Early infectious acute respiratory distress syndrome is characterized by activation and proliferation of alveolar T-cells.

Acute respiratory distress syndrome (ARDS) in humans is characterized by the infiltration of polymorphonuclears in the alveolar spaces. However, the role of T-cells in ARDS is unknown. Our aim was to characterize the T-cell phenotype in bronchoalveolar lavage (BAL) during the early phase of acute lung infection(ALI)/ARDS-infected patients in comparison to a control group (CG). BAL lymphocyte phenotypes of two ALI, 16 ARDS, and eight CG were examined by flow cytometry. ALI/ARDS showed a significant increase in CD4 and CD8 T-cell activation as compared to CG. Moreover, a significant level of proliferation was observed using the Ki67 marker in ARDS patients as compared to controls (median): 37 versus 6 % for CD4 T-cells (p = 0.022) and 34 versus 2 % for CD8 T-cells (p = 0.009). In contrast, the percentage of T-regulatory cells and apoptotic T-cells were similar in both groups. Among costimulatory molecules, we observed an overexpression of CTLA-4/CD152 on CD4 T-cells in ALI/ARDS as compared to CG: 30 versus 7 %, respectively (p = 0.063). In further characterizing T-cell subsets expressing high levels of CD152, we found the presence of IL-17 secreting CD4 T-cells in ALI/ARDS. In humans, ALI/ARDS due to infection is associated with a high level of T-cell activation and proliferation, along with the presence of Th17 cells, which are known to attract polymorphonuclears.

Enhanced T-cell apoptosis in human septic shock is associated with alteration of the costimulatory pathway.

T-cell apoptosis during septic shock (SS) has been associated with deleterious outcome, but the mechanisms of apoptosis are not well understood. As T-cells are not infected in bacterial infection, our hypothesis was that deleterious interactions between lymphocytes and monocytes could be involved. This is a cross-sectional study of 27 patients presenting with community-acquired SS, 23 infected patients without SS and 18 controls. Cytofluorometric techniques were used to study apoptosis, the costimulatory pathway and cytokine synthesis. Apoptosis was increased in SS compared to infected patients without SS and controls: the median values were 18, 2 and 3%, respectively, for CD4(+) T-cells (P < 0.001), and 12, 5 and 2%, respectively, for CD8(+) T-cells (P < 0.001). Patients with SS exhibited significant CD152 over-expression on T-cells, while CD86 expression was decreased on monocytes (P = 0.004). The synthesis of interleukin-2 was decreased in patients with SS compared to the other groups, while secretions of interferon-gamma and TNF-alpha were not altered. Ten surviving patients with SS showed a trend towards the normalisation of these parameters on day 7. In SS, T-cell apoptosis is related, at least in part, to the alteration of the costimulatory pathway, which, in turn, leads to significant modification of the cytokine network.

[Acute airway obstruction during chemotherapy-induced agranulocytosis with fever]. / Moules bronchiques au cours d'une agranulocytose fébrile post-chimiothérapie.

Acute airway obstruction caused by mucoid impaction can cause sometimes life-threatening respiratory distress. Bronchial plugging is usually observed in subjects with chronic diseases such as asthma, allergic bronchopulmonary aspergillosis, or cystic fibrosis. In children, it can be related to heart failure. Acute airway obstruction in a patient without a chronic respiratory disease is exceptional. We report the case of a patient who developed bronchial plugs obstructing the bronchi during a period of agranulocytosis induced by chemotherapy. The patient experienced acute respiratory distress with asphyxia. The plugs were composed of fibrin and required several fibroscopic procedures for clearance. To our knowledge, this is the first case report of acute airway obstruction by plugging during a period of agranulocytosis.

Blood pressure and arterial lactate level are early indicators of short-term survival in human septic shock.

