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* Lung computed tomography during a lung recruitment maneuver in patients with acute lung injury Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome. Cytokine release following recruitment maneuvers. Sigh in supine and prone position during acute respiratory distress syndrome. Do lung recruitment maneuvers decrease gastric mucosal perfusion? Lung recruitment in patients with the acute respiratory distress syndrome. Safety and efficacy of a sustained inflation for alveolar recruitment in adults with respiratory failure Effects of periodic lung recruitment maneuvers on gas exchange and respiratory mechanics in mechanically ventilated acute respiratory distress syndrome (ARDS) patients A high positive end-expiratory pressure, low tidal volume ventilatory strategy improves outcome in persistent acute respiratory distress syndrome: A randomized, controlled trial* Influence of Gas Composition on Recurrence of Atelectasis after a Reexpansion Maneuver during General Anesthesia Effects of a Sigh on the Respiratory Mechanical Properties in Ali Patients Recruitment maneuver and high positive end-expiratory pressure improve hypoxemia in patients after pulmonary thromboendarterectomy for chronic pulmonary thromboembolism* Incidence and outcomes of acute lung injury. 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* Effects of a single-lung recruitment maneuver on the systemic release of inflammatory mediators Effect of a protective-ventilation strategy on mortality in the acute respiratory distress syndrome. Effects of sustained inflation and postinflation positive end-expiratory pressure in acute respiratory distress syndrome: Focusing on pulmonary and extrapulmonary forms* Recruitment maneuver: Does it promote bacterial translocation?* Hemodynamic and respiratory changes during lung recruitment and descending optimal positive end-expiratory pressure titration in patients with acute respiratory distress syndrome. Mechanistic scheme and effect of “extended sigh” as a recruitment maneuver in patients with acute respiratory distress syndrome: A preliminary study Recruitment maneuvers during prone positioning in patients with acute respiratory distress syndrome Characteristics and outcomes in adult patients receiving mechanical ventilation: a 28-day international study. Influence of low tidal volumes on gas exchange in acute respiratory distress syndrome and the role of recruitment maneuvers.
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 Objective To assess the acute effect of a lung recruitment maneuver ( LRM ) on lung morphology in patients with acute lung injury ( ALI ) or acute respiratory distress syndrome ( ARDS ) . Patients Ten patients with ALI/ARDS on mechanical ventilation . Design Prospect i ve clinical study . Setting Computed tomography ( CT ) scan facility in a teaching hospital . Interventions An LRM performed by stepwise increases in positive end-expiratory pressure ( PEEP ) of up to 30–40 cmH2O . Lung basal CT sections were taken at end-expiration ( patients 1 to 5 ) , and at end-expiration and end-inspiration ( patients 6 to10 ) . Arterial blood gases and static compliance ( Cst ) were measured before , during and after the LRM . Measurements and main results Poorly aerated and non-aerated tissue at PEEP 10 cmH2O accounted for 60.0±29.1 % of lung parenchyma , while only 1.1±1.8 % was hyperinflated . Increasing PEEP to 20 and 30 cmH2O , compared to PEEP 10 cmH2O , decreased poorly aerated and non-aerated tissue by 16.2±28.0 % and 33.4±13.8 % , respectively ( p<0.05 ) . This was associated with an increase in PaO2 and a decrease in total static compliance . Inspiration increased alveolar recruitment at all PEEP levels . Hyperinflated tissue increased up to 2.9±4.0 % with PEEP 30 cmH2O , and to a lesser degree with inspiration . No barotrauma or severe hypotension occurred . Conclusions Lung recruitment maneuvers improve oxygenation by exp and ing collapsed alveoli without inducing too much hyperinflation in ALI/ARDS patients .  