation Video-assisted endoscopic techniques have reduced operative trauma in adult thoracic and general surgery but its application in children with congenital heart disease has been limited . We report the use of video-assisted thoracoscopic ( VAT ) technique of clipping patent ductus arteriosus ( PDA ) in children . Forty patients with PDA were divided into two groups : during VAT surgery patients in group A [ mean age=3.6 + /- 2.4 ( SD ) years ] were managed with right main stem bronchial intubation and those in the group B [ mean age=3.7 + /- 2.7 ( SD ) years ] received low tidal volume-high frequency ventilation using a Siemens 900C ventilator . The mean oxygen saturation ( SpO2 ) observed during the surgical intervention was significantly lower in group A ( 90 % ) compared to group B ( 96.8 % ) while the surgical convenience was not different . We conclude that a low tidal volume-high frequency ventilation is acceptable and safe in patients with PDA undergoing VATS To investigate whether hypercapnic acidosis protects against ventilator-induced lung injury ( VILI ) in vivo , we subjected 12 anesthetized , paralyzed rabbits to high tidal volume ventilation ( 25 cc/kg ) at 32 breaths per minute and zero positive end-expiratory pressure for 4 hours . Each rabbit was r and omized to receive either an FI(CO(2 ) ) to achieve eucapnia ( Pa(CO(2 ) ) approximately 40 mm Hg ; n = 6 ) or hypercapnic acidosis ( Pa(CO(2 ) ) 80 - 100 mm Hg ; n = 6 ) . Injury was assessed by measuring differences between the two groups ' respiratory mechanics , gas exchange , wet : dry weight , bronchoalveolar lavage fluid protein concentration and cell count , and injury score . The eucapnic group showed significantly higher plateau pressures ( 27.0 + /- 2.5 versus 20.9 + /- 3.0 ; p = 0.016 ) , change in Pa(O(2 ) ) ( 165.2 + /- 19.4 versus 77.3 + /- 87.9 mm Hg ; p = 0.02 ) , wet : dry weight ( 9.7 + /- 2.3 versus 6.6 + /- 1.8 ; p = 0.04 ) , bronchoalveolar lavage protein concentration ( 1,350 + /- 228 versus 656 + /- 511 micro g/ml ; p = 0.03 ) , cell count ( 6.86 x 10(5 ) + /- 0.18 x 10(5 ) versus 2.84 x 10(5 ) + /- 0.28 x 10(5 ) nucleated cells/ml ; p = 0.021 ) , and injury score ( 7.0 + /- 3.3 versus 0.7 + /- 0.9 ; p < 0.0001 ) . We conclude that hypercapnic acidosis is protective against VILI in this model BACKGROUND Low tidal volumes have been associated with improved outcomes in patients with established acute lung injury . The role of low tidal volume ventilation in patients without lung injury is still unresolved . We hypothesized that such a strategy in patients undergoing elective surgery would reduce ventilator-associated lung injury and that this improvement would lead to a shortened time to extubation METHODS A single-center r and omized controlled trial was undertaken in 149 patients undergoing elective cardiac surgery .  Ventilation with 6 versus 10 ml/kg tidal volume was compared . Ventilator setting s were applied immediately after anesthesia induction and continued throughout surgery and the subsequent intensive care unit stay . The primary endpoint of the study was time to extubation . Secondary endpoints included the proportion of patients extubated at 6 h and indices of lung mechanics and gas exchange as well as patient clinical outcomes . RESULTS Median ventilation time was not significantly different in the low tidal volume group ; a median ( interquartile range ) of 450 ( 264 - 1,044 ) min was achieved compared with 643 ( 417 - 1,032 ) min in the control group ( P = 0.10 ) . However , a higher proportion of patients in the low tidal volume group was free of any ventilation at 6 h : 37.3 % compared with 20.3 % in the control group ( P = 0.02 ) . In addition , fewer patients in the low tidal volume group required reintubation ( 1.3 vs. 9.5 % ; P = 0.03 ) . CONCLUSIONS Although reduction of tidal volume in mechanically ventilated patients undergoing elective cardiac surgery did not significantly shorten time to extubation , several improvements were observed in secondary outcomes . When these data are combined with a lack of observed complications , a strategy of reduced tidal volume could still be beneficial in this patient population OBJECTIVES Respiratory support for patients recovering from cardiopulmonary bypass and cardiac surgery uses large tidal volumes and a minimal level of positive end-expiratory pressure . Recent data indicate that these ventilator setting s might cause pulmonary and systemic inflammation in patients with acute lung injury . We examined the hypothesis that high tidal volumes and low levels of positive end-expiratory pressure might worsen the inflammatory response associated to cardiopulmonary bypass . METHODS Forty patients undergoing