Open Lung Approach for the Acute Respiratory Distress Syndrome: A Pilot, Randomized Controlled Trial* Effect of alveolar recruitment maneuver in early acute respiratory distress syndrome according to antiderecruitment strategy, etiological category of diffuse lung injury, and body position of the patient* A comparison of biologically variable ventilation to recruitment manoeuvres in a porcine model of acute lung injury Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome. Efficacy of positive end-expiratory pressure titration after the alveolar recruitment manoeuvre in patients with acute respiratory distress syndrome A randomised controlled trial of an open lung strategy with staircase recruitment, titrated PEEP and targeted low airway pressures in patients with acute respiratory distress syndrome Lung recruitment in patients with the acute respiratory distress syndrome. Complications From Recruitment Maneuvers in Patients With Acute Lung Injury: Secondary Analysis From the Lung Open Ventilation Study Lung recruitment manoeuvres are effective in regaining lung volume and oxygenation after open endotracheal suctioning in acute respiratory distress syndrome Driving pressure and survival in the acute respiratory distress syndrome. Ventilation strategy using low tidal volumes, recruitment maneuvers, and high positive end-expiratory pressure for acute lung injury and acute respiratory distress syndrome: a randomized controlled trial. Effects of periodic lung recruitment maneuvers on gas exchange and respiratory mechanics in mechanically ventilated acute respiratory distress syndrome (ARDS) patients High frequency oscillatory ventilation compared with conventional mechanical ventilation in adult respiratory distress syndrome: a randomized controlled trial [ISRCTN24242669] Beneficial effects of the "open lung approach" with low distending pressures in acute respiratory distress syndrome. A prospective randomized study on mechanical ventilation. [A study on the effect of recruitment maneuver imposed on extravascular lung water in patients with acute respiratory distress syndrome]. Reversibility of lung collapse and hypoxemia in early acute respiratory distress syndrome. Clinical efficacy and safety of recruitment maneuver in patients with acute respiratory distress syndrome using low tidal volume ventilation: a multicenter randomized controlled clinical trial. Recruitment Maneuvers after a Positive End-expiratory Pressure Trial Do Not Induce Sustained Effects in Early Adult Respiratory Distress Syndrome Effects of recruitment maneuvers in patients with acute lung injury and acute respiratory distress syndrome ventilated with high positive end-expiratory pressure* [Comparison of the effects of BiPAP ventilation combined with lung recruitment maneuvers and low tidal volume A/C ventilation in patients with acute respiratory distress syndrome]. Effect of a protective-ventilation strategy on mortality in the acute respiratory distress syndrome. An evaluation of a single chest physiotherapy treatment on mechanically ventilated patients with acute lung injury. [Effects of high positive end-expiratory pressure combined with recruitment maneuvers in patients with acute respiratory distress syndrome]. Comparison of Conventional Mechanical Ventilation and High‐frequency Ventilation: A Prospective, Randomized Trial in Patients with Respiratory Failure Open and Closed-circuit Endotracheal Suctioning in Acute Lung Injury: Efficiency and Effects on Gas Exchange High-frequency oscillatory ventilation for acute respiratory distress syndrome in adults: a randomized, controlled trial. Severe pandemic H1N1 2009 influenza A infection: are we ready to move on? Epidemiology, Patterns of Care, and Mortality for Patients With Acute Respiratory Distress Syndrome in Intensive Care Units in 50 Countries.
Objective : The open lung approach is a mechanical ventilation strategy involving lung recruitment and a decremental positive end-expiratory pressure trial . We compared the Acute Respiratory Distress Syndrome network protocol using low levels of positive end-expiratory pressure with open lung approach result ing in moderate to high levels of positive end-expiratory pressure for the management of established moderate/severe acute respiratory distress syndrome . Design : A prospect i ve , multicenter , pilot , r and omized controlled trial . Setting : A network of 20 multidisciplinary ICUs . Patients : Patients meeting the American-European Consensus Conference definition for acute respiratory distress syndrome were considered for the study . Interventions : At 12 - 36 hours after acute respiratory distress syndrome onset , patients were  assessed under st and ardized ventilator setting s ( FIO2≥0.5 , positive end-expiratory pressure ≥10 cm H2O ) . If Pao2/FIO2 ratio remained less than or equal to 200 mm Hg , patients were r and omized to open lung approach or Acute Respiratory Distress Syndrome network protocol . All patients were ventilated with a tidal volume of 4 to 8 ml/kg predicted body weight . Measurements and Main Results : From 1,874 screened patients with acute respiratory distress syndrome , 200 were r and omized : 99 to open lung approach and 101 to Acute Respiratory Distress Syndrome network protocol . Main outcome measures were 60-day and ICU mortalities , and ventilator-free days . Mortality at day-60 ( 29 % open lung approach vs. 33 % Acute Respiratory Distress Syndrome Network protocol , p = 0.18 , log rank test ) , ICU mortality ( 25 % open lung approach vs. 30 % Acute Respiratory Distress Syndrome network protocol , p = 0.53 Fisher ’s exact test ) , and ventilator-free days ( 8 [ 0 - 20 ] open lung approach vs. 7 [ 0 - 20 ] d Acute Respiratory Distress Syndrome network protocol , p = 0.53 Wilcoxon rank test ) were not significantly different . Airway driving pressure ( plateau pressure - positive end-expiratory pressure ) and PaO2/FIO2 improved significantly at 24 , 48 and 72 hours in patients in open lung approach compared with patients in Acute Respiratory Distress Syndrome network protocol . Barotrauma rate was similar in both groups . Conclusions : In patients with established acute respiratory distress syndrome , open lung approach improved oxygenation and driving pressure , without detrimental effects on mortality , ventilator-free days , or barotrauma . This pilot study supports the need for a large , multicenter trial using recruitment maneuvers and a decremental positive end-expiratory pressure trial in persistent acute respiratory distress syndrome Objective To assess how the level of positive end-expiratory pressure ( PEEP ) ( antiderecruitment strategy ) , etiological category of diffuse lung injury , and body position of the patient modify the effect of the alveolar recruitment maneuver ( ARM ) in acute respiratory distress syndrome ( ARDS ) . Design Prospect i ve clinical trial . Setting Medical intensive care unit at a tertiary hospital . Patients Forty-seven patients with early ARDS , including 19 patients from our preliminary study . InterventionFrom baseline ventilation at a tidal volume of 8 mL/kg and PEEP of 10 cm H2O , the ARM ( a stepwise increase in the level of PEEP up to 30 cm H2O with a concomitant decrease in the magnitude of tidal volume down to 2 mL/kg ) was given with ( ARM + PEEP , n = 20 ) or without ( ARM only , n = 19 ) subsequent increase of PEEP to 15 cm H2O . In eight other patients , PEEP was increased to 15 cm H2O without a preceding ARM ( PEEP only ) . Measurements and Results In all three groups , Pao2 was increased by the respective intervention ( all p < .05 ) . In the ARM-only group , Pao2 at 15 mins after intervention was lower than Pao2 immediate after intervention ( p = .046 ) . In the ARM + PEEP group , no such decrease in Pao2 was observed , and Pao2 at 15 , 30 , 45 , and 60 mins after intervention was higher than in the ARM-only group ( all p < .05 ) . Compared with the PEEP-only group , Pao2 of the ARM + PEEP group was higher immediately after intervention and at the later time points ( all p < .05 ) . Compared with patients with ARDS associated with direct lung injury ( pulmonary ARDS ) , patients with ARDS