An LRM during the CT scan gives morphologic and functional information that could be useful in setting ventilatory parameters 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 BACKGROUND There are reports of rigors and /or clinical deterioration following recruitment maneuvers ( RMs ) , leading us to question whether the use of sustained high-pressure inflation could lead to release of inflammatory mediators . METHODS Prospect i ve cohort study of 26 patients with ARDS receiving mechanical ventilation . A single RM was performed during which the mean airway pressure was increased to 40 cm H2O and held constant for a period of 30 s. The concentration of nine cytokines ( interleukin [IL]-1 , IL-6 , IL-8 , IL-10 , tumor necrosis factor [TNF]-alpha , Fas lig and , vascular endothelial growth factor , TNF receptor 1 , TNF receptor 2 ) was measured longitudinally at three time points : prior to initiation of the RM , 5 min after the RM , and 60 min after the RM . RESULTS RMs were tolerated well from a hemodynamic perspective . Oxygenation improved as reflected by an increased Pao2/fraction of inspired oxygen ( Fio2 ) ratio from 140+/-49 at baseline to 190+/-78 ( mean+/-SD ) at 5 min after the RM ( p=0.01 ) . At 60 min , the increase in Pao2/Fio2 ratio , to 172+/-76 , was no longer significant ( p=0.1 ) . There were no important changes in the levels of any of the measured cytokines at 5 min or 60 min following RM as compared with the baseline levels . CONCLUSIONS The results of our study demonstrate that recruitment maneuvers are well tolerated in patients with ARDS . Our data suggest no major hemodynamic or immunologic evidence of deterioration within the first hour of RM . In particular , cytokines , previously related to worsening lung injury and distal organ failure in patients with ARDS , are not elevated by use of an RM . Registered at : www . clinical trials.gov as NCT00127491 Interventions aim ed at recruiting the lung of patients with acute respiratory distress syndrome ( ARDS ) are not uniformly effective . Because the prone position increases homogeneity of inflation of the lung , we reasoned that it might enhance its potential for recruitment . We ventilated 10 patients with early ARDS ( PaO2/FIO2 , 121 + /- 46 mm Hg ; positive end-expiratory pressure , 14 + /- 3 cm H2O ) in supine and prone , with and without the addition of three consecutive " sighs " per minute to recruit the lung . Inspired oxygen fraction , positive end-expiratory pressure , and minute ventilation were kept constant . Sighs increased PaO2 in both supine and prone ( p < 0.01 ) . The highest values of PaO2 ( 192 + /- 41 mm Hg ) and end-expiratory lung volume ( 1840 + /- 790 ml ) occurred with the addition of sighs in prone and remained significantly elevated 1 hour after discontinuation of the sighs . The increase in PaO2 associated with the sighs , both in supine and prone , correlated linearly with the respective increase of end-expiratory lung volume ( r = 0.82 , p < 0.001 ) . We conclude that adding a recruitment maneuver such as cyclical sighs during ventilation in the prone position may provide optimal lung recruitment in the early stage of ARDS Objective To evaluate effects of lung recruitment maneuvers on gastric mucosal perfusion , systemic circulation , and lung mechanics in patients with acute lung injury . Design Prospect i ve observational clinical study . Setting General intensive care unit of university hospital . Patients and participants Fourteen patients with acute lung injury ( ten in the main study group and four in a validation group ) . Interventions Three 2-min-long recruitment maneuvers ( RM ) with transient increases in mean airway pressure to 35 cmH2O ( RM1 and RM2 ) and 44 cmH2O ( RM3 ) . Measurements and results Measurements of systemic hemodynamics , gastric mucosal perfusion ( laser Doppler flowmetry ) , and lung mechanics were performed immediately before , at the end of , and 3 min after each RM . Cardiac index decreased during all RMs while mean arterial pressure decreased only during RM3 . Gastric mucosal perfusion was not significantly changed during any of the RMs . When comparing values obtained before the first RM with values after the third RM there was a significant decrease in cardiac index ( P=0.043 ) and a non-significant ( P=0.051 ) decrease in gastric mucosal perfusion . There were no significant changes in systemic oxygenation or lung mechanics after three RMs , even though four patients showed marked transient increases in systemic oxygenation during RMs . Conclusions In this study of ten patients there were no significant changes in gastric mucosal perfusion during lung recruitment maneuvers . There was , however , a trend towards gradual decreases in gastric mucosal perfusion 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 Objective : To assess the safety and efficacy of a sustained inflation , used as a lung volume recruitment maneuver in ventilated patients with hypoxemic respiratory failure.