Jean-Luc Diehl

Positive End-Expiratory Pressure Setting in Adults With Acute Lung Injury and Acute Respiratory Distress Syndrome: A Randomized Controlled Trial

CONTEXT The need for lung protection is universally accepted, but the optimal level of positive end-expiratory pressure (PEEP) in patients with acute lung injury (ALI) or acute respiratory distress syndrome remains debated. OBJECTIVE To compare the effect on outcome of a strategy for setting PEEP aimed at increasing alveolar recruitment while limiting hyperinflation to one aimed at minimizing alveolar distension in patients with ALI. DESIGN, SETTING, AND PATIENTS A multicenter randomized controlled trial of 767 adults (mean [SD] age, 59.9 [15.4] years) with ALI conducted in 37 intensive care units in France from September 2002 to December 2005. INTERVENTION Tidal volume was set at 6 mL/kg of predicted body weight in both strategies. Patients were randomly assigned to a moderate PEEP strategy (5-9 cm H(2)O) (minimal distension strategy; n = 382) or to a level of PEEP set to reach a plateau pressure of 28 to 30 cm H(2)O (increased recruitment strategy; n = 385). MAIN OUTCOME MEASURES The primary end point was mortality at 28 days. Secondary end points were hospital mortality at 60 days, ventilator-free days, and organ failure-free days at 28 days. RESULTS The 28-day mortality rate in the minimal distension group was 31.2% (n = 119) vs 27.8% (n = 107) in the increased recruitment group (relative risk, 1.12 [95% confidence interval, 0.90-1.40]; P = .31). The hospital mortality rate in the minimal distension group was 39.0% (n = 149) vs 35.4% (n = 136) in the increased recruitment group (relative risk, 1.10 [95% confidence interval, 0.92-1.32]; P = .30). The increased recruitment group compared with the minimal distension group had a higher median number of ventilator-free days (7 [interquartile range {IQR}, 0-19] vs 3 [IQR, 0-17]; P = .04) and organ failure-free days (6 [IQR, 0-18] vs 2 [IQR, 0-16]; P = .04). This strategy also was associated with higher compliance values, better oxygenation, less use of adjunctive therapies, and larger fluid requirements. CONCLUSIONS A strategy for setting PEEP aimed at increasing alveolar recruitment while limiting hyperinflation did not significantly reduce mortality. However, it did improve lung function and reduced the duration of mechanical ventilation and the duration of organ failure. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00188058.

Invasive and Noninvasive Strategies for Management of Suspected Ventilator-Associated Pneumonia: A Randomized Trial