associated with indirect lung injury ( extrapulmonary ARDS ) showed a greater increase in Pao2 ( 27 ± 21 % vs. 130 ± 112%;p = .002 ) and a greater decrease in radiologic scores ( 1.0 ± 2.4 vs. 3.4 ± 1.5;p = .005 ) after the ARM . The increase in Pao2 induced by the ARM was greater for patients in the supine position than for patients in the prone position ( 61 ± 82 % vs. 21 ± 14%;p = .028 ) . Consequently , Pao2 immediately after the ARM was similar in the two groups of patients in different positions . Conclusions After the ARM , a sufficient level of PEEP is required as an antiderecruitment strategy . Pulmonary ARDS and extrapulmonary ARDS may be different pathophysiologic entities . An effective ARM may obviate the need for the prone position in ARDS at least in terms of oxygenation Background Biologically variable ventilation ( return of physiological variability in rate and tidal volume using a computer-controller ) was compared to control mode ventilation with and without a recruitment manoeuvre – 40 cm H2O for 40 sec performed hourly ; in a porcine oleic acid acute lung injury model . Methods We compared gas exchange , respiratory mechanics , and measured bronchoalveolar fluid for inflammatory cytokines , cell counts and surfactant function . Lung injury was scored by light microscopy . Pigs received mechanical ventilation ( FIO2 = 0.3 ; PEEP 5 cm H2O ) in control mode until PaO2 decreased to 60 mm Hg with oleic acid infusion ( PaO2/FIO2 < 200 mm Hg ) . Additional PEEP to 10 cm H2O was added after injury . Animals were r and omized to one of the 3 modes of ventilation and followed for 5 hr after injury . Results PaO2 and respiratory system compliance was significantly greater with biologically variable ventilation compared to the other 2 groups . Mean and mean peak airway pressures were also lower . There were no differences in cell counts in bronchoalveolar fluid by flow cytometry , or interleukin-8 and -10 levels between groups . Lung injury scoring revealed no difference between groups in the regions examined . No differences in surfactant function were seen between groups by capillary surfactometry . Conclusions In this porcine model of acute lung injury , various indices to measure injury or inflammation did not differ between the 3 approaches to ventilation . However , when using a low tidal volume strategy with moderate levels of PEEP , sustained improvements in arterial oxygen tension and respiratory system compliance were only seen with BVV when compared to CMV or CMV with a recruitment manoeuvre 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 Introduction In acute respiratory distress syndrome ( ARDS ) , adequate positive end-expiratory pressure ( PEEP ) may decrease ventilator-induced lung injury by minimising overinflation and cyclic recruitment-derecruitment of the lung . We evaluated whether setting the PEEP using decremental PEEP titration after an alveolar recruitment manoeuvre ( ARM ) affects the clinical outcome in patients with ARDS . Methods Fifty-seven patients with early ARDS were r and omly assigned to a group given decremental PEEP titration following ARM or a table-based PEEP ( control ) group . PEEP  and  inspired fraction of oxygen ( FiO2 )  in the control group were set according to the table-based combinations of FiO2 and PEEP of the ARDS network , by which we aim ed to achieve a PEEP level compatible with an oxygenation target . In the decremental PEEP titration group , the oxygen saturation and static compliance were monitored as the patients performed the ARM along with the extended sigh method , which is design ed to gradually apply and withdraw a high distending pressure over a prolonged period , and the decremental titration of PEEP . Results The baseline characteristics did not differ significantly between the control and decremental PEEP titration groups . Initial oxygenation improved more in the decremental PEEP titration group than in the control group . However , dynamic compliance , tidal volume and PEEP were similar in the two groups during the first week . The duration of use of paralysing or sedative agents , mechanical ventilation , stay in the intensive care unit and mortality at 28 days did not differ significantly between the decremental PEEP titration and control groups . Conclusions The daily decremental PEEP titration after ARM showed only initial oxygenation improvement compared with the table-based PEEP method . Respiratory mechanics and patient outcomes did not differ between the decremental PEEP titration and control groups . Trial registration Clinical Trials.gov identifier : IS RCT N79027921 Introduction Tidal volume and plateau pressure minimisation are the st and ard components of a protective lung ventilation strategy for patients with acute respiratory distress syndrome ( ARDS ) . Open lung strategies , including higher positive end-expiratory pressure ( PEEP ) and recruitment manoeuvres to date have not proven efficacious . This study examines the effectiveness and safety of a novel open lung strategy , which includes permissive hypercapnia , staircase recruitment manoeuvres ( SRM ) and low airway pressure with PEEP titration . Method Twenty ARDS patients were r and omised to treatment or ARDSnet control ventilation strategies . The treatment group received SRM with decremental PEEP titration and targeted plateau pressure < 30 cm H2O . Gas exchange and lung compliance were measured daily for 7 days and plasma cytokines in the first 24 hours and on days 1 , 3 , 5 and 7 ( mean ± SE ) . Duration of ventilation , ICU stay and hospital stay ( median and interquartile range ) and hospital survival were determined . Results There were significant overall differences between groups when considering plasma IL-8 and TNF-α . For plasma IL-8 , the control group was 41 % higher than the treatment group over the seven-day period ( ratio 1.41 ( 1.11 to 1.79 ) , P = 0.01 ) , while for TNF-α the control group was 20 % higher over the seven-day period ( ratio 1.20 ( 1.01 to 1.42 ) P = 0.05 ) . PaO2/FIO2 ( 204 ± 9 versus 165 ± 9 mmHg , P = 0.005 ) and static lung compliance ( 49.1 ± 2.9 versus 33.7 ± 2.7 mls/cm H2O , P < 0.001 ) were higher in the treatment group than the control group over seven days . There was no difference in duration of ventilation ( 180 ( 87 to 298 ) versus 341 ( 131 to 351 ) hrs , P = 0.13 ) , duration of ICU stay ( 9.9 ( 5.6 to 14.8 ) versus 16.0 ( 8.1 to 19.3 ) days , P = 0.19 ) and duration of hospital stay ( 17.9 ( 13.7 to 34.5 ) versus 24.7 ( 20.5 to 39.8 ) days , P = 0.16 ) between the treatment and control groups . Conclusions This open lung strategy was associated with greater amelioration in some systemic cytokines , improved oxygenation and lung compliance over seven days . A larger trial powered to examine clinical ly-meaningful outcomes is warranted . Trial registration BACKGROUND In the acute respiratory distress syndrome ( ARDS ) , positive end-expiratory pressure ( PEEP ) may decrease ventilator-induced lung injury by keeping lung regions open that otherwise would be collapsed . Since the effects of PEEP probably depend on the recruitability of lung tissue , we conducted a study to examine the relationship between the percentage of potentially recruitable lung , as indicated by computed tomography ( CT ) , and the clinical and physiological effects of PEEP . METHODS Sixty-eight patients with acute lung injury or ARDS underwent whole-lung CT during breath-holding sessions at airway pressures of 5 , 15 , and 45 cm of water . The percentage of potentially recruitable lung was defined as the proportion of lung tissue in which aeration was restored at airway pressures between 5 and 45 cm of water . RESULTS The percentage of potentially recruitable lung varied widely in the population , accounting for a mean ( + /-SD ) of 13+/-11 percent of the lung weight , and was highly correlated with the percentage of lung tissue in which aeration was maintained after the application of PEEP ( r2=0.72 , P<0.001 ) . On average , 24 percent of the lung could not be recruited . Patients with a higher percentage of potentially recruitable lung ( greater than the median