OBJECTIVE: To identify early prognostic markers of septic shock among catheterization-derived hemodynamic and metabolic data. DESIGN: Prospective cohort study. SETTING: A medical intensive care unit in a university hospital. PATIENTS: Thirty-two consecutive patients with septic shock, separated into two groups according to short-term (10-day) evolution: 18 acute survivors and 14 fatalities. MEASUREMENTS: Usual hemodynamic and metabolic variables were measured at the onset of shock, i.e., when the catheter was inserted (T0), and 24 h later (T24). The values collected for each group at T0 and T24 and their 24-h changes were compared. RESULTS: On admission, no difference was found between acute survivors and eventual fatalities. After 24 h, fatalities presented with significantly lower mean arterial pressure (p <0.01), left ventricular stroke work index (p <0.05) and higher lactate levels (p <0.01) than acute survivors. Moreover, the 24-h changes of lactate and blood pressure were also of prognostic value (p <0.05). Oxygen delivery and oxygen consumption did not differ statistically between the two groups. At T24, a mean arterial pressure of less than 85 mmHg and a lactate level equal to or greater than 3.5 mmol/l were independently associated with poor survival (37.5% and 30.7%, respectively). Day 10 survival was only 12.5% when both criteria were present at T24. CONCLUSIONS: Changes in mean arterial pressure and arterial blood lactate within the first 24 h of treatment are strong prognostic indicators of short-term survival in patients with septic shock. After 24 h of treatment, maintenance of a mean blood pressure equal to or greater than 85 mmHg correlates with survival at day 10. Data suggest that early reductions in both cardiac function and vascular tone play a determining role in the hypotension observed in fatalities. Persistence of hyperlactatemia in hypotensive patients bodes particularly ill. Blood pressure and lactate level are simple bedside parameters that can enable the clinician to identify patients with a high risk of mortality.

Influence of alveolar ventilation changes on calculated gastric intramucosal pH and gastric-arterial PCO2 difference.

OBJECTIVE: To evaluate the influence of changes in alveolar ventilation on the following tonometry-derived variables: gastric intramucosal CO2 tension (PtCO2), gastric arterial CO2 tension difference (PgapCO2), gastric intramucosal pH (pHi) and arterial pH-pHi difference (pHgap). DESIGN: Clinical prospective study. SETTING: A medical intensive care unit in a university hospital. PATIENTS: Ten critically ill, mechanically ventilated patients requiring hemodynamic monitoring with pulmonary artery catheter. INTERVENTIONS: Gastric tonometer placement. A progressive increase in tidal volume (V(T)) from 7 to 10 ml/ kg followed by an abrupt return to baseline V(T) level. MEASUREMENTS AND MAIN RESULTS: Tonometer saline PtCO2 and hemodynamic data were collected hourly at various V(T) levels: H0 and H0' (baseline V(T) = 7 ml/kg), H1 (V(T) = 8 ml/kg), H2 (V(T) = 9 ml/kg), H3 (V(T) = 10 ml/kg), H4 (baseline V(T)). During the "hyperventilation phase" (H0-H3), pHi (p<0.01) and pHgap (p<0.05) increased but PgapCO2 remained unchanged. Cardiac output (CO) was not affected by ventilatory change. During the "hypoventilation phase" (H3-H4), pHi fell from 7.27+/-0.11 to 7.23+/-0.09 (p<0.01) and PgapCO2 decreased from 16+/-5 mm Hg to 13+/-4 mm Hg (p<0.05). V(T) reduction was associated with a significant cardiac output elevation (p<0.05). CONCLUSIONS: PaCO2 and PtCO2 are similarly influenced by the changes in alveolar ventilation. Unlike pHi, the PgapCO2 is not affected by ventilation variations unless CO changes are associated.

Beta-adrenergic receptor-dependent and -independent stimulation of adenylate cyclase is impaired during severe sepsis in humans.

OBJECTIVES: a) To investigate the functional consequences of sepsis on the beta-adrenergic signal transduction in human circulating lymphocytes; b) to appreciate sepsis-associated catecholamine and cytokine release. DESIGN: Experimental, comparative study. SETTING: Research laboratory in a university hospital. SUBJECTS: Healthy controls (n = 10); critically ill patients who were not septic (n = 7); septic patients with severe sepsis or septic shock (n = 11). MEASUREMENTS AND MAIN RESULTS: Experiments were carried out using freshly isolated peripheral blood mononuclear cells (PBMC). We measured beta-adrenergic receptor (betaAR) number and affinity, and intracellular cAMP content at baseline and after the pharmacological stimulation of each component of the beta-adrenergic complex: betaAR with isoproterenol, Gs-protein with sodium fluoride (NaF), adenylate cyclase with forskolin. Catecholamine (adrenaline, noradrenaline) and cytokine (TNFalpha, IL-1alpha, IL-1beta, IL-6) serum levels were measured. In both septic and non-septic patients we observed a similar 40 % down-regulation of betaARs compared to controls, and a reduced basal and isoproterenol-stimulated cAMP accumulation (p < 0.05). The cAMP production elicited by NaF or forskolin was lower in septic patients than in the controls (p < 0.01). Forskolin-stimulated cAMP accumulation was significantly lower in septic patients than it was in non-septic ones (p < 0.001). Catecholamine serum concentrations were increased in the two patient groups without any significant difference. Elevated cytokine serum levels were detected in 45% of the septic patients (versus 14% of non-septic patients p < 0.05). CONCLUSIONS: Patients presenting with severe sepsis or septic shock have extended postreceptor defects of the beta-adrenergic signal transduction. This finding suggests a heterologous desensitization of adenylate cyclase stimulation.