¶ Design : Prospect i ve data collection as part of a quality assurance program following introduction of a lung volume recruitment guideline in the intensive care unit.¶ Setting : Academic medical-surgical critical care unit.¶ Patients : Hypoxemic patients with bilateral pulmonary infiltrates . Patients with chronic obstructive pulmonary disease , pulmonary barotrauma and hemodynamic instability were excluded.¶ Interventions : A sustained inflation using a pressure of 30 to 45 cmH2O was applied for 20 s. The pressure was determined as the lesser of 45 cmH2O or the peak pressure while ventilated at a tidal volume of 12 ml/kg . Intra-arterial blood pressure and pulse oximetry were monitored continuously.¶ Measurements and results : Significant improvement in oxygenation occurred in the majority of patients within 10 min . The mean oxygen saturation improved from 86.9 ± 5.5 to 94.3 ± 2.3 % ( p < 0.01 ) . No significant adverse effects were noted : hypotension and mild oxygen desaturation occurred in some patients during the 20-s inflation , reversing rapidly after inflation was terminated . No barotrauma occurred.¶ Conclusions : A sustained inflation is a safe , clinical ly applicable method of lung volume recruitment which improves oxygenation in selected patients and may have a role in ventilatory management 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 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 Background Atelectasis , an important cause of impaired gas exchange during general anesthesia , may be eliminated by a vital capacity maneuver . However , it is not clear whether such a maneuver will have a sustained effect . The aim of this study was to determine the impact of gas composition on reappearance of atelectasis and impairment of gas exchange after a vital capacity maneuver . Methods A consecutive sample of 12 adults with healthy lungs who were scheduled for elective surgery were studied . Thirty minutes after induction of anesthesia with fentanyl and propofol , the lungs were hyperinflated manually up to an airway pressure of 40 cmH2 O. FI sub O2 was either kept at 0.4 ( group 1 , n = 6 ) or changed to 1.0 ( group 2 , n = 6 ) during the recruitment maneuver .  Atelectasis was assessed by computed tomography . The amount of dense areas was measured at end-expiration in a transverse plane at the base of the lungs . The ventilation-perfusion distributions ( V with dot A/Q with dot ) were estimated with the multiple inert gas elimination technique . The static compliance of the total respiratory system ( Crs ) was measured with the flow interruption technique . Results In group 1 ( FIO2 = 0.4 ) , the recruitment maneuver virtually eliminated atelectasis for at least 40 min , reduced shunt ( V with dot A/Q with dot < 0.005 ) , and increased at the same time the relative perfusion to poorly ventilated lung units ( 0.005 < V with dot A/Q with dot < 0.1 ; mean values are given ) . The arterial oxygen tension ( PaO2 ) increased from 137 mmHg ( 18.3 kPa ) to 163 mmHg ( 21.7 kPa ; before and 40 min after recruitment , respectively ; P = 0.028 ) . In contrast to these findings , atelectasis recurred within 5 min after recruitment in group 2 ( FIO2 = 1.0 ) . Comparing the values before and 40 min after recruitment , all parameters of V with dot A/Q with dot were unchanged . In both groups , Crs increased from 57.1/55.0 ml * symbol * cmH2 O sup -1 ( group 1/group 2 ) before to 70.1/67.4 ml * symbol * cmH2 O sup -1 after the recruitment maneuver . Crs showed as low decrease thereafter ( 40 min after recruitment : 61.4/60.0 ml * symbol * cmH2 O sup -1 ) , with no difference between the two groups . Conclusions The composition of inspiratory gas plays an important role in the recurrence of collapse of previously reexp and ed atelectatic lung tissue during general anesthesia in patients with healthy lungs . The reason for the instability of these lung units remains to be established . The change in the amount of atelectasis and shunt appears to be independent of the change in the compliance of the respiratory system Objectives . The application of sighs during baseline ventilation was found to improve alveolar recruitment and oxygenation in patients with acute respiratory distress