value of 9 percent ) had greater total lung weights ( P<0.001 ) , poorer oxygenation ( defined as a ratio of partial pressure of arterial oxygen to fraction of inspired oxygen ) ( P<0.001 ) and respiratory-system compliance ( P=0.002 ) , higher levels of dead space ( P=0.002 ) , and higher rates of death ( P=0.02 ) than patients with a lower percentage of potentially recruitable lung . The combined physiological variables predicted , with a sensitivity of 71 percent and a specificity of 59 percent , whether a patient 's proportion of potentially recruitable lung was higher or lower than the median . CONCLUSIONS In ARDS , the percentage of potentially recruitable lung is extremely variable and is strongly associated with the response to PEEP BACKGROUND : There are limited data on the safety and efficacy of recruitment maneuvers ( RMs ) in acute lung injury ( ALI ) patients . OBJECTIVE : To evaluate the frequency , timing , and risk factors for complications from RMs in adult ALI patients . METHODS : Secondary analysis of data from a r and omized controlled trial of a lung open ventilation strategy that included sustained inflation RMs . RESULTS : Respiratory ( eg , desaturation ) and cardiovascular ( eg , hypotension ) complications from recruitment maneuvers were common ( 22 % of all patients receiving RMs ) , and the majority occurred within 7 days of enrollment . New air leak through an existing chest tube was uncommon ( < 5 % ) . As compared to patients receiving 1 or fewer RMs , the number of RMs received was associated with increased risk in both younger ( age ≤ 56 y ) and older patients ( age > 56 y ) : 2 RMs odds ratio [ OR ] 6.92 ( 95 % CI 1.70–28.2 ) , ≥ 3 RMs OR 15.4 ( 95 % CI 4.77–49.6 ) , and 2 RMs OR 5.43 ( 95 % CI 1.76–16.8 ) , ≥ 3 RMs OR 4.93 ( 95 % CI 1.78–13.7 ) , respectively . Patients with extrapulmonary ALI had decreased odds of developing complications ( OR 0.42 , 95 % CI 0.22–0.80 ) . CONCLUSIONS : Complications in adult ALI patients receiving RMs were common , but serious complications ( eg , new air leak through an existing chest tube ) were infrequent . There is a significant association between the number of RMs received and complications , even after controlling for illness severity and duration . Given their uncertain benefit in ALI patients , and the potential for complications with repeated application , the routine use of sustained inflation RMs is not justified Introduction Lung collapse is a contributory factor in the hypoxaemia that is observed after open endotracheal suctioning ( ETS ) in patients with acute lung injury and acute respiratory distress syndrome . Lung recruitment ( LR ) manoeuvres may be effective in rapidly regaining lung volume and improving oxygenation after ETS . Material s and method A prospect i ve , r and omized , controlled study was conducted in a 15-bed general intensive care unit at a university hospital . Eight consecutive mechanically ventilated patients with acute lung injury or acute respiratory distress syndrome were included . One of two suctioning procedures was performed in each patient . In the first procedure , ETS was performed followed by LR manoeuvre and reconnection to the ventilator with positive end-expiratory pressure set at 1 cmH2O above the lower inflexion point , and after 60 min another ETS ( but without LR manoeuvre ) was performed followed by reconnection to the ventilator with similar positive end-expiratory pressure ; the second procedure was the same as the first but conducted in reverse order . Before ( baseline ) and over 25 min following each ETS procedure , partial arterial oxygen tension ( PaO2 ) and end-expiratory lung volume were measured . Results After ETS , PaO2 decreased by 4.3(0.9–9.7)kPa ( median and range ; P < 0.005 ) . After LR manoeuvre , PaO2 recovered to baseline . Without LR manoeuvre , PaO2 was reduced ( P = 0.05 ) until 7 min after ETS . With LR manoeuvre end-expiratory lung volume was unchanged after ETS , whereas without LR manoeuvre end-expiratory lung volume was still reduced ( approximately 10 % ) at 5 and 15 min after ETS ( P = 0.01 ) . Discussion A LR manoeuvre immediately following ETS was , as an adjunct to positive end-expiratory pressure , effective in rapidly counteracting the deterioration in PaO2 and lung volume caused by open ETS in ventilator-treated patients with acute lung injury or acute respiratory distress syndrome BACKGROUND Mechanical-ventilation strategies that use lower end-inspiratory ( plateau ) airway pressures , lower tidal volumes ( VT ) , and higher positive end-expiratory pressures ( PEEPs ) can improve survival in patients with the acute respiratory distress syndrome ( ARDS ) , but the relative importance of each of these components is uncertain . Because respiratory-system compliance ( CRS ) is strongly related to the volume of aerated remaining functional lung during disease ( termed functional lung size ) , we hypothesized that driving pressure ( ΔP = VT/CRS ) , in which VT is intrinsically normalized to functional lung size ( instead of predicted lung size in healthy persons ) , would be an index more strongly associated with survival than VT or PEEP in patients who are not actively breathing . METHODS Using a statistical tool known as multilevel mediation analysis to analyze individual data from 3562 patients with ARDS enrolled in nine previously reported r and omized trials , we examined ΔP as an independent variable associated with survival . In the mediation analysis , we estimated the isolated effects of changes in ΔP result ing from r and omized ventilator setting s while minimizing confounding due to the baseline severity of lung disease . RESULTS Among ventilation variables , ΔP was most strongly associated with survival . A 1-SD increment in ΔP ( approximately 7 cm of water ) was associated with increased mortality ( relative risk , 1.41 ; 95 % confidence interval [ CI ] , 1.31 to 1.51 ; P<0.001 ) , even in patients receiving " protective " plateau pressures and VT ( relative risk , 1.36 ; 95 % CI , 1.17 to 1.58 ; P<0.001 ) . Individual changes in VT or PEEP after r and omization were not independently associated with survival ; they were associated only if they were among the changes that led to reductions in ΔP ( mediation effects of ΔP , P=0.004 and P=0.001 , respectively ) . CONCLUSIONS We found that ΔP was the ventilation variable that best stratified risk . Decreases in ΔP owing to changes in ventilator setting s were strongly associated with increased survival . ( Funded by Fundação de Amparo e Pesquisa do Estado de São Paulo and others . ) CONTEXT Low-tidal-volume ventilation reduces mortality in critically ill patients with acute lung injury and acute respiratory distress syndrome . Instituting additional strategies to open collapsed lung tissue may further reduce mortality . OBJECTIVE To compare an established low-tidal-volume ventilation strategy with an experimental strategy based on the original " open-lung approach , " combining low tidal volume , lung recruitment maneuvers , and high positive-end-expiratory pressure . DESIGN AND SETTING R and omized controlled trial with concealed allocation and blinded data analysis conducted between August 2000 and March 2006 in 30 intensive care units in Canada , Australia , and Saudi Arabia . PATIENTS Nine hundred eighty-three consecutive patients with acute lung injury and a ratio of arterial oxygen tension to inspired oxygen fraction not exceeding 250 . INTERVENTIONS The control strategy included target tidal volumes of 6 mL/kg of predicted body weight , plateau airway pressures not exceeding 30 cm H2O , and conventional levels of positive end-expiratory pressure ( n = 508 ) . The experimental strategy included target tidal volumes of 6 mL/kg of predicted body weight , plateau pressures not exceeding 40 cm H2O , recruitment maneuvers , and higher positive end-expiratory pressures ( n = 475 ) . MAIN OUTCOME MEASURE All-cause hospital mortality . RESULTS Eighty-five percent of the 983 study patients met criteria for acute respiratory distress syndrome at enrollment . Tidal volumes remained similar in the 2 groups , and mean positive