Swan-Ganz catheter-related pulmonary valve infective endocarditis: a case report.

We report the case of a 29-year-old man with decompensated alcoholic cardiomyopathy who developed a Staphylococcal pulmonic valve infective endocarditis during hemodynamic monitoring, as a consequence of catheter-related bacteremia. As experimentally demonstrated, the damaging role of the pulmonary artery catheter on the endocardial surface plays a major role in the pathogenesis of related right-sided infective endocarditis. Occurrence of bacteremia in a catheterized patient should be considered as a high risk situation, and righ-heart infective endocarditis must be suspected whenever patient presents fever or bacteremia without obvious site of infection. Doppler echocardiography is the reference diagnosis procedure.

Consensual treatment of plasmodium falciparum malaria does not lead to adequate quinine blood concentrations.

Since 1996, we have a common protocol in the Infectious Diseases Department and the Intensive Care Unit for the administration of quinine in case of Plasmodium falciparum malaria. Patients were classified as uncomplicated form of malaria (UFM) or severe form of malaria (SFM) according to WHO criteria, adding parasitemia >5% as a criteria of SFM. Treatment of SFM should consist of a 4 h infusion of 16 mg/kg quinine-base loading dose, followed by 8 mg/kg every 8 h. Patients with UFM receive quinine-base, 8 mg/kg every 8 h. A therapeutic index of 10-15 mg/l was considered adequate. Hypoglycemia and cardiotoxicity were the two main adverse effects of quinine to be investigated. In order to verify that these modalities for quinine administration are associated with adequate quinine blood concentrations, we have reviewed the pharmacological data and the occurrence of adverse effects. Between April 1996 and December 2000, 95 patients were hospitalised: 25 with SFM and 70 with UFM: 78/95 patients (82%) received adequate treatment and 26/95 (28%) of the patients presented an overdosage of quinine. Six severe adverse effects were observed, even in case of adequate quinine administration. Consensual treatment of malaria does not confer adequate quinine blood concentrations, and toxic effects are still common.

Continuous noninvasive measurement of aortic blood flow in critically ill patients with a new esophageal echo-Doppler system.

PURPOSE: Determination of aortic blood flow (ABF) using esophageal Doppler has been proposed as a low invasive hemodynamic monitoring method. The esophageal echo-Doppler Dynemo 3000 (Sometec Inc., Paris, France) system, recently available on the market, is an original device measuring simultaneously, and at the same anatomic level, aortic diameter, and blood flow velocity. Until now, this material has been used exclusively for peroperative monitoring. The objectives of the study were to assess the feasibility and reliability of use for continuous measurements of ABF in hemodynamically compromised intensive care unit patients; and to compare ABF values and its change induced by preload manipulation with the cardiac output (CO) values measured simultaneously by the standard thermodilution method. MATERIALS AND METHODS: Sixty simultaneous measurements of ABF and CO were performed in 22 intensive care unit patients. In 16 hypovolemic patients, Doppler and thermodilution measurements were repeated after fluid replacement. RESULTS: Applicability of the method was 84.6% (failure of the echo-Doppler method in 4 of 26 eligible patients). Coefficient of variation of echo-Doppler-derived ABF was 3.25 +/- 2.26%. Interobserver variability was 3.3 +/- 1.6%. Close linear relationship was found between ABF and CO (r = 0.92). Average ABF/CO ratio was 73 +/- 10%, but significant variation was observed after fluid replacement. CONCLUSIONS: The echo-Doppler Dynemo 3000 system allows reliable continuous measurements of ABF in intensive care unit patients, both easily and safely.

[Central apnea with consciousness impairment due to Listeria rhombencephalitis sequelae]. / Apnées centrales avec troubles de la vigilance, séquelle de rhombencéphalite listérienne.

