Gaetan Beduneau

High-Flow Oxygen through Nasal Cannula in Acute Hypoxemic Respiratory Failure

BACKGROUND Whether noninvasive ventilation should be administered in patients with acute hypoxemic respiratory failure is debated. Therapy with high-flow oxygen through a nasal cannula may offer an alternative in patients with hypoxemia. METHODS We performed a multicenter, open-label trial in which we randomly assigned patients without hypercapnia who had acute hypoxemic respiratory failure and a ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen of 300 mm Hg or less to high-flow oxygen therapy, standard oxygen therapy delivered through a face mask, or noninvasive positive-pressure ventilation. The primary outcome was the proportion of patients intubated at day 28; secondary outcomes included all-cause mortality in the intensive care unit and at 90 days and the number of ventilator-free days at day 28. RESULTS A total of 310 patients were included in the analyses. The intubation rate (primary outcome) was 38% (40 of 106 patients) in the high-flow-oxygen group, 47% (44 of 94) in the standard group, and 50% (55 of 110) in the noninvasive-ventilation group (P=0.18 for all comparisons). The number of ventilator-free days at day 28 was significantly higher in the high-flow-oxygen group (24±8 days, vs. 22±10 in the standard-oxygen group and 19±12 in the noninvasive-ventilation group; P=0.02 for all comparisons). The hazard ratio for death at 90 days was 2.01 (95% confidence interval [CI], 1.01 to 3.99) with standard oxygen versus high-flow oxygen (P=0.046) and 2.50 (95% CI, 1.31 to 4.78) with noninvasive ventilation versus high-flow oxygen (P=0.006). CONCLUSIONS In patients with nonhypercapnic acute hypoxemic respiratory failure, treatment with high-flow oxygen, standard oxygen, or noninvasive ventilation did not result in significantly different intubation rates. There was a significant difference in favor of high-flow oxygen in 90-day mortality. (Funded by the Programme Hospitalier de Recherche Clinique Interrégional 2010 of the French Ministry of Health; FLORALI ClinicalTrials.gov number, NCT01320384.).

Diagnostic bronchoscopy in hematology and oncology patients with acute respiratory failure: prospective multicenter data.

Objective:To describe the diagnostic yields of test strategies with and without fiberoptic bronchoscopy and bronchoalveolar lavage (FO-BAL), as well as outcomes, in cancer patients with acute respiratory failure (ARF). Design:Prospective observational study. Setting:Fifteen intensive care units in France. Patients:In all, 148 cancer patients, including 45 bone marrow transplant recipients (27 allogeneic, 18 autologous) with hypoxemic ARF. Intervention:None. Results:Overall, 146 causes of ARF were identified in 128 patients (97 [66.4%] pulmonary infections). The cause of ARF was identified in 50.5% of the 101 patients who underwent FO-BAL and in 66.7% of the other patients. FO-BAL was the only conclusive test in 34 (33.7%) of the 101 investigated patients. Respiratory status deterioration after FO-BAL occurred in 22 of 45 (48.9%) nonintubated patients, including 16 (35.5%) patients who required ventilatory support. Hospital mortality was 55.4% (82 deaths) overall and was not significantly different in the groups with and without FO-BAL. By multivariate analysis, mortality was affected by characteristics of the malignancy (remission, allogeneic bone marrow transplantation), cause of ARF (ARF during neutropenia recovery, cause not identified), and need for life-sustaining treatments (mechanical ventilation and vasopressors). Conclusion:In critically ill cancer patients with ARF, a diagnostic strategy that does not include FO-BAL may be as effective as FO-BAL without exposing the patients to respiratory status deterioration.

A multicenter, randomized trial of noninvasive ventilation with helium-oxygen mixture in exacerbations of chronic obstructive lung disease.