syndrome ( ARDS ) . The present investigation evaluates if respiratory mechanics can be modified by a sigh . Methods . Ten consecutive patients with acute lung injury ( ALI ) admitted to the University Hospital Intensive Care Unit the were studied during mechanical ventilation . Three sighs were administered to se date d-paralyzed patients during the measurement period . Respiratory mechanics were studied in regular breaths immediately before and after a sigh provided that a steady-state had been reached and by the airway pressure-time curve profile to evaluate the lung recruitment . Viscoelastic constants ( elastic , resistive , and time ) , as well as elastance and resistances , were determined by the single breath method . Arterial blood gases were also determined pre- and post-sigh . Results : Elastic and resistive components of viscoelasticity decreased after a sigh ( 20 and 21 % , respectively ) . As a result , the pressure required to overcome viscoelasticity and mechanical inhomogeneities also decreased in these patients ( 17 % ) . The mechanical changes were associated with alterations in PaO2 . Conclusions The sigh is useful to diminish viscoelastic impedance in ALI patients , thus allowing a smaller inflation pressure . Under the present experimental conditions it seems that viscoelastic mechanical alterations precede their elastic and resistive counterparts Objectives : To investigate the effects of a recruitment maneuver and high positive end-expiratory pressure ( PEEP ) on oxygenation and hemodynamics in hypoxemic patients with pulmonary hypertension after pulmonary thromboendarterectomy for chronic pulmonary thromboembolism . Design : Prospect i ve , observational , clinical study . Setting : A surgical intensive care unit in a national heart institute . Patients : Fourteen consecutively admitted patients who developed acute lung injury ( Pao2 < 300 torr at Fio2 1.0 ) and pulmonary hypertension ( mean pulmonary artery pressure > 25 mm Hg ) after pulmonary thromboendarterectomy for chronic pulmonary thromboembolism . Interventions : The recruitment maneuver was an increase of PEEP to 30 cm H2O in one step for 1 min at Fio2 1.0 . The level of pressure control ventilation during the recruitment maneuver was the same as before the maneuver . Subsequently , PEEP was decreased in 15-min intervals from 15 to 10 , 5 , and 0 cm H2O . Measurements and Main Results : Hemodynamics and respiratory variables were analyzed before and during the recruitment maneuver and at each PEEP level . At Fio2 1.0 , Pao2 increased from 240 ± 62 torr to 470 ± 83 torr at 15 cm H2O of PEEP and 469 ± 75 torr at 10 cm H2O of PEEP after the recruitment maneuver ( p < .001 ) . At 15 cm H2O of PEEP , cardiac index decreased ( from 2.7 ± 0.6 at baseline to 2.2 ± 0.3 L·min−1·m−2 , p < .01 ) and mean blood pressure decreased ( from 86 ± 8 at baseline to 74 ± 11 mm Hg , p < .05 ) , but they returned to the baseline levels at 10 cm H2O of PEEP ( 2.5 ± 0.4 L·min−1·m−2 and 83 ± 9 mm Hg ) . There were no differences in mean pulmonary artery pressure at different levels of PEEP . Conclusions : In hypoxemic patients with pulmonary hypertension after pulmonary thromboendarterectomy for chronic pulmonary thromboembolism , oxygenation was improved by the recruitment maneuver followed by high PEEP . However , hemodynamics were transiently suppressed and overall oxygen delivery did not change BACKGROUND Acute lung injury is a critical illness syndrome consisting of acute hypoxemic respiratory failure with bilateral pulmonary infiltrates that are not attributed to left atrial hypertension . Despite recent advances in our underst and ing of the mechanism and treatment of acute lung injury , its incidence and outcomes in the United States have been unclear . METHODS We conducted a prospect i ve , population -based , cohort study in 21 hospitals in and around King County , Washington , from April 1999 through July 2000 , using a vali date d screening protocol to identify patients who met the consensus criteria for acute lung injury . RESULTS A total of 1113 King County residents undergoing mechanical ventilation met the criteria for acute lung injury and were 15 years of age or older . On the basis of this figure , the crude incidence of acute lung injury was 78.9 per 100,000 person-years and the age-adjusted incidence was 86.2 per 100,000 person-years . The in-hospital mortality rate was 38.5 percent . The incidence