Listeria neuromeningitis presents as febrile rhombencephalitis in half the patients, often with persistent sequelae such as cranial nerve palsy. We report the case of a man who developed central apnea with simultaneous consciousness impairment subsequent to an infectious disease. Magnetic resonance imaging showed low signal intensities in T1 and T2, particularly in the medulla. Neither acidosis, hypoxia nor hypercapnea stimulated the respiratory centers during episodes of apnea; ventilation started again only with strong voluntary stimulation. Pons and medulla lesions of the reticular formation were probable as well as lesions of the automatic respiratory system and could explain the central origin of the apnea in this patient.

[Two-dimensional echocardiography during the acute phase of myocardial infarction. Diagnostic and prognostic value]. / Echocardiographie bidimensionnelle à la phase aiguë de l'infarctus du myocarde. Valeur diagnostique et pronostique.

A bidimensional cardiac sonogram was performed in 152 consecutive patients with in 24 hours after hospitalization in the intensive care unit for acute myocardial infarction, in order to evaluate the contribution of this technique to the diagnosis, determination of early complication and the prognosis. For this study, the left ventricle was divided in 10.segments. For each segment, systolic mobility as well as thickness were evaluated. It was possible to obtain a proper recording in 134 patients. Abnormal left ventricular kinetics (at least 1 segment) is present in all anterior transmural infarctions with, in 90 p. cent of the cases, a concordance between electrical and sonographic localization and in 89 p. cent of inferior between electrical and sonographic localization and in 89 p. cent of inferior only present in 65 p. cent. Abnormal kinetics is only present in 65 p. cent of non transmural infarctions. In 15 patients with clinical infarction without any electrical sign, the cardiac sonogram permitted to make the diagnosis and establish the localization of the infarction. In 46 p. cent of the cases, a left ventricular asynergy was observed at a distance of the necrosed area. In these patients, the mortality and cardiogenic shock rates during hospitalization were higher than for patients who did not present these abnormal findings (p less than 0.01). In conclusion, bidimensional cardiac sonography is a very specific diagnostic tool, permitting an early prognosis and able to detect early complication, especially of pericardial and mechanical nature.

[Bacterial meningitis in adults in the intensive care unit. Clinical analysis and study of prognostic factors]. / Méningites bactériennes de l'adulte en réanimation médicale. Analyse clinique et étude des facteurs pronostiques.

OBJECTIVES: Bacterial meningitis frequently leads to hospitalization in the intensive care unit. Despite progress in antibiotics, prognosis remains poor. METHODS: We analyzed the clinical manifestations and complications which occurred in 41 patients admitted to the intensive care unit for bacterial meningitis. A case-control survey was used to determine prognosis factors. RESULTS: All patients required ventilatory assistance and 83% were in a state of coma at admission. Causal germs isolated were: Pneumococci 34%, Listeria 22%, Staphylococcus aureus 17%, and Gram-positive bacilli 12%. Overall mortality was 56%. The main prognosis factors after univariate analysis were age, delay to treatment, presence of septic shock, bacteriemia at admission, low cell count in first lumbar tap, high urea level and low protein level. After multivariate analysis, the following risk factors were retained: low number of leukocytes at first lumbar tap and high urea level. CONCLUSION: The gravity of bacterial meningitis in the intensive care unit appears to be related to the patient's overwhelmed defense system and especially to hemodynamic disorders with acute renal failure and capillary hyperpermeability leading to insufficient cerebral perfusion.

[Prognosis of acute tuberculous respiratory distress syndrome. 4 cases]. / Pronostic du syndrome de détresse respiratoire aiguë tuberculeux. 4 observations.