Objective:To assess the effect of a helium-oxygen mixture on intubation rate and clinical outcomes during noninvasive ventilation in acute exacerbation of chronic obstructive pulmonary disease. Design:Multicenter, prospective, randomized, controlled trial. Setting:Seven intensive care units. Patients:A total of 204 patients with known or suspected chronic obstructive pulmonary disease and acute dyspnea, Paco2> 45 mm Hg and two among the following factors: pH <7.35, Paco2 <50 mm Hg, respiratory rate >25/min. Interventions:Noninvasive ventilation randomly applied with or without helium (inspired oxygen fraction 0.35) via a face mask. Measurements and Main Results:Duration and complications of NIV and mechanical ventilation, endotracheal intubation, discharge from intensive care unit and hospital, mortality at day 28, adverse and serious adverse events were recorded. Follow-up lasted until 28 days since enrollment. Intubation rate did not significantly differ between groups (24.5% vs. 30.4% with or without helium, p = .35). No difference was observed in terms of improvement of arterial blood gases, dyspnea, and respiratory rate between groups. Duration of noninvasive ventilation, length of stay, 28-day mortality, complications and adverse events were similar, although serious adverse events tended to be lower with helium (10.8% vs. 19.6%, p = .08). Conclusions:Despite small trends favoring helium, this study did not show a statistical superiority of using helium during NIV to decrease the intubation rate in acute exacerbation of chronic obstructive pulmonary disease.

Epidemiology of Weaning Outcome according to a New Definition. The WIND Study

Rationale: The weaning process concerns all patients receiving mechanical ventilation. A previous classification into simple, prolonged, and difficult weaning ignored weaning failure and presupposed the use of spontaneous breathing trials. Objectives: To describe the weaning process, defined as starting with any attempt at separation from mechanical ventilation and its prognosis, according to a new operational classification working for all patients under ventilation. Methods: This was a multinational prospective multicenter observational study over 3 months of all patients receiving mechanical ventilation in 36 intensive care units, with daily collection of ventilation and weaning modalities. Pragmatic definitions of separation attempt and weaning success allowed us to allocate patients in four groups. Measurements and Main Results: A total of 2,729 patients were enrolled. Although half of them could not be classified using the previous definition, 99% entered the groups on the basis of our new definition as follows: 24% never started a weaning process, 57% had a weaning process of less than 24 hours (group 1), 10% had a difficult weaning of more than 1 day and less than 1 week (group 2), and 9% had a prolonged weaning duration of 1 week or more (group 3). Duration of ventilation, intensive care unit stay, and mortality (6, 17, and 29% for the three groups, respectively) all significantly increased from one group to the next. The unadjusted risk of dying was 19% after the first separation attempt and increased to 37% after 10 days. Conclusions: A new classification allows us to categorize all weaning situations. Every additional day without a weaning success after the first separation attempt increases the risk of dying.

Ventilator-Associated Pneumonia During Weaning From Mechanical Ventilation: Role of Fluid Management

BACKGROUND Pulmonary edema may alter alveolar bacterial clearance and infectivity. Manipulation of fluid balance aimed at reducing fluid overload may, therefore, influence ventilator-associated pneumonia (VAP) occurrence in intubated patients. The objective of the present study was to assess the impact of a depletive fluid-management strategy on ventilator-associated complication (VAC) and VAP occurrence during weaning from mechanical ventilation. METHODS We used data from the B-type Natriuretic Peptide for the Fluid Management of Weaning (BMW) randomized controlled trial performed in nine ICUs across Europe and America. We compared the cumulative incidence of VAC and VAP between the biomarker-driven, depletive fluid-management group and the usual-care group during the 14 days following randomization, using specific competing-risk methods (the Fine and Gray model). RESULTS Among the 304 patients analyzed, 41 experienced VAP, including 27 (17.8%) in the usual-care group vs 14 (9.2%) in the interventional group (P = .03). From the Fine and Gray model, the probabilities of VAC and VAP occurrence were both significantly reduced with the interventional strategy while adjusting for weaning outcome as a competing event (subhazard ratios [25th-75th percentiles], 0.44 [0.22-0.87], P = .02 and 0.50 [0.25-0.96], P = .03, respectively). CONCLUSIONS Using proper competing risk analyses, we found that a depletive fluid-management strategy, when initiating the weaning process, has the potential for lowering VAP risk in patients who are mechanically ventilated. TRIAL REGISTRY ClinicalTrials.gov; No.: NCT00473148; URL: www.clinicaltrials.gov.