elective coronary artery bypass were r and omized to be ventilated after cardiopulmonary bypass disconnection  with high tidal volume/low positive end-expiratory pressure ( 10 - 12 mL/kg and 2 - 3 cm H2O , respectively ) or low tidal volume/high positive end-expiratory pressure ( 8 mL/kg and 10 cm H2O , respectively ) . Interleukin 6 and interleukin 8 levels were measured in the bronchoalveolar lavage fluid and plasma . Sample s were taken before sternotomy ( time 0 ) , immediately after cardiopulmonary bypass separation ( time 1 ) , and after 6 hours of mechanical ventilation ( time 2 ) . RESULTS Interleukin 6 and interleukin 8 levels in the bronchoalveolar lavage fluid and plasma significantly increased at time 1 in both groups but further increased at time 2 only in patients ventilated with high tidal volume/low positive end-expiratory pressure . Interleukin 6 and interleukin 8 levels in the bronchoalveolar lavage fluid and in the plasma at time 2 were higher with high tidal volume/low positive end-expiratory pressure than with low tidal volume/high positive end-expiratory pressure . CONCLUSION Mechanical ventilation might be a cofactor able to influence the inflammatory response after cardiac surgery BACKGROUND Ventilation with lower tidal volume improves outcome in acute respiratory distress syndrome ( ARDS ) . However , it is question able if ventilation strategy using lower tidal volumes created for patients with ARDS can be transferred to healthy patients undergoing general anesthesia . We assessed the effects of ventilation with lower tidal volumes and conventional tidal volumes on functional residual capacity ( FRC ) and Pa(O2)/FI(O2 ) ( P/F ) ratio in patients undergoing general anesthesia for upper abdominal surgery . METHODS We studied 16 patients undergoing general anesthesia for upper abdominal surgery . Patients were r and omized to ventilation with low tidal volume group ( 7 ml x kg(-1 ) predicted body weight n = 8) or conventional tidal volume group ( 10 ml x kg(-1 ) predicted body weight n = 8) . We measured FRC and P/F ratio after induction of general anesthesia and start of surgery in both groups . RESULTS There were no differences in FRC and P/F ratio between ventilation with lower tidal volume group and conventional tidal volume group ( P > 0.05 ) , but peak airway pressures with conventional tidal volume group were higher than those with lower tidal volume group only after induction of general anesthesia ( P < 0.05 ) . CONCLUSIONS Lower tidal volumes are better than conventional tidal volumes in view of airway pressure and lung protective strategy during general anesthesia Background : Alveolar fibrin deposition is a hallmark of acute lung injury , result ing from activation of coagulation and inhibition of fibrinolysis . Previous studies have shown that mechanical ventilation with high tidal volumes may aggravate lung injury in patients with sepsis and acute lung injury . The authors sought to determine the effects of mechanical ventilation on the alveolar hemostatic balance in patients without preexistent lung injury . Methods : Patients scheduled for an elective surgical procedure ( lasting ≥ 5 h ) were r and omly assigned to mechanical ventilation with either higher tidal volumes of 12 ml/kg ideal body weight and no positive end-expiratory pressure ( PEEP ) or lower tidal volumes of 6 ml/kg and 10 cm H2O PEEP . After induction of anesthesia and 5 h later bronchoalveolar lavage fluid and blood sample s were obtained , and markers of coagulation and fibrinolysis were measured . Results : In contrast to mechanical ventilation with lower tidal volumes and PEEP ( n = 21 ) , the use of higher tidal volumes without PEEP ( n = 19 ) caused activation of bronchoalveolar coagulation , as reflected by a marked increase in thrombin – antithrombin complexes , soluble tissue factor , and factor VIIa after 5 h of mechanical ventilation . Mechanical ventilation with higher tidal volumes without PEEP caused an increase in soluble thrombomodulin in lavage fluids and lower levels of bronchoalveolar activated protein C in comparison with lower tidal volumes and PEEP . Bronchoalveolar fibrinolytic activity did not change by either ventilation strategy . Conclusions : Mechanical ventilation with higher tidal volumes and no PEEP promotes procoagulant changes , which are largely prevented by the use of lower tidal volumes and PEEP
Objective Protective ventilation ( PV ) has been vali date d in patients with acute respiratory distress syndrome .
However , the effect of PV in patients undergoing major surgery is controversial .
The study aim ed to explore the beneficial effect of PV on patients undergoing a major operation by systematic review and meta- analysis .