of acute lung injury increased with age from 16 per 100,000 person-years for those 15 through 19 years of age to 306 per 100,000 person-years for those 75 through 84 years of age . Mortality increased with age from 24 percent for patients 15 through 19 years of age to 60 percent for patients 85 years of age or older ( P<0.001 ) . We estimate that each year in the United States there are 190,600 cases of acute lung injury , which are associated with 74,500 deaths and 3.6 million hospital days . CONCLUSIONS Acute lung injury has a substantial impact on public health , with an incidence in the United States that is considerably higher than previous reports have suggested 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 study the hypothesis , that systemic levels of pro-inflammatory and anti-inflammatory cytokines may be affected by a single recruitment maneuver in mechanically ventilated patients . Design Prospect i ve , interventional clinical trial . Setting Intensive care unit of a university hospital . Patients Sixteen mechanically ventilated patients with clinical and radiological signs of atelectasis . Interventions A single recruitment maneuver ( RM ) was performed by elevating the airway pressure to 40 cmH2O for 7 s. Measurements and main results Plasmatic concentrations of interleukin (IL)-1β , IL-6 , IL-8 , IL-10 , IL-12p70 and tumor necrosis factor ( TNF-α ) , arterial blood gases and hemodynamic parameters were measured immediately before and 5–360 min after the RM . The RM caused a minor , nevertheless significant improvement of oxygenation ( p = 0.02 ) and carbon dioxide elimination ( p = 0.006 ) as well as a moderate drop of the mean arterial pressure ( p = 0.025 ) . In contrast , plasma concentrations remained unaffected by the RM in all six mediators measured . Conclusion A single inflation with an airway pressure of 40 cmH2O for 7 s improved gas exchange only slightly and did not modify systemic levels of inflammatory mediators in mechanically ventilated patients with radiological evidence of atelectasis 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 Objective To investigate whether the response to sustained inflation and postinflation positive end-expiratory pressure varies between acute respiratory distress syndrome with pulmonary ( ARDSp ) and extrapulmonary origin ( ARDSexp ) . Design Prospect i ve clinical study . Setting Multidisciplinary intensive care unit in a university hospital . Patients A total of 11 patients with ARDSp and 13 patients with ARDSexp . Interventions A 7 ml/kg tidal volume , 12–15 breaths/min respiratory rate , and an inspiratory/expiratory ratio of 1:2 was used during baseline ventilation . Positive end-expiratory pressure levels were set according to the decision of the primary physician . Sustained inflation was performed by 45 cm H2O continuous positive airway pressure for 30 secs. Postinflation positive end-expiratory pressure was titrated decrementally , starting from a level of 20 cm H2O to keep the peripheral oxygen saturation between 92 % and 95 % . Fio2 was decreased , and baseline tidal volume , respiratory rate , inspiratory/expiratory ratio were maintained unchanged throughout the study period . Measurements and Main Results Blood gas , airway pressure , and hemodynamic measurements were performed at the following time points : at baseline and at 15 mins , 1 hr , 4 hrs , and 6 hrs after sustained inflation . After sustained inflation , the Pao2/Fio2 ratio improved in all of the patients both in ARDSp and ARDSexp . However , the Pao2/Fio2 ratio increased to > 200 in four ARDSp patients ( 36 % ) and in seven ARDSexp patients ( 54 % ) . In two of those ARDSp patients , the Pao2/Fio2 ratio was found to be < 200 , whereas none of the ARDSexp patients revealed Pao2/Fio2 ratios of < 200 at the 6-hr measurement . Postinflation positive end-expiratory pressure levels were set at 16.7 ± 2.3 cm H2O in ARDSexp and 15.6 ± 2.5 cm H2O in ARDSp . The change in Pao2/Fio2 ratios was found statistically significant in patients with ARDSexp ( p = .0001 ) and with ARDSp ( p = .008 ) . Respiratory system compliance increased in ARDSexp patients ( p = .02 ) , whereas the change in ARDSp was not statistically significant . Conclusions Sustained inflation followed by high levels of postinflation positive end-expiratory pressure provided an increase in respiratory system compliance in ARDSexp ; however , arterial oxygenation