end-expiratory pressures were 14.6 ( SD , 3.4 ) cm H2O in the experimental group vs 9.8 ( SD , 2.7 ) cm H2O among controls during the first 72 hours ( P < .001 ) . All-cause hospital mortality rates were 36.4 % and 40.4 % , respectively ( relative risk [ RR ] , 0.90 ; 95 % confidence interval [ CI ] , 0.77 - 1.05 ; P = .19 ) . Barotrauma rates were 11.2 % and 9.1 % ( RR , 1.21 ; 95 % CI , 0.83 - 1.75 ; P = .33 ) . The experimental group had lower rates of refractory hypoxemia ( 4.6 % vs 10.2 % ; RR , 0.54 ; 95 % CI , 0.34 - 0.86 ; P = .01 ) , death with refractory hypoxemia ( 4.2 % vs 8.9 % ; RR , 0.56 ; 95 % CI , 0.34 - 0.93 ; P = .03 ) , and previously defined eligible use of rescue therapies ( 5.1 % vs 9.3 % ; RR , 0.61 ; 95 % CI , 0.38 - 0.99 ; P = .045 ) . CONCLUSIONS For patients with acute lung injury and acute respiratory distress syndrome , a multifaceted protocol ized ventilation strategy design ed to recruit and open the lung result ed in no significant difference in all-cause hospital mortality or barotrauma compared with an established low-tidal-volume protocol ized ventilation strategy . This " open-lung " strategy did appear to improve secondary end points related to hypoxemia and use of rescue therapies . TRIAL REGISTRATION clinical trials.gov Identifier : NCT00182195 Objective : We wished to investigate whether volume recruitment maneuvers ( VRMs ) could improve alveolar recruitment and oxygenation in acute respiratory distress syndrome ( ARDS ) patients , ventilated at relatively low positive end-expiratory pressure ( PEEP ) . Setting : General intensive care unit ( ICU ) located in a teaching hospital . Patients : 15 PEEP responder ARDS patients undergoing continuous positive pressure ventilation ( CPPV ) with sedation and muscle paralysis . Interventions : We identified a low ( 9.4 ± 3 cmH2O ) and a high ( 16.0 ± 2 cmH2O ) level of PEEP associated with target oxygenation values . Using a custom modified mechanical ventilator , we applied in r and om order three steps lasting 30 min : ( 1 ) CPPV at the low PEEP level ( CPPVlo ) ; ( 2 ) CPPV at the high PEEP level ( CPPVhi ) ; ( 3 ) CPPV at low PEEP with the superimposition of periodic VRMs ( CPPVvrm ) . VRMs were performed twice a minute by increasing PEEP to the high level for two breaths . Each brace of two breaths was spaced 30 seconds from the preceding one . Measurements and results : We measured gas exchange , hemodynamics , respiratory mechanics , and the end expiratory lung volume ( EELV ) . Compared to CPPVlo , CPPVvrm result ed in higher PaO2 ( 117.9 ± 40.6 vs 79.4 ± 13.6 mmHg , P < 0.01 ) and EELV ( 1.50 ± 0.62 vs 1.26 ± 0.50 l , P < 0.05 ) , and in lower venous admixture ( Qva/Qt ) ( 0.42 ± 0.07 vs 0.48 ± 0.07 , P < 0.01 ) . During CPPVhi , we observed significantly higher PaO2 ( 139.3 ± 32.5 mmHg ) and lower Qva/Qt ( 0.37 ± 0.08 ) compared to CPPVlo ( P < 0.01 ) and to CPPVvrm ( P < 0.05 ) . Conclusions : VRMs can improve oxygenation and alveolar recruitment during CPPV at relatively low PEEP , but are relatively less effective than a continuous high PEEP level Introduction To compare the safety and efficacy of high frequency oscillatory ventilation ( HFOV ) with conventional mechanical ventilation ( CV ) for early intervention in adult respiratory distress syndrome ( ARDS ) , a multi-centre r and omized trial in four intensive care units was conducted . Methods Patients with ARDS were r and omized to receive either HFOV or CV .  In both treatment arms a priority was given to maintain lung volume while minimizing peak pressures . CV ventilation strategy was aim ed at reducing tidal volumes . In the HFOV group , an open lung strategy was used . Respiratory and circulatory parameters were recorded and clinical outcome was determined at 30 days of follow up . Results The study was prematurely stopped . Thirty-seven patients received HFOV and 24 patients CV  ( average APACHE II score 21 and 20 , oxygenation index 25 and 18 and duration of mechanical ventilation prior to r and omization 2.1 and 1.5 days , respectively ) . There were no statistically significant differences in survival without supplemental oxygen or on ventilator , mortality , therapy failure , or crossover . Adjustment by a priori defined baseline characteristics showed an odds ratio of 0.80 ( 95 % CI 0.22–2.97 ) for survival without oxygen or on ventilator , and an odds ratio for mortality of 1.15 ( 95 % CI 0.43–3.10 ) for HFOV compared with CV . The response of the oxygenation index ( OI ) to treatment did not differentiate between survival and death . In the HFOV group the OI response was significantly higher than in the CV group between the first and the second day . A post hoc analysis suggested that there was a relatively better treatment effect of HFOV compared with CV in patients with a higher baseline OI . Conclusion No significant differences were observed , but this trial only had power to detect major differences in survival without oxygen or on ventilator .  In patients with ARDS and higher baseline OI , however , there might be a treatment benefit of HFOV over CV . More research is needed to establish the efficacy of HFOV in the treatment of ARDS . We suggest that future studies are design ed to allow for informative analysis in patients with higher OI Alveolar overdistention and cyclic reopening of collapsed alveoli have been implicated in the lung damage found in animals su bmi tted to  artificial ventilation  . To test whether these phenomena are impairing the recovery of patients with acute respiratory distress syndrome ( ARDS ) su bmi tted to conventional mechanical ventilation ( MV ) , we evaluated the impact of a new ventilatory strategy directed at minimizing " cyclic parenchymal stretch . " After receiving pre-established levels of hemodynamic , infectious , and general care , 28 patients with early ARDS were r and omly assigned to receive either MV based on a new approach ( NA , consisting of maintenance of end-expiratory pressures above the lower inflection point of the P x V curve , VT < 6 ml/kg , peak pressures < 40 cm H2O , permissive hypercapnia , and stepwise utilization of pressure-limited modes ) or a conventional approach ( C = conventional volume-cycled ventilation , VT = 12 ml/kg , minimum PEEP guided by FIO2 and hemodynamics and normal PaCO2 levels ) . Fifteen patients were selected to receive NA , exhibiting a better evolution of the PaO2/FIO2 ratio ( p < 0.0001 ) and of compliance ( p = 0.0018 ) , requiring shorter periods under FIO2 > 50 % ( p = 0.001 ) and a lower FIO2 at the day of death ( p = 0.0002 ) . After correcting for baseline imbalances in APACHE II , we observed a higher weaning rate in NA ( p = 0.014 ) but not a significantly improved survival ( overall mortality : 5/15 in NA versus 7/13 in C , p = 0.45 ) . We concluded that the NA ventilatory strategy can markedly improve the lung function  in patients with ARDS , increasing the chances of early weaning and lung recovery during mechanical ventilation OBJECTIVE To investigate the possible effects of recruitment maneuver ( RM ) imposing on extravascular lung water ( EVLW ) in patients with acute respiratory distress syndrome ( ARDS ) . METHODS Twenty patients with ARDS who were eligible for the study were r and omized to two groups , one group of which received regular therapy+RM ( RM group ) , and to the other group only regular therapy was given ( control group ) . Mechanical ventilation of all the patients was performed on the principles of lung protective ventilation . RM was carried out in bi-level positive airway passage ( BIPAP ) mode , and repeated every 8 hours per day until on the 7th day or before weaning of mechanical ventilation . The treatment was same between the two groups except RM . Baseline data and the influencing factors of EVLW were all recorded , which included everyday EVLW , extravascular lung water index ( EVLWI ) after RM , respiratory mechanics , oxygenation parameters , central venous pressure ( CVP ) , plasma colloid osmotic pressure ( COP ) , dosage of corticosteroid and adrenergic drugs , 24-hour net fluid balance . RESULTS EVLW and EVLWI in RM and control group showed a tendency