The diagnosis and treatment of ventilator-associated pneumonia, a nosocomial infection that develops in mechanically ventilated patients and causes considerable morbidity and mortality, remain a challenge (1-3). A presumptive clinical diagnosis of pneumonia is often made when a patient develops a new radiographic infiltrate associated with fever, leukocytosis, and purulent tracheal secretions and when microorganisms are isolated by nonquantitative analysis of endotracheal aspirates (4). This clinical approach leads to overestimation of the incidence of ventilator-associated pneumonia because cases of tracheobronchial colonization and noninfectious processes mimicking it are included (5-7). The nonspecificity of a strategy based on clinical evaluation has potentially deleterious consequences: Many patients may receive unneeded antibiotics; this exposes them to unnecessary toxicity, increases hospital costs, and favors the emergence of resistant microorganisms. In addition, antibiotic overuse in such patients delays diagnosis of the true cause of fever and pulmonary infiltrate. Concern about the inaccuracy of clinical approaches to diagnosis of ventilator-associated pneumonia led numerous investigators to postulate that invasive diagnostic methods, including quantitative cultures of specimens obtained by using bronchoscopic bronchoalveolar lavage or protected specimen brush, could improve identification of patients with true ventilator-associated pneumonia and selection of appropriate antibiotics (8-10). However, these procedures require rigorous adherence to bronchoscopic and microbiological techniques and are not universally available; moreover, in the absence of a definite gold standard for the diagnosis of ventilator-associated pneumonia, the value of such tests is uncertain, and their use in everyday practice remains controversial (4, 11, 12). To test the hypothesis that an invasive management strategy is superior to a clinical, noninvasive one in terms of improving clinical outcomes and minimizing antibiotic use, we initiated a multicenter, randomized, uncontrolled trial to compare these strategies in patients suspected of having ventilator-associated pneumonia. The primary end points were death from any cause, antibiotic use for any reason, and quantification of organ failure during the first 14 days of follow-up. Methods Patient Selection and Study Design After obtaining approval of the institutional review boards at each participating institution and informed consent from patients or their proxies, we enrolled patients at 31 intensive care units. Inclusion criteria were age older than 18 years; at least 48 hours of mechanical ventilation; and clinical suspicion of ventilator-associated pneumonia, defined by new and persistent infiltrate on chest radiography associated with at least one of the following: purulent tracheal secretions, body temperature of at least 38.3 C, and leukocytosis. Exclusion criteria were pregnancy; enrollment in another interventional study; little chance of survival, defined by a Simplified Acute Physiologic Score II (SAPS II) of more than 65 points (corresponding to a probability of death exceeding 77%) (13); and introduction or modification of antibiotic therapy, instigated by new clinical symptoms, during the 3 days before collection of respiratory samples. For patients in the clinical management group, the decision on whether to treat was based on clinical evaluation and results of immediate microscopic examination of Gram-stained endotracheal aspirates. The results of the Gram stain and recommendations of the American Thoracic Society on hospital-acquired pneumonia were used to guide the initial choice of antibiotics (3). Results of qualitative aspirate cultures were used to adjust the initial antibiotic regimen; when cultures were negative, no treatment was given (Figure 1 A). Figure 1. Diagnostic and therapeutic strategy applied to patients managed with the clinical strategy (A) or invasive strategy (B). The invasive strategy used fiberoptic bronchoscopy to obtain protected specimen brush samples or bronchoalveolar lavage samples for direct microscopic examination. Results of these examinations were used to diagnose ventilator-associated pneumonia, to decide to treat, and to guide the initial choice of antibiotics when specimens were positive. Results of quantitative cultures were used to adjust therapy; treatment was discontinued when results were negative, and use of antibiotics with narrower spectra of activity was based on identification of and susceptibility-test results for pathogens cultured at significant concentrations (protected specimen brush sample that yielded 103 colony-forming units [CFU]/mL or bronchoalveolar lavage fluid sample that yielded 104 CFU/mL [4, 8-10]) (Figure 1 B). For both groups, the recommended duration of therapy for ventilator-associated pneumonia was 14 days. Randomization and Data Collection Patients were randomly assigned to receive the clinical or the invasive management strategy. Computer-generated random-number tables were used to assign patients in blocks of 8, with stratification according to treatment center. At admission to the intensive care unit, we recorded each patients age; sex; severity of underlying medical condition, stratified as rapidly fatal, ultimately fatal, or not fatal according to the criteria of McCabe and Jackson (14); SAPS II score (range, 0 to 174; higher scores indicate more severe illness) (13); Sepsis-related Organ Failure Assessment (SOFA) score (range, 0 to 24, with scores for each organ system [respiration, coagulation, liver, cardiovascular, central nervous system, and kidney] ranging from 0 [normal] to 4 [most abnormal]) (15); the Organ Dysfunction and Infection (ODIN) score (range, 0 to 7, according to the presence or absence of cardiovascular, respiratory, renal, hepatic, hematologic, and neurologic dysfunctions or infection) (16); classification as medical patient, surgical patient with trauma, or surgical patient without trauma according to the admitting diagnosis; and reason for initiating mechanical ventilation (17). The following baseline variables were recorded before randomization: SAPS II score; SOFA score; ODIN score; body temperature; leukocyte count; radiologic score (range, 0 to 12 according to the density of radiologic infiltration) (18); ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen (Pao 2/Fio 2); presence of shock, defined as systolic arterial pressure less than 90 mm Hg with signs of peripheral hypoperfusion or need for continuous infusion of vasopressor or inotropic agents (19); and presence of the acute respiratory distress syndrome, defined as the presence of a generalized pulmonary infiltrate and a lung injury score more than 2.5 (20); duration of previous mechanical ventilation; and use or no use of antibiotics. These baseline variables (except SAPS II score) were measured again 3, 7, 14, 21, and 28 days after the day of inclusion. All infections requiring specific therapeutic measures during the first 3 days after inclusion were recorded. Antibiotic use was recorded daily until day 28. Specimen Collection and Microbiological Processing Patients who received invasive management underwent fiberoptic bronchoscopy according to each centers protocol. Premedication, use of a short-acting neuromuscular blocking agent, and adjustment of Fio 2 to 95% or more were recommended; protected specimen brush, bronchoalveolar lavage, or both were performed at the investigators discretion. Processing of microbiological specimens has been described in detail elsewhere (10, 21). Briefly, recovered bronchoalveolar lavage fluid was divided into two samples: one for direct microscopic examination of cytocentrifuge preparations after Gram or modified Wright-Giemsa staining to determine the percentages of cells containing intracellular bacteria, and the other for quantitative cultures. The tip of the protected specimen brush was cut, dropped into 1 mL of sterile water, and vortexed for 1 minute; samples were examined directly and serially diluted for culture. The number of bacteria in the original specimens was estimated by colony counts and is expressed as CFU/mL. Patients in the invasive treatment group were considered to have ventilator-associated pneumonia if more than 5% of the cells in cytocentrifuge preparations of bronchoalveolar lavage fluid contained intracellular bacteria or at least one bacterial species grew at a significant concentration from the protected specimen brush sample ( 103 CFU/mL) or from bronchoalveolar lavage fluid ( 104 CFU/mL) (10, 22). In patients who received clinical treatment, endotracheal aspirates were collected sterilely by using a suction catheter in a mucus collector; secretions were aspirated without instilling saline. Aspirates were vortexed for 1 minute; Gram staining and qualitative aerobic cultures were performed for all patients. Definitions Inappropriate treatment, evaluated initially and at 3 days, was defined as the use of antibiotics to which at least one cultured isolate was resistant in vitro. For patients in the clinical management group, all pathogens grown in qualitative endotracheal aspirate cultures were considered for this analysis; for patients in the invasive management group, only pathogens cultured at significant concentrations were taken into account. Resistant bacteria were defined as ticarcillin-resistant Pseudomonas aeruginosa, Acinetobacter baumannii, and Stenotrophomonas maltophilia; extended-spectrum -lactamase-producing Enterobacteriaceae; and methicillin-resistant Staphylococcus aureus. We calculated the number of antibiotic-free days (days without antibiotic therapy) at 14 and 28 days after inclusion. For example, a patient who survived 28 days and received no antibiotics was assigned a value of 28. If antibiotics had been given for 10 days and the patient died on day 14, a value of 4 was assign