OBJECTIVES: We examined the characteristics of 4 cases of adult respiratory distress syndrome in patients with tuberculosis in an attempt to improve prognosis. METHODS: Four new cases of adult respiratory distress syndrome were described together with a review of the cases reported in the literature. Inclusion criteria were the presence of the syndrome as defined according to the American-European consensus conference and the criteria described by Murray et al. and identification of the mycobacteria causing tuberculosis. RESULTS: A total of 52 cases were included in the study. The sex ratio was 0.71 and mean age 46 +/- 15 years. Eight patients had a past history of pulmonary tuberculosis. Alcoholism was the primary immunodepression factor observed (35%) followed by human immunodeficiency virus infection (13%). For 74% of the patients, the disease course lasted 7 days. The initial chest X-ray was suggestive of tuberculosis in 11. Intradermoreaction to tuberculin was positive in 2 out of 17 patients. Direct examination of non-invasive respiratory samples was positive in 44% for mycobacteria. Disseminated tuberculosis was seen in 64%. Anti-tuberculosis antibiotherapy was started on the first day of intensive care in 68% of the patients; rapid treatment was associated with better prognosis: 1.5 +/- 1.2 days versus 3 +/- 2.7 in fatal cases (p = 0.02). Adjuvant corticosteroid therapy was used in 46% of the cases and was apparently associated with unfavourable outcome: 74% mortality versus 58% without corticosteroids. Ventilatory assistance was required in 88% and associated with poor prognosis (13% survival versus 100% without assistance) (p < 10(-3)). Outcome was fatal in 36 cases (70%) with a mean delay of 9.7 +/- 10.8 days. CONCLUSION: The conditions required for improving the prognosis of adult respiratory distress syndrome in tuberculosis patients included suspecting tuberculosis in all cases of acute respiratory failure of unknown origin, particularly in the immunodepressed patient, and to avoid missing this diagnosis in case of a non-suggestive chest X-ray and a negative though exhaustive microbiology search. Adjuvant corticotherapy is uneffective and may be dangerous.

[Systematic infection consultation in the intensive care unit. Impact of short-term antibiotic use]. / Consultation systématique d'infectiologie en réanimation médicale. Impact à court terme sur la consommation antibiotique.

OBJECTIVES: Multiresistant bacteria are regularly isolated in nosocomial infections occurring in intensive care units due to wide use of antibiotics. We evaluated the impact of systematic infectiology consultations on the quality of antibiotic prescriptions in an intensive care unit. PATIENTS AND METHODS: Infectiology consultations (3 per week) were initiated mid February 1999. The infectiologist gave oral advice to be implemented (or not) by the intensive care unit according to ongoing therapeutic options. The hospital pharmacy recorded antibiotic use for March and April 1999 for comparison with use recorded in 1998 for a similar period. We retrospectively reviewed the files of patients hospitalized during these periods and who had received antibiotics to determine the modalities of antibiotic use. The 4 antibiotics used for the longest period for each patient were recorded. RESULTS: Thirty-one patients in 1999 and 30 in 1998 were given antibiotics. The SAPS score was similar for the two groups. Mean duration of antibiotic treatment was lower during the March-April 1999 period than during the corresponding period in 1998: 13 +/- 9 days/patient versus 23 +/- 21 days/patient respectively, p = 0.037. In 1998, there were 596 antibiotic-days and in 1999 there were 455 (-24%). The cost of antibiotic therapy in 1998 was 70,342 FrF compared with 56,804 FrF in 1999 (-19%). CONCLUSION: Infectiology consultation, in association with the opinion of the intensive care physician, is a simple way to limit antibiotic use.

Effect of different seated positions on lung volume and oxygenation in acute respiratory distress syndrome.

RATIONALE: Lung volume available for ventilation is markedly decreased during acute respiratory distress syndrome. Body positioning may contribute to increase lung volume and partial verticalization is simple to perform. This study evaluated whether verticalization had parallel effects on oxygenation and end expiratory lung volume (EELV). METHODS: Prospective multicenter study in 40 mechanically ventilated patients with ALI/ARDS in five university hospital MICUs. We evaluated four 45-min successive trunk position epochs (supine slightly elevated at 15°; semi recumbent with trunk elevated at 45°; seated with trunk elevated at 60° and legs down at 45°; back to supine). Arterial blood gases, EELV measured using the nitrogen washin/washout, and static compliance were measured. Responders were defined by a PaO2/FiO2 increase >20 % between supine and seated position. Results are median [25th-75th percentiles]. RESULTS: With median PEEP = 10 cmH2O, verticalization increased lung volume but only responders (13 patients, 32 %) had a significant increase in EELV/PBW (predicted body weight) compared to baseline. This increase persisted at least partially when patients were positioned back to supine. Responders had a lower EELV/PBW supine [14 mL/kg (13-15) vs. 18 mL/kg (15-27) (p = 0.005)] and a lower compliance [30 mL/cmH2O (22-38) vs. 42 (30-46) (p = 0.01)] than non-responders. Strain decreased with verticalization for responders. EELV/PBW increase and PaO2/FiO2 increase were not correlated. DISCUSSION: Verticalization is easily achieved and improves oxygenation in approximately 32 % of the patients together with an increase in EELV. Nonetheless, effect of verticalization on EELV/PBW is not predictable by PaO2/FiO2 increase, its monitoring may be helpful for strain optimization.