of decrease with passage of time , but the difference between both groups had no statistical significance ( all P>0.05 ) . The comparisons between the influencing factors of the groups , consisting of CVP , COP , noradrenaline and hydrocortisone , had no significant difference either ( all P>0.05 ) . Dopamine dosage in RM group on the 4th day was smaller than that of control group ( P<0.05 ) . Net fluid balance in RM group on the 7th day was negative , whereas it was positive in control group ( P<0.05 ) . Mean airway pressure [ Pmean , RM group ( 18.8+/-3.2 ) cm H(2)O ( 1 cm H(2)O=0.098 kPa ) vs. control group ( 16.6+/-3.9 ) cm H(2)O ] and lung quasi-static compliance [ Cstat , RM group ( 36.5+/-14.5 ) ml/cm H(2)O vs. control group ( 29.3+/-12.0 ) ml/cm H(2)O ] in RM group were higher than those in control group ( both P<0.05 ) . Cstat on the 5th day was higher than that on the 2nd and 3rd day in RM group ( both P<0.05 ) . But oxygenation index ( PaO(2)/FiO(2 ) ) showed no distinct difference between the groups ( all P>0.05 ) . CONCLUSION RM for the patients with ARDS can merely improve lung mechanics without obvious effect on EVLW . Neither of the influencing factors involved in the study has impact on emergence and clearance of EVLW RATIONALE The hypothesis that lung collapse is detrimental during the acute respiratory distress syndrome is still debatable . One of the difficulties is the lack of an efficient maneuver to minimize it . OBJECTIVES To test if a bedside recruitment strategy , capable of reversing hypoxemia and collapse in > 95 % of lung units , is clinical ly applicable in early acute respiratory distress syndrome . METHODS Prospect i ve assessment of a stepwise maximum-recruitment strategy using multislice computed tomography and continuous blood-gas hemodynamic monitoring . MEASUREMENTS AND MAIN RESULTS Twenty-six patients received sequential increments in inspiratory airway pressures , in 5 cm H(2)O steps , until the detection of Pa(O(2 ) ) + Pa(CO(2 ) ) > or= 400 mm Hg . Whenever this primary target was not met , despite inspiratory pressures reaching 60 cm H(2)O , the maneuver was considered incomplete . If there was hemodynamic deterioration or barotrauma , the maneuver was to be interrupted . Late assessment of recruitment efficacy was performed by computed tomography ( 9 patients ) or by online continuous monitoring in the intensive care unit ( 15 patients ) up to 6 h. It was possible to open the lung and to keep the lung open in the majority ( 24/26 ) of patients , at the expense of transient hemodynamic effects and hypercapnia but without major clinical consequences . No barotrauma directly associated with the maneuver was detected . There was a strong and inverse relationship between arterial oxygenation and percentage of collapsed lung mass ( R = - 0.91 ; p < 0.0001 ) . CONCLUSIONS It is often possible to reverse hypoxemia and fully recruit the lung in early acute respiratory distress syndrome . Due to transient side effects , the required maneuver still awaits further evaluation before routine clinical application BACKGROUND The recruitment maneuver ( RM ) has been shown to improve oxygenation in some patients with acute respiratory distress syndrome . But there is a lack of st and ardization and lack of clinical studies to prove the improvement on clinical outcome . We conducted this study to evaluate the clinical efficacy and safety of the RM in patients with acute respiratory distress syndrome ( ARDS ) using low tidal volume ventilation . METHODS We r and omly assigned 110 patients with ARDS from 14 Chinese intensive care units ( ICUs ) at the tertiary teaching hospitals . Patients with PaO2 ≤ 200 mmHg at FiO2 1.0 and PEEP ≥ 10 cmH2O were included in the study . Patients were r and omized into two groups : control group and RM group . The tidal volume was set to 6 - 8 ml per kilogram of predicted body weight ( PBW ) in both groups . RM was performed by continuous positive airway pressure ( CPAP ) of 40 cmH2O maintained for 40 seconds . RMs was conducted every eight hours for the first five days , or stopped within five days if the patient reached the weaning st and ard . RESULTS One hundred and ten patients had completed the requirements for the primary study goals , 55 from the RM group and 55 control patients . Baseline characteristics remained similar in the two groups . In the RM group the PaO2/FiO2 was significantly increased compared to baseline at 120 minutes after RM on day one and day two ( P = 0.007 and P = 0.001 ) . There were no significant differences between the RM and control group in hospital mortality ( 41.8 % vs. 56.4 % , P = 0.13 ) , 28-day mortality ( 29.1 % vs. 43.6 % , P = 0.11 ) and ventilator-free days at day 28 ( 10.8 ± 10.1 vs. 7.4 ± 10.0 , P = 0.08 ) . ICU mortality ( 32.7 % vs. 52.7 % , P = 0.03 ) , the rate of survival with unassisted breathing for at least 48 consecutive hours at day 28 ( 58.2 % vs. 36.2 % , P = 0.02 ) , and nonpulmonary organ failure-free days at day 28 ( 17.4 ± 11.1 vs. 13.0 ± 12.0 , P = 0.03 ) favored the RM group . There was no significant difference in mean blood pressure and heart rate before RM and at 30 , 60 , 120 minutes after RM . There was no incidence of barotraumas . CONCLUSIONS RM was safe and useful for improving oxygenation in patients with ARDS who were ventilated with a low tidal volume , with a beneficial impact on their clinical outcome Background : Recruitment maneuvers performed in early adult respiratory distress syndrome remain a matter of dispute in patients ventilated with low tidal volumes and high levels of positive end-expiratory pressure ( PEEP ) . In this prospect i ve , r and omized controlled study the authors evaluated the impact of recruitment maneuvers after a PEEP trial on oxygenation and venous admixture ( Qs/Qt ) in patients with early extrapulmonary adult respiratory distress syndrome . Methods : After a PEEP trial 30 consecutive patients ventilated with low tidal volumes and high levels of PEEP were r and omly assigned to either undergo a recruitment maneuver or not . Data were recorded at baseline , 3 min after the recruitment maneuver , and 30 min after baseline . Recruitment maneuvers were performed with a sustained inflation of 50 cm H2O maintained for 30 s. Results : Compared with baseline the ratio of the arterial oxygen partial pressure to the fraction of inspired oxygen ( Pao2/Fio2 ) and Qs/Qt improved significantly at 3 min after the recruitment maneuver ( Pao2/Fio2 , 139 ± 46 mm Hg versus 246 ± 111 mm Hg , P < 0.001 ; Qs/Qt , 30.8 ± 5.8 % versus 21.5 ± 9.7 % , P < 0.005 ) , but baseline values were reached again within 30 min . No significant differences in Pao2/Fio2 and Qs/Qt were detected between the recruitment maneuver group and the control group at baseline and after 30 min ( recruitment maneuver group [ n = 15 ] : Pao2/Fio2 , 139 ± 46 mm Hg versus 138 ± 39 mm Hg ; Qs/Qt , 30.8 ± 5.8 % versus 29.2 ± 7.4 % ; control group : [ n = 15 ] : Pao2/Fio2 , 145 ± 33 mm Hg versus 155 ± 52 mm Hg ; Qs/Qt , 30.2 ± 8.5 % versus 28.1 ± 5.4 % ) . Conclusion : In patients with early extrapulmonary adult respiratory distress syndrome who underwent a PEEP trial , recruitment maneuvers failed to induce a sustained improvement of oxygenation and venous admixture Objective Positive end-expiratory pressure ( PEEP ) and recruitment maneuvers ( RMs ) may partially reverse atelectasis and reduce ventilation-associated lung injury . The purpose s of this study were to assess a ) magnitude and duration of RM effects on arterial oxygenation and on requirements for oxygenation support ( Fio2/PEEP ) in patients with acute lung injury and acute respiratory distress syndrome ( ALI/ARDS ) receiving ventilation with low tidal volumes and high levels of PEEP ; and b ) frequency of adverse respiratory and circulatory events attributable to RMs . Design Prospect i ve , r and omized , crossover study . Setting Thirty-four intensive care units at 19 hospitals . Patients Seventy-two patients with early ALI/ARDS . Baseline PEEP and Fio2 were 13.8 ± 3.0 cm H2O and 0.39 ± 0.10 , respectively ( mean ± sd ) . Interventions We conducted RMs by applying continuous