improved in both ARDS forms Objective High peak airway opening pressures ( Pao ) are used routinely during recruitment maneuvers to open collapsed lung units . High peak Pao , however , can cause lung injury as evidence d by translocation of intratracheally inoculated bacteria . In this study we explored whether recruitment maneuvers that used high Pao could cause translocation of the intratracheally inoculated Pseudomonas aeruginosa from the alveoli into the systemic circulation . Design Prospect i ve , r and omized , animal study . Setting Experimental animal care laboratory . Subjects Eighteen male Sprague Dawley rats . Interventions Rats were anesthetized , tracheostomized , and ventilated with 14 cm H2O peak Pao and 0 cm H2O positive end-expiratory pressure ( PEEP ) in pressure-controlled ventilation ( frequency , 30 bpm ; inspiratory/expiratory ratio , 1:2 ; Fio2 , 1 ) . Intratracheal inoculation of 500 & mgr;L of saline containing 1 × 105 colony forming units/mL P. aeruginosa was performed before r and omization into three groups ( n = 6 in each ) : a low-pressure group ( 14 cm H2O peak Pao , 0 cm H2O PEEP ) , a high-pressure group ( 45 cm H2O peak Pao , 0 cm H2O PEEP ) , and a recruitment maneuver group ( 14 cm H2O peak Pao , 0 cm H2O PEEP , and a recruitment maneuver sustained inflation of 45 cm H2O continuous positive airway pressure for 30 secs every 15 mins ) . Blood sample s for blood gas analysis were obtained before intratracheal instillation of bacteria and at the end of the experimental protocol ( 2 hrs ) . Blood cultures were obtained before and after bacterial instillation at 30-min intervals during the experiment . Blood sample s were cultured directly in sheep blood , MacConkey , and Iso-Sensitest agars and were observed on the second day . Bacteremia was defined as the presence of one or more colonies of P. aeruginosa in 1 mL of blood . Measurements and Main Results The blood cultures were positive for P. aeruginosa in only six rats in the high-pressure group and remained negative throughout the study period in the low-pressure and recruitment maneuver groups . Oxygenation deteriorated in all groups after intratracheal instillation of bacteria . In the high-pressure group , oxygenation decreased from 417 ± 67 mm Hg to 79 ± 20 mm Hg ( p = .004 ) , whereas in the low-pressure and recruitment maneuver groups Pao2 decreased from 410 ± 98 mm Hg and 383 ± 78 mm Hg to 287 ± 105 mm Hg ( p = .031 ) and 249 ± 59 mm Hg ( p = .11 ) , respectively . Conclusion Intermittent recruitment maneuvers applied as a sustained inflation superimposed on low-pressure ventilation with 0 cm H2O PEEP did not cause translocation of intratracheally inoculated P. aeruginosa OBJECTIVES To investigate respiratory and hemodynamic changes during lung recruitment and descending optimal positive end-expiratory pressure ( PEEP ) titration . DESIGN Prospect i ve auto-control clinical trial . SETTING Adult general intensive care unit in a university hospital . PATIENTS Eighteen patients with acute respiratory distress syndrome . INTERVENTIONS Following baseline measurements ( T0 ) , PEEP was set at 26 cm H2O and lung recruitment was performed ( 40/40-maneuver ) . Then tidal volume was set at 4 mL/kg ( T26R ) and PEEP was lowered by 2 cm H2O in every 4 mins . Optimal PEEP was defined at 2 cm H2O above the PEEP where Pao2 dropped by > 10 % . After setting the optimal PEEP , the 40/40-maneuver was repeated and tidal volume set at 6 mL/kg ( T(end ) ) . MEASUREMENTS AND MAIN RESULTS Arterial blood gas analysis was done every 4 mins and hemodynamic measurements every 8 mins until T(end ) , then in 30 ( T30 ) and 60 ( T60 ) mins . The Pao2 increased from T0 to T(end ) ( 203 + /- 108 vs. 322 + /- 101 mm Hg , p < .001 ) , but the extravascular lung water ( EVLW ) did not change significantly . Cardiac index ( CI ) and the intrathoracic blood volume ( ITBV ) decreased from T0 to T26R ( CI , 3.90 + /- 1.04 vs. 3.62 + /- 0.91 L/min/m2 , p < .05 ; ITBVI , 832 + /- 205 vs. 795 + /- 188 m/m2 , p < .05 ) . There was a positive correlation between CI and ITBVI ( r = .699 , p < .01 ) , a negative correlation between CI and central venous pressure ( r = -.294 , p < .01 ) , and no correlation between CI and mean arterial pressure ( MAP ) . CONCLUSIONS Following lung recruitment and descending optimal PEEP titration , the Pao2 improves significantly , without any change in the EVLW up to 1 hr . This suggests a