Impact of an intervention designed to improve the documentation of the reassessment of antibiotic therapies in an intensive care unit.

OBJECTIVES: The study objectives were: (i) to design an intervention to improve the written documentation of empiric antibiotic prescriptions' reassessment; (ii) and to assess the impact of this intervention on the quality of prescriptions. PATIENTS AND METHODS: A prospective before and after 7-month intervention study in a medical ICU in a French teaching hospital, using interrupted time-series analysis. The intervention was made to improve the documentation of four process measures in medical records: antibiotic plan, reviewing the diagnosis, adapting to positive microbiological results, and IV-per os switch. RESULTS: One hundred and fourteen antibiotic prescriptions were assessed, 62 before and 52 after the intervention. The reassessment of antibiotic prescriptions was more often documented in the ICU after the intervention (P=0.03 for sudden change). The prevalence of appropriate antibiotic prescriptions was not statistically different before and after the intervention, either for sudden change and/or linear trend. CONCLUSION: A better documentation of antibiotic prescriptions' reassessment was achieved in this ICU, but it did not improve the quality of antibiotic prescriptions.

Impact of an assisted reassessment of antibiotic therapies on the quality of prescriptions in an intensive care unit.

OBJECTIVES: The study's objective was to assess the impact of a professional multifaceted intervention designed to improve the quality of inpatient empirical therapeutic antibiotic courses at the time of their reassessment, i.e. 24 to 96 hours after treatment initiation. DESIGN: We conducted a 5-month prospective pre- and post-intervention study in a medical Intensive Care Unit (ICU) in a teaching hospital, using time-series analysis. The intervention was a multifaceted professional intervention combining systematic 3-weekly visits of an infectious diseases specialist to discuss all antibiotic therapies, interactive teaching courses, and daily contact with a microbiologist. RESULTS: Eighty-one antibiotic prescriptions were assessed, 37 before and 44 after the intervention. The prevalence of adequate antibiotic prescriptions was high and not statistically different before and after the intervention (73% vs. 80%, P=0.31), both for sudden change (P=0.67) and linear trend (P=0.055), using interrupted time-series analysis. The intervention triggered a more frequent reassessment of the diagnosis between day 2 and day 4 (11% vs. 32%, P=0.02) and slightly improved the adaptation of antibiotic therapies to positive microbiology (25% before vs. 50% after, P=0.18). CONCLUSIONS: Our multifaceted intervention may have improved the quality of antibiotic therapies around day 3 of prescription, but the difference did not reach statistical significance, possibly because of a ceiling effect.

PEEP-induced changes in lung volume in acute respiratory distress syndrome. Two methods to estimate alveolar recruitment.

PURPOSE: Lung volumes, especially functional residual capacity (FRC), are decreased in acute respiratory distress syndrome (ARDS). Positive end-expiratory pressure (PEEP) contributes to increased end-expiratory lung volume (EELV) and to improved oxygenation, but differentiating recruitment of previously nonaerated lung units from distension of previously open lung units remains difficult. This study evaluated simple methods derived from bedside EELV measurements to assess PEEP-induced lung recruitment while monitoring strain. METHODS: Prospective multicenter study in 30 mechanically ventilated patients with ARDS in five university hospital ICUs. Two PEEP levels were studied, each for 45 min, and EELV (nitrogen washout/washin technique) was measured at both levels, with the difference (Δ) reflecting PEEP-induced lung volume changes. Alveolar recruitment was measured using pressure-volume (PV) curves. High and low recruiters were separated based on median recruitment at high PEEP. Minimum predicted increase in lung volume computed as the product of ΔPEEP by static compliance was subtracted from ΔEELV as an independent estimate of recruitment. Estimated and measured recruitments were compared. Strain induced by PEEP was also calculated from the same measurements. RESULTS: FRC was 31 ± 11% of predicted. Median [25th-75th percentiles] PEEP-induced recruitment was 272 [187-355] mL. Estimated recruitment correlated with recruited volume measured on PV curves (ρ = 0.68), with a slope close to identity. The ΔEELV/FRC ratio differentiated high from low recruiters (110 [76-135] vs. 55 [23-70]%, p = 0.001). Strain increase due to PEEP was larger in high recruiters (p = 0.002). CONCLUSION: PEEP-induced recruitment and strain can be assessed at the bedside using EELV measurement. We describe two bedside methods for predicting low or high alveolar recruitment during ARDS.