positive airway pressure of 35–40 cm H2O for 30 secs. We conducted sham RMs on alternate days . We monitored oxyhemoglobin saturation by pulse oximetry ( SpO2 ) , Fio2/PEEP , blood pressure , and heart rate for 8 hrs after RMs and sham RMs . We examined chest radiographs for barotrauma . Measurements and Main Results Responses to RMs were variable . Greatest increments from baseline SpO2 within 10 mins after RMs were larger than after sham RMs ( 1.7 ± 0.2 vs. 0.6 ± 0.3 % , mean ± sem , p < .01 ) . Systolic blood pressure decreased more within 10 mins after RMs ( 9.4 ± 1.1 vs. 3.1 ± 1.1 mm Hg , p < .01 ) . Changes in Fio2/PEEP requirements were not significantly different at any time after RMs vs. sham RMs . Barotrauma was apparent on first radiographs after one RM and one sham RM . Conclusions In ALI/ARDS patients receiving mechanical ventilation with low tidal volumes and high PEEP , short-term effects of RMs as conducted in this study are variable . Beneficial effects on gas exchange in responders appear to be of brief duration . More information is needed to determine the role of recruitment maneuvers in the management of ALI/ARDS OBJECTIVE To compare the effects of BiPAP ventilation combined with lung recruitment maneuvers ( LRM ) with low tidal volume A/C ventilation in patients with acute respiratory distress syndrome ( ARDS ) . METHODS A prospect i ve , r and omized comparison of BiPAP mechanical ventilation combined with lung recruitment maneuvers ( test group ) with low tidal volume A/C ventilation ( control group ) was conducted in 28 patients with ARDS .  FiO2/PaO2 ratio , respiratory system compliance ( Cs ) , central venous pressure ( CVP ) , duration of ventilation support were recorded at 0 h , 48 h and 72 h separately . The ventilation associated lung injury and mortality at 28 d were also recorded . RESULTS The FiO2/PaO2 ratio were ( 298+/-16 ) and ( 309+/-16 ) cm H2O , Cs were ( 38.4+/-2.2 ) and ( 42.0+/-1.3 ) ml/cm H2O , CVP were ( 13.8+/-0.8 ) and ( 11.6+/-0.7 ) cm H2O in the test group at 48 h and 72 h separately . In the control group , FiO2/PaO2 ratio were ( 212+/-12 ) and ( 246+/-17 ) cm H2O , Cs were ( 29.5+/-1.3 ) and ( 29.0+/-1.0 ) ml/cm H2O , CVP were 18.6+/-1.1 and ( 16.8+/-1.0 ) cm H2O . The results were better in the test group as compared with the control group ( t=10.03 - 29.68 , all P<0.01 ) . The duration of ventilation support in the test group was shorter than the control group [ ( 14+/-3 ) d vs ( 19+/-3 ) d , t=4.80 , P<0.01 ] . The mortality in 28 d and ventilation associated lung injury were similar in the two groups . CONCLUSION The results show that combination of LRM with BiPAP mode ventilation , as compared with the control group , contributes to improved FiO2/PaO2 ratio , pulmonary compliance , stable hemodynamic and shorter duration of ventilation support in patients with ARDS BACKGROUND In patients with the acute respiratory distress syndrome , massive alveolar collapse and cyclic lung reopening and overdistention during mechanical ventilation may perpetuate alveolar injury . We determined whether a ventilatory strategy design ed to minimize such lung injuries could reduce not only pulmonary complications but also mortality at 28 days in patients with the acute respiratory distress syndrome . METHODS We r and omly assigned 53 patients with early acute respiratory distress syndrome ( including 28 described previously ) , all of whom were receiving identical hemodynamic and general support , to conventional or protective mechanical ventilation . Conventional ventilation was based on the strategy of maintaining the lowest positive end-expiratory pressure ( PEEP ) for acceptable oxygenation , with a tidal volume of 12 ml per kilogram of body weight and normal arterial carbon dioxide levels ( 35 to 38 mm Hg ) . Protective ventilation involved end-expiratory pressures above the lower inflection point on the static pressure-volume curve , a tidal volume of less than 6 ml per kilogram , driving pressures of less than 20 cm of water above the PEEP value , permissive hypercapnia , and preferential use of pressure-limited ventilatory modes . RESULTS After 28 days , 11 of 29 patients ( 38 percent ) in the protective-ventilation group had died , as compared with 17 of 24 ( 71 percent ) in the conventional-ventilation group ( P<0.001 ) . The rates of weaning from mechanical ventilation were 66 percent in the protective-ventilation group and 29 percent in the conventional-ventilation group ( P=0.005 ) : the rates of clinical barotrauma were 7 percent and 42 percent , respectively ( P=0.02 ) , despite the use of higher PEEP and mean airway pressures in the protective-ventilation group . The difference in survival to hospital discharge was not significant ; 13 of 29 patients ( 45 percent ) in the protective-ventilation group died in the hospital , as compared with 17 of 24 in the conventional-ventilation group ( 71 percent , P=0.37 ) . CONCLUSIONS As compared with conventional ventilation , the protective strategy was associated with improved survival at 28 days , a higher rate of weaning from mechanical ventilation , and a lower rate of barotrauma in patients with the acute respiratory distress syndrome .  Protective ventilation was not associated with a higher rate of survival to hospital discharge BACKGROUND AND PURPOSE Acute lung injury is a lung pathology that presents frequently on the intensive care unit . Chest physiotherapy , in the form of endotracheal suction , alternate side-lying and manual hyperinflation , is usually given to patients with this condition with the intention of removing retained pulmonary secretions and recruiting collapsed distal lung units . Despite this common practice there is insufficient research on the effects of chest physiotherapy in patients with acute lung injury being ventilated mechanically . The aim of the present study was to further underst and ing of the effects of three modes of treatment in chest physiotherapy in an acute lung injury patient group . METHOD This r and omized , controlled trial investigated all mechanically ventilated patients with acute lung injury admitted to the adult intensive care unit at Guy 's and St Thomas ' NHS Trust between August 1996 and July 1997 , who matched the inclusion criteria . Patients were r and omized into one of three treatment groups : Group 1 ( suctioned only ) ; Group 2 ( positioned and suctioned ) ; and Group 3 ( positioned , manually hyperinflated and suctioned ) . Baseline and 10 , 30 and 60 minutes ' post-treatment data were recorded for dynamic pulmonary compliance , arterial blood gases and haemodynamic variables . Results were analysed by use of an SPSS software package with a repeated- measures analysis of variance ( ANOVA ) . RESULTS Eighteen patients fitted the inclusion criteria . Significant changes were observed in both PaCO2 ( p = 0.026 ) and dynamic compliance ( p = 0.019 ) over time for all three groups . The arterial oxygen to fraction of inspired oxygen ratio ( PaO2:FiO2 ) did not alter significantly in any of the groups . With respect to other oxygenation parameters , mixed venous oxygen saturation ( SvO2 ) showed a significant difference between the groups . Heart rate ( HR ) and systemic blood pressure ( BP ) showed statistically significant , but not clinical ly significant differences over time . CONCLUSIONS Patients with acute lung injury are notably complex to nurse and may require protracted physiotherapy intervention , which may take many forms . As de-recruitment was the single most important event that occurred in the present study population , a prescriptive chest physiotherapy approach to treating mechanically ventilated patients with acute lung should be question ed and adapted accordingly OBJECTIVE To investigate the clinical effects and safety degree of high positive end-expiratory pressure ( PEEP ) combined with lung recruitment maneuver ( RM ) in patients with acute respiratory distress syndrome ( ARDS ) . METHODS Thirty-eight patients in medical intensive care unit ( MICU ) of Affiliated Hospital of Guiyang Medical College suffering from ARDS admitted from June 2008 to May 2010 were