decrease in atelectasis as a result of recruitment rather than a reduction of EVLW . There is a significant change in CI during the maneuver , but neither central venous pressure , heart rate , nor MAP can reflect these changes Objective To devise a new form of sigh ( “ extended sigh ” ) capable of providing a sufficient recruiting pressure × time , and to test it as a recruitment maneuver in patients with acute respiratory distress syndrome . Design Prospect i ve uncontrolled clinical trial . Setting Medical intensive care unit of a university-affiliated hospital . Patients Twenty consecutive patients diagnosed with acute respiratory distress syndrome ( 18 men , 2 women , age 59 ± 10 yrs ) . Interventions From baseline setting s of tidal volume ( Vt ) 8 mL/kg and positive end-expiratory pressure ( PEEP ) 10 cm H2O on volume control mode with the high pressure limit at 40 cm H2O , the Vt-PEEP values were changed to 6–15 , 4–20 , and 2–25 , each step being 30 secs ( inflation phase ) . After Vt-PEEP 2–25 , the mode was switched to continuous positive airway pressure of 30 cm H2O for a duration of 30 secs ( pause ) , after which the baseline setting was resumed following the reverse sequence of inflation ( deflation phase ) . This extended sigh was performed twice with 1 min of baseline ventilation between . Measurements and Results Airway pressures and hemodynamic parameters were traced at each step during the extended sigh . Arterial blood gases and physiologic parameters were determined before the extended sigh ( pre-extended sigh ) , at 5 mins after two extended sighs ( post-extended sigh ) , and then every 15 mins for 1 hr . In our average patient , the recruiting pressure × time of the inflation phase was estimated to be 32.8–35.4 cm H2O × 90 secs. Compared with the inflation phase , inspiratory pause pressure of the deflation phase was lower at Vt-PEEP 6–15 ( 28.9 ± 2.7 cm H2O vs. 27.3 ± 2.8 cm H2O ) and 4–20 ( 31.8 ± 2.9 cm H2O vs. 31.1 ± 2.9 cm H2O ; both p < .05 ) . Compared with pre-extended sigh , Pao2 ( 81.5 ± 15.3 mm Hg vs. 104.8 ± 25.0 mm Hg;p < .001 ) and static respiratory compliance both increased post-extended sigh ( 27.9 ± 7.9 mL/cm H2O vs. 30.2 ± 9.7 mL/cm H2O;p = .009 ) . Improvement in these parameters was sustained above pre-extended sigh for the duration of the study . Major hemodynamic or respiratory complications were not noted during the study . Conclusion We present a new form of sigh ( i.e. , extended sigh ) capable of achieving an augmented recruiting pressure × time through a prolonged inflation on a gradually increased end-expiratory pressure . In view of the sustained effect and absence of major complications in our patients , extended sigh could be a useful recruitment maneuver in acute respiratory distress syndrome Objective : To evaluate the interaction of recruitment maneuvers and prone positioning on gas exchange and venous admixture in patients with early extrapulmonary acute respiratory distress syndrome ventilated with high levels of positive end-expiratory pressure . We hypothesized that a sustained inflation performed after 6 hrs of prone positioning would induce sustained improvement in oxygenation ( Pao2/Fio2 ) and venous admixture . Design : Prospect i ve , interventional study . Setting : Tertiary care , postoperative intensive care unit . Patients : Fifteen patients with early extrapulmonary acute respiratory distress syndrome . Interventions : After 6 hrs of prone positioning , a sustained inflation was performed with 50 cm H2O maintained for 30 secs. Data were recorded in supine position , after 6 hrs of prone positioning , at 3 , 30 , and 180 mins following the sustained inflation . Measurements and Main Results : A response to prone positioning was observed in nine of 15 patients leading to an improvement of Pao2/Fio2 ( 147 ± 37 torr vs. 225 ± 77 torr , p = .005 ) and venous admixture ( 35.4 ± 8.3 % vs. 28.9 ± 9.8 % , p = .001 ) . Six patients did not respond to prone positioning . Following the sustained inflation , the responders to prone positioning showed a further increase of Pao2/Fio2 and decrease of venous admixture at 3 mins ( Pao2/Fio2 , 225 ± 77 torr vs. 368 ± 90 torr , p = .018 ; venous admixture , 28.9 ± 9.8 % vs. 18.9 ± 6.7 % , p = .05 ) . In all six nonresponders to prone positioning , an improvement of Pao2/Fio2 and venous admixture occurred at 3 mins following the sustained inflation ( 128 ± 18 torr vs. 277 ± 