Original ResearchCritical CareVentilator-Associated Pneumonia During Weaning From Mechanical Ventilation: Role of Fluid Management

BACKGROUND Pulmonary edema may alter alveolar bacterial clearance and infectivity. Manipulation of fluid balance aimed at reducing fluid overload may, therefore, influence ventilator-associated pneumonia (VAP) occurrence in intubated patients. The objective of the present study was to assess the impact of a depletive fluid-management strategy on ventilator-associated complication (VAC) and VAP occurrence during weaning from mechanical ventilation. METHODS We used data from the B-type Natriuretic Peptide for the Fluid Management of Weaning (BMW) randomized controlled trial performed in nine ICUs across Europe and America. We compared the cumulative incidence of VAC and VAP between the biomarker-driven, depletive fluid-management group and the usual-care group during the 14 days following randomization, using specific competing-risk methods (the Fine and Gray model). RESULTS Among the 304 patients analyzed, 41 experienced VAP, including 27 (17.8%) in the usual-care group vs 14 (9.2%) in the interventional group (P = .03). From the Fine and Gray model, the probabilities of VAC and VAP occurrence were both significantly reduced with the interventional strategy while adjusting for weaning outcome as a competing event (subhazard ratios [25th-75th percentiles], 0.44 [0.22-0.87], P = .02 and 0.50 [0.25-0.96], P = .03, respectively). CONCLUSIONS Using proper competing risk analyses, we found that a depletive fluid-management strategy, when initiating the weaning process, has the potential for lowering VAP risk in patients who are mechanically ventilated. TRIAL REGISTRY ClinicalTrials.gov; No.: NCT00473148; URL: www.clinicaltrials.gov.

Bedside adjustment of proportional assist ventilation to target a predefined range of respiratory effort.

Objectives:During proportional assist ventilation with load-adjustable gain factors, peak respiratory muscle pressure can be estimated from the peak airway pressure and the percentage of assistance (gain). Adjusting the gain can, therefore, target a given level of respiratory effort. This study assessed the clinical feasibility of titrating proportional assist ventilation with load-adjustable gain factors with the goal of targeting a predefined range of respiratory effort. Design:Prospective, multicenter, clinical observational study. Settings:Intensive care departments at five university hospitals. Patients:Patients were included after meeting simple criteria for assisted mechanical ventilation. Interventions:Patients were ventilated in proportional assist ventilation with load-adjustable gain factors. The peak respiratory muscle pressure, estimated in cm H2O as (peak airway pressure – positive end-expiratory pressure) × [(100 – gain)/gain], was calculated from a grid at the bedside. The gain adjustment algorithm was defined to target a peak respiratory muscle pressure between 5 and 10 cm H2O. Additional recommendations were available in case of hypoventilation or hyperventilation. Results:Fifty-three patients were enrolled. Median time spent under proportional assist ventilation with load-adjustable gain factors was 3 days (interquartile range, 1–5). Gain was adjusted 1.0 (0.7–1.8) times per day, according to the peak respiratory muscle pressure target range in 91% of cases and because of hypoventilation or hyperventilation in 9%. Thirty-four patients were ventilated with proportional assist ventilation with load-adjustable gain factors until extubation, which was successful in 32. Eighteen patients required volume assist-controlled reventilation because of clinical worsening and need for continuous sedation. One patient was intolerant to proportional assist ventilation with load-adjustable gain factors. Conclusions:This first study assessing the clinical feasibility of titrating proportional assist ventilation with load-adjustable gain factors in an attempt to target a predefined range of effort showed that adjusting the level of assistance to maintain a predefined boundary of respiratory muscle pressure is feasible, simple, and often sufficient to ventilate patients until extubation.

Accuracy and precision of end-expiratory lung-volume measurements by automated nitrogen washout/washin technique in patients with acute respiratory distress syndrome

IntroductionEnd-expiratory lung volume (EELV) is decreased in acute respiratory distress syndrome (ARDS), and bedside EELV measurement may help to set positive end-expiratory pressure (PEEP). Nitrogen washout/washin for EELV measurement is available at the bedside, but assessments of accuracy and precision in real-life conditions are scant. Our purpose was to (a) assess EELV measurement precision in ARDS patients at two PEEP levels (three pairs of measurements), and (b) compare the changes (Δ) induced by PEEP for total EELV with the PEEP-induced changes in lung volume above functional residual capacity measured with passive spirometry (ΔPEEP-volume). The minimal predicted increase in lung volume was calculated from compliance at low PEEP and ΔPEEP to ensure the validity of lung-volume changes.MethodsThirty-four patients with ARDS were prospectively included in five university-hospital intensive care units. ΔEELV and ΔPEEP volumes were compared between 6 and 15 cm H2O of PEEP.ResultsAfter exclusion of three patients, variability of the nitrogen technique was less than 4%, and the largest difference between measurements was 81 ± 64 ml. ΔEELV and ΔPEEP-volume were only weakly correlated (r2 = 0.47); 95% confidence interval limits, -414 to 608 ml). In four patients with the highest PEEP (≥ 16 cm H2O), ΔEELV was lower than the minimal predicted increase in lung volume, suggesting flawed measurements, possibly due to leaks. Excluding those from the analysis markedly strengthened the correlation between ΔEELV and ΔPEEP volume (r2 = 0.80).ConclusionsIn most patients, the EELV technique has good reproducibility and accuracy, even at high PEEP. At high pressures, its accuracy may be limited in case of leaks. The minimal predicted increase in lung volume may help to check for accuracy.