enrolled in the study . With the envelope method they were r and omized into RM group and non-RM group , with n=19 in each group . All patients received protective ventilation : pressure support ventilation ( PSV ) with plateau pressure limited at 30 cm H(2)O ( 1 cm H(2)O=0.098 kPa ) or lower . PEEP was set at the minimum level with fraction of inspired oxygen ( FiO(2 ) ) < 0.60 and partial pressure of arterial oxygen ( PaO(2 ) ) kept between 60 and 80 mm Hg ( 1 mm Hg=0.133 kPa ) . RM was conducted by regulating FiO(2 ) to 1.00 , support pressure to 0 , PEEP increased to 40 cm H(2)O and maintained for 30 seconds before lowering , and this maneuver was repeated every 8 hours for a total of 5 days . Base status , ventilation parameters , blood gas analysis and vital signs were obtained at baseline and for the next 5 days . Oxygenation status and lung injury indexes were compared between RM group and non-RM group , the adverse effects of RM and incidence of barotrauma were recorded . RESULTS ¹ There were no significant differences of base status and ventilation parameters between RM group and non-RM group . ²PaO(2 ) and oxygenation index ( PaO(2)/FiO(2 ) ) were both increased in RM group and non-RM group , but the values were higher in RM group [ PaO(2)(mm Hg ) 2 days : 85.8±21.3 vs. 73.5±18.7 , 3 days : 88.6±22.8 vs. 74.3±19.8 , 4 days : 98.8±30.7 vs. 79.3±19.3 , 5 days : 105.5±29.4 vs. 84.4±13.8 ; PaO(2)/FiO(2 ) ( mm Hg ) 4 days : 221.8±103.5 vs. 160.3±51.4 , 5 days : 239.6±69.0 vs. 176.8±45.5 , all P<0.05 ] . ³ Hydrogen peroxide ( H(2)O(2 ) ) and interleukin-6 ( IL-6 ) concentration in exhaled breath condensate ( EBC ) decreased in both groups but lower in RM group with significant difference [ 5 days H(2)O(2 ) ( μmol/L ) : 0.04±0.02 vs. 0.10±0.03 ; IL-6 ( ng/L ) : 4.12±2.09 vs. 9.26±3.47 , both P<0.05 ] . ( 4 ) Barotrauma and arrhythmia did not occur in both groups . No significant changes in heart rate were found during RM . Central venous pressure and mean arterial pressure remained unchanged after RM . CONCLUSION High level PEEP combined with RM can improve gas exchange and oxygenation , decrease ventilator associated lung injury ( VALI ) . RM was safe and had good tolerance , no hypoxemia , barotrauma and hemodynamic instability were observed Acute respiratory failure ( ARF ) following trauma or sepsis has a mortality rate of 50 % to 85 % . The mainstays of treatment are mechanical ventilation and positive end-expiratory pressure ( PEEP ) . In the past decade , many reports have cl aim ed superiority of high frequency ventilation ( HFV ) in the treatment of ARF . We structured a prospect i ve r and omized trial of HFV versus conventional mechanical ventilation ( CMV ) in the treatment of acute respiratory failure . All patients admitted to the Surgical Intensive Care Unit ( SICU ) were eligible for the study . On admission patients identified for being at risk of developing acute respiratory failure were r and omized to receive either HFV or CMV . Patients were treated to the same therapeutic endpoint ( pH greater than 7.35 , PaCO2 35 to 45 torr , PaO2/FIO2 greater than 225 ) . Daily ventilatory support , fluid and drug requirements , and cardiopulmonary variables were recorded . One hundred thirteen patients were entered into the study . Of these , 100 completed the study ( HFV n = 52 , CMV n = 48 ) and 60 developed acute respiratory failure  ( HFV n = 32 , CMV n = 28 ) . Patients on HFV reached the therapeutic endpoint at a lower level of continuous positive airway pressure and mean airway pressure ; however there were no differences in mortality , SICU days , hospital days , incidence of barotrauma , number of blood gases , or cardiovascular interventions . This report suggests that HFV offers no concrete advantages over CMV when applied in a prospect i ve fashion for the treatment of acute respiratory failure Background : Closed-circuit endotracheal suctioning ( CES ) is advocated for preventing hypoxemia caused by the loss of lung volume result ing from open endotracheal suctioning ( OES ) . However , the efficiency of CES and OES on tracheal secretion removal has never been compared in patients with acute lung injury . The authors design ed a two-part study aim ed at comparing gas exchange and efficiency between OES and CES performed at two levels of negative pressure . Methods : Among 18 patients with acute lung injury , 9 underwent CES and OES at 3-h intervals in a r and om order using a negative pressure of −200 mmHg . Nine other patients underwent CES twice using two levels of negative pressure ( −200 and −400 mmHg ) applied in a r and om order . After each CES , a recruitment maneuver was performed using 20 consecutive hyperinflations . Tracheal aspirates were weighed after each suctioning procedure . Arterial blood gases were continuously recorded using an intravascular sensor . Results : Open endotracheal suctioning induced a significant 18 % decrease in arterial oxygen tension ( Pao2 ) ( range , + 13 to −71 % ) and an 8 % increase in arterial carbon dioxide tension ( Paco2 ) ( range , −2 to + 16 % ) that persisted 15 min after the end of the procedure . CES using −200 cm H2O did not change Pao2 , but tracheal aspirate mass was lower compared with OES ( 0.6 ± 1.0 vs. 3.2 ± 5.1 g ; P = 0.03 ) . Increasing negative pressure to −400 cm H2O during CES did not change Pao2 but increased the tracheal aspirate mass ( 1.7 ± 1.6 vs. 1.0 ± 1.3 g ; P = 0.02 ) . Conclusions : Closed-circuit endotracheal suctioning followed by a recruitment maneuver prevents hypoxemia result ing from OES but decreases secretion removal . Increasing suctioning pressure enhances suctioning efficiency without impairing gas exchange Observational studies of high-frequency oscillatory ventilation in adults with the acute respiratory distress syndrome have demonstrated improvements in oxygenation . We design ed a multicenter , r and omized , controlled trial comparing the safety and effectiveness of high-frequency oscillatory ventilation with conventional ventilation in adults with acute respiratory distress syndrome ; 148 adults with acute respiratory distress syndrome ( Pa(O2)/fraction of inspired oxygen < or= 200 mm Hg on 10 or more cm H2O positive end-expiratory pressure ) were r and omized to high-frequency oscillatory ventilation  ( n = 75 ) or conventional ventilation ( n = 73 ) . Applied mean airway pressure was significantly higher in the high-frequency oscillation group compared with the conventional ventilation group throughout the first 72 hours ( p = 0.0001 ) . The high-frequency oscillation group showed early ( less than 16 hours ) improvement in Pa(O2)/fraction of inspired oxygen compared with the conventional ventilation group ( p = 0.008 ) ; however , this difference did not persist beyond 24 hours . Oxygenation index decreased similarly over the first 72 hours in both groups . Thirty-day mortality was 37 % in the high-frequency oscillation group and was 52 % in the conventional ventilation group ( p = 0.102 ) . The percentage of patients alive without mechanical ventilation at Day 30 was 36 % and 31 % in the high-frequency oscillation and conventional ventilation groups , respectively ( p = 0.686 ) . There were no significant differences in hemodynamic variables , oxygenation failure , ventilation failure , barotraumas , or mucus plugging between treatment groups . We conclude that high-frequency oscillation is a safe and effective mode of ventilation for the treatment of acute respiratory distress syndrome in adults The 2009 H1N1 influenza A p and emic virus is a new subtype of influenza affecting humans , which contains segments of genes from swine , bird and human influenza viruses in a combination that has never been observed before . New viruses are often the result of a re-assortment of genes from two other ones . This AH1N109 virus is derived by a combination of two pre-existing swine influenza viruses , although whether the novel virus first emerged in humans or swine remains unknown . The virus was first identified as the cause of an outbreak of respiratory illness in Mexico in March 2009 , and during the following month severe cases of