59 torr , p = .03 ; venous admixture , 34.2 ± 6.0 % vs. 23.8 ± 6.3 % , p = .05 ) . The beneficial effects of the sustained inflation remained significantly elevated over 3 hrs in responders and nonresponders to prone positioning . Conclusion : In patients with early extrapulmonary acute respiratory distress syndrome , a sustained inflation performed after 6 hrs of prone positioning induced further and sustained improvement of oxygenation and venous admixture in both responders and nonresponders to prone positioning CONTEXT The outcome of patients receiving mechanical ventilation for particular indications has been studied , but the outcome in a large number of unselected , heterogeneous patients has not been reported . OBJECTIVE To determine the survival of patients receiving mechanical ventilation  and the relative importance of factors influencing survival . DESIGN , SETTING , AND SUBJECTS Prospect i ve cohort of consecutive adult patients admitted to 361 intensive care units who received mechanical ventilation for more than 12 hours between March 1 , 1998 , and March 31 , 1998 . Data were collected on each patient at initiation of mechanical ventilation and daily throughout the course of mechanical ventilation for up to 28 days . MAIN OUTCOME MEASURE All-cause mortality during intensive care unit stay . RESULTS Of the 15 757 patients admitted , a total of 5183 ( 33 % ) received mechanical ventilation  for a mean ( SD ) duration of 5.9 ( 7.2 ) days . The mean ( SD ) length of stay in the intensive care unit was 11.2 ( 13.7 ) days . Overall mortality rate in the intensive care unit was 30.7 % ( 1590 patients ) for the entire population , 52 % ( 120 ) in patients who received ventilation because of acute respiratory distress syndrome , and 22 % ( 115 ) in patients who received ventilation for an exacerbation of chronic obstructive pulmonary disease . Survival of unselected patients receiving mechanical ventilation for more than 12 hours was 69 % . The main conditions independently associated with increased mortality were ( 1 ) factors present at the start of mechanical ventilation ( odds ratio [ OR ] , 2.98 ; 95 % confidence interval [ CI ] , 2.44 - 3.63 ; P<.001 for coma ) , ( 2 ) factors related to patient management ( OR , 3.67 ; 95 % CI , 2.02 - 6.66 ; P<.001 for plateau airway pressure > 35 cm H(2)O ) , and ( 3 ) developments occurring over the course of mechanical ventilation ( OR , 8.71 ; 95 % CI , 5.44 - 13.94 ; P<.001 for ratio of PaO(2 ) to fraction of inspired oxygen < 100 ) . CONCLUSION Survival among mechanically ventilated patients depends not only on the factors present at the start of mechanical ventilation , but also on the development of complications and patient management in the intensive care unit UNLABELLED BACKGROUND Use of a low tidal volume ( V(T ) ) strategy in the treatment of acute respiratory distress syndrome can lead to a decrease in oxygenation . This study evaluated the safety and efficacy of a recruitment maneuver ( RM ) in this setting . METHODS Twelve patients with acute respiratory distress syndrome were studied within 48 hours of diagnosis . Baseline gas exchange , hemodynamics , and respiratory mechanics were determined and patients were placed on a V(T ) of 6 mL/kg . Measurements were repeated and an RM of 30 cm H20 for 40 seconds was performed . Measurements were repeated at 30 minutes and 2 hours post-RM . RESULTS Decreasing V(T ) result ed in a decrease in arterial oxygenation ( from 91 + /- 9 mm Hg to 75 + /- 9 mm Hg , p < 0.01 ) , an increase in shunt ( from 19 + /- 3.7 % to 23 + /- 5 % , p < 0.01 ) , and a decrease in lung compliance ( from 37 mL/cm H2O to 33 mL/cm H2O , < 0.05 ) . At 30 minutes post-RM , oxygenation improved to 99 + /- 16 mm Hg , shunt decreased to 17 + /- 3 % , and lung compliance improved to 39 mL/cm H2O ( p < 0.05 ) . Two hours later , oxygenation fell ( 86 + /- 12 mm Hg ) , shunt increased ( 20 + /- 3 % ) , and compliance diminished ( 36 mL/cm H2O ) . There were no hemodynamic or barotraumatic complications . CONCLUSION An RM transiently improves gas exchange during low V(T)ventilation . RMs are well tolerated and no hemodynamic consequences were seen
RATIONALE There are conflicting data regarding the safety and efficacy of recruitment maneuvers ( RMs ) in patients with acute lung injury ( ALI ) .
OBJECTIVES To summarize the physiologic effects and adverse events in adult patients with ALI receiving RMs .