Interest of a simple on-line screening registry for measuring ICU burden related to an influenza pandemic

IntroductionThe specific burden imposed on Intensive Care Units (ICUs) during the A/H1N1 influenza 2009 pandemic has been poorly explored. An on-line screening registry allowed a daily report of ICU beds occupancy rate by flu infected patients (Flu-OR) admitted in French ICUs.MethodsWe conducted a prospective inception cohort study with results of an on-line screening registry designed for daily assessment of ICU burden.ResultsAmong the 108 centers participating to the French H1N1 research network on mechanical ventilation (REVA) - French Society of Intensive Care (SRLF) registry, 69 ICUs belonging to seven large geographical areas voluntarily participated in a website screening-registry. The aim was to daily assess the ICU beds occupancy rate by influenza-infected and non-infected patients for at least three weeks. Three hundred ninety-one critically ill infected patients were enrolled in the cohort, representing a subset of 35% of the whole French 2009 pandemic cohort; 73% were mechanically ventilated, 13% required extra corporal membrane oxygenation (ECMO) and 22% died. The global Flu-OR in these ICUs was only 7.6%, but it exceeded a predefined 15% critical threshold in 32 ICUs for a total of 103 weeks. Flu-ORs were significantly higher in University than in non-University hospitals. The peak ICU burden was poorly predicted by observations obtained at the level of large geographical areas.ConclusionsThe peak Flu-OR during the pandemic significantly exceeded a 15% critical threshold in almost half of the ICUs, with an uneven distribution with time, geographical areas and between University and non-University hospitals. An on-line assessment of Flu-OR via a simple dedicated registry may contribute to better match resources and needs.

The Use of Ferritin to Identify Critically Ill Patients With Secondary Hemophagocytic Lymphohistiocytosis.

Objectives:Thrombocytopenia is a common, multifactorial, finding in ICU. Hemophagocytosis is one of the main explanatory mechanisms, possibly integrated into hemophagocytic lymphohistiocytosis syndrome, of infectious origin in the majority of cases in ICU. The hemophagocytic lymphohistiocytosis is probably underdiagnosed in the ICU, although it is associated with dramatic outcomes. The main objectives of this work were to identify the frequency of secondary hemophagocytic lymphohistiocytosis, and the main prognostic factors for mortality. Design/Setting:We conducted a retrospective observational study in all adult patients admitted with suspected or diagnosed hemophagocytic lymphohistiocytosis, between January 1, 2000, and August 22, 2012. Patients:A total of 106 patients (42%) had significant hemophagocytosis on bone marrow examination, performed for exploration of thrombocytopenia, bicytopenia, or pancytopenia. Measurements and Main Results:The median age was 56 (45–68) and the median Simplified Acute Physiology Score 2 was 55 (38–68). The main reason for ICU admission was hemodynamic instability (58%), predominantly related to sepsis (45% cases). The main precipitating factor found was a bacterial infection in 81 of 106 patients (76%), including 32 (30%) with Escherichia coli infection. Forty six of 106 patients (43%) died in the ICU. They were significantly older, had higher Simplified Acute Physiology Score 2, plasma lactate deshydrogenase bilirubin, and serum ferritin. The fibrinogen and the percentage of megakaryocytes were significantly lower in nonsurvivors when compared with survivors. In multivariate analysis, only serum ferritin significantly predicted death related to hemophagocytosis. A serum ferritin greater than 2,000 &mgr;g/L predicted death with a sensitivity of 71% and a specificity of 76%. A decreased percentage of megakaryocytes also predicted patient death in the ICU. Conclusions:Hemophagocytosis is common in thrombocytopenic patients with sepsis, frequently included in a postinfectious hemophagocytic lymphohistiocytosis setting. Our study reveals that ferritin could be a reliable prognostic marker in these patients, and hold particular interest in discussing a specific treatment for hemophagocytic lymphohistiocytosis.