pneumonia preceded by influenza-like illness appeared in Mexico and the USA . In few weeks , the virus spread throughout the world result ing in an influenza p and emic despite implementation of public health control measures . The World Health Organization ( WHO ) raised the level of influenza p and emic alert from phase 5 to phase 6 in June 2009 . Recently , the 10th of August 2010 the WHO announced that the H1N1 influenza virus has moved into the post-p and emic period . During the p and emic period , the WHO reported millions of cases in more than 214 countries and at least 18 449 documented deaths . However , localized outbreaks of various magnitudes are likely to continue and the full impact of this p and emic remains unpredictable . The virus is highly infectious due to lack of background immunity ( except for the elderly age group who may have some cross-protective immunity ) , but the disease is mild in the majority of patients , and the overall case fatality rate is lower than that of seasonal influenza . According to the latest WHO statistics , the virus has killed more than 18 000 people , which represents only approximately 5 % of the annual influenza deaths . In this issue of Respirology , Martin-Loeches et al. describe the clinical characteristics of the first 131 fatal cases admitted in 144 intensive care units ( ICU ) during the initial winter wave of the p and emic influenza A infection in Spain . Their findings agree with previously published reports of severe viral pneumonia affecting patients younger than the expected age and healthy ( almost 25 % of the patients did not present with any risk factors on admission ) , which could be explained by an abnormal immune response . This finding led to promising lines of investigation . It has been recently published that severe p and emic H1N109 Influenza A infection with respiratory involvement is characterized by an early secretion of Th17 and Th1 cytokines , usually associated with cell mediated immunity . Moreover , To KK et al. reported a slower control of viral load and immunodysregulation when comparing patients with mild versus severe presentation . Martin-Loeches and colleagues identify another important issue that was the recommendation to avoid Non Invasive Ventilation ( NIV ) in patients with viral pneumonia , due to the high failure rate . Recently , the European Respiratory Society and the European Society of Intensive Care Medicine have agreed that NIV is not recommended as an alternative to invasive ventilation in patients infected by p and emic H1N109 Influenza A. Early and appropriate administration of antimicrobial therapy has been recommended by multiple observational studies to improve the care of patients with pneumonia . Surprisingly , only half of the patients in the study by Martin-Loeches et al. received empirical antiviral therapy and with late administration in spite of huge campaigns conducted by the Spanish National Health System to alert the medical staff of the p and emic wave and its proper management . This represents the difficulties in real life to adopt a new treatment and the challenges related to broad implementation of appropriate practice s. Early therapy induces a rapid decline in viral shedding , which may lead to a better outcome for these patients . In addition , the authors reported 18 % co-infected fatal cases with bacterial pathogens similar to the initial reports of Centers for Disease Control from USA at the beginning of the p and emia . However , Martin-Loeches et al. reported a 15 % mortality rate in their study cohort , very similar to reports from Australia and New Zeal and ( 17 % and 14 % , respectively ) , and considerably lower than the mortality rate reported by PerezPadilla et al. in Mexico ( 38 % ) . Unfortunately , Martin-Loeches and collaborators did not report autopsy data , which may have contribute to the underst and ing of the viral changes linked to the fatal cases . Although the p and emic was global , there were some interesting differences between Northern and Southern Hemisphere . It is crucial to underst and that the p and emic in the Northern Hemisphere took place in a different context , with more time to be prepared , vaccines more available prospect ively IMPORTANCE Limited information exists about the epidemiology , recognition , management , and outcomes of patients with the acute respiratory distress syndrome ( ARDS ) . OBJECTIVES To evaluate intensive care unit ( ICU ) incidence and outcome of ARDS and to assess clinician recognition , ventilation management , and use of adjuncts-for example prone positioning-in routine clinical practice for patients fulfilling the ARDS Berlin Definition . DESIGN , SETTING , AND PARTICIPANTS The Large Observational Study to Underst and the Global Impact of Severe Acute Respiratory Failure ( LUNG SAFE ) was an international , multicenter , prospect i ve cohort study of patients undergoing invasive or noninvasive ventilation  , conducted during 4 consecutive weeks in the winter of 2014 in a convenience sample of 459 ICUs from 50 countries across 5 continents . EXPOSURES Acute respiratory distress syndrome . MAIN OUTCOMES AND MEASURES The primary outcome was ICU incidence of ARDS . Secondary outcomes included assessment of clinician recognition of ARDS , the application of ventilatory management , the use of adjunctive interventions in routine clinical practice , and clinical outcomes from ARDS . RESULTS Of 29,144 patients admitted to participating ICUs , 3022 ( 10.4 % ) fulfilled ARDS criteria . Of these , 2377 patients developed ARDS in the first 48 hours and whose respiratory failure was managed with  invasive mechanical ventilation . The period prevalence of mild ARDS was 30.0 % ( 95 % CI , 28.2%-31.9 % ) ; of moderate ARDS , 46.6 % ( 95 % CI , 44.5%-48.6 % ) ; and of severe ARDS , 23.4 % ( 95 % CI , 21.7%-25.2 % ) . ARDS represented 0.42 cases per ICU bed over 4 weeks and represented 10.4 % ( 95 % CI , 10.0%-10.7 % ) of ICU admissions and 23.4 % of patients requiring mechanical ventilation . Clinical recognition of ARDS ranged from 51.3 % ( 95 % CI , 47.5%-55.0 % ) in mild to 78.5 % ( 95 % CI , 74.8%-81.8 % ) in severe ARDS . Less than two-thirds of patients with ARDS received a tidal volume 8 of mL/kg or less of predicted body weight . Plateau pressure was measured in 40.1 % ( 95 % CI , 38.2 - 42.1 ) , whereas 82.6 % ( 95 % CI , 81.0%-84.1 % ) received a positive end-expository pressure ( PEEP ) of less than 12 cm H2O . Prone positioning was used in 16.3 % ( 95 % CI , 13.7%-19.2 % ) of patients with severe ARDS . Clinician recognition of ARDS was associated with higher PEEP , greater use of neuromuscular blockade , and prone positioning . Hospital mortality was 34.9 % ( 95 % CI , 31.4%-38.5 % ) for those with mild , 40.3 % ( 95 % CI , 37.4%-43.3 % ) for those with moderate , and 46.1 % ( 95 % CI , 41.9%-50.4 % ) for those with severe ARDS . CONCLUSIONS AND RELEVANCE Among ICUs in 50 countries , the period prevalence of ARDS was 10.4 % of ICU admissions . This syndrome appeared to be underrecognized and undertreated and associated with a high mortality rate . These findings indicate the potential for improvement in the management of patients with ARDS . TRIAL REGISTRATION clinical trials.gov Identifier : NCT02010073
BACKGROUND Recruitment manoeuvres involve transient elevations in airway pressure applied during mechanical ventilation to open ( ' recruit ' ) collapsed lung units and increase the number of alveoli participating in tidal ventilation .
Recruitment manoeuvres are often used to treat patients in intensive care who have acute respiratory distress syndrome ( ARDS ) , but the effect of this treatment on clinical outcomes has not been well established .
This systematic review is an up date of a Cochrane review originally published in 2009 .
OBJECTIVES Our primary objective was to determine the effects of  recruitment manoeuvres  on mortality in adults with acute respiratory distress syndrome .
Our secondary objective was to determine , in the same population , the effects of  recruitment manoeuvres  on oxygenation and adverse events ( e.g. rate of barotrauma ) .