Hemodynamic effects of fluid loading in acute massive pulmonary embolism.

OBJECTIVE To assess the hemodynamic effects of fluid loading in patients with acute circulatory failure caused by acute massive pulmonary embolism (AMPE). DESIGN Prospective study. SETTING Respiratory critical care unit of a university hospital. PATIENTS Thirteen patients free of previous cardiopulmonary disease with angiographically proven AMPE (Miller index = 24 +/- 1), with acute circulatory failure defined by a cardiac index (CI) lower than 2.5 L/min/m2. INTERVENTION Infusion of 500 mL of dextran 40 over 20 mins. MEASUREMENTS AND MAIN RESULTS Fluid loading induced a substantial increase in right atrial pressure from 9 +/- 1 mm Hg to 17 +/- 1 mm Hg and in right ventricular end-diastolic volume index from 123 +/- 14 mL/m2 to 150 +/- 11 mL/m2 (p < .05 for both comparisons). The increase in right ventricular preload was associated with an increase in Cl from 1.6 +/- 0.1 to 2.0 +/- 0.1 L/min/m2 (p < .05), whereas right ventricular ejection fraction (15 +/- 3% at baseline vs. 16 +/- 3% after fluid loading) and total pulmonary vascular resistance index (1689 +/- 187 dyne x sec/cm5 x m2 at baseline vs. 1492 +/- 166 dyne x sec/ cm5 x m2 after fluid loading) remained unchanged. The increase in Cl induced by fluid loading was inversely correlated to baseline right ventricular end-diastolic volume index (r = -.89 ; p< .05). CONCLUSIONS These results suggest that fluid loading can improve hemodynamic status in patients with acute circulatory failure caused by AMPE.

Reduced breathing variability as a predictor of unsuccessful patient separation from mechanical ventilation.

Objectives:To compare descriptors of the breath-to-breath respiratory variability during a 60-min spontaneous breathing trial in patients successfully and unsuccessfully separated from the ventilator and the endotracheal tube and to assess the usefulness of these predictors in discriminating these two categories of patients. Design:Prospective observational study. Setting:Four general intensive care units in university hospitals. Patients:A total of 51 consecutive patients mechanically ventilated for >24 hrs. Interventions:None. Measurements and Main Results:Tidal volume, respiratory period, inspiratory time, expiratory time, mean inspiratory flow (tidal volume/inspiratory time), and duty cycle (inspiratory time/respiratory period) were obtained from the flow signal. Breath-by-breath variability was expressed in terms of their coefficients of variation (CV), the number of breaths among which a significant correlation was found (lag), and the autocorrelation coefficient between one breath and the following one. Five patients were excluded because of nonstationarity of the data, leaving 46 cases for analysis. Between-group comparison was conducted with the Mann-Whitney test, and a nonparametric classification and regression tree was used to identify variables discriminating “success” (n = 32) and “failure” patients (n = 14). All coefficients of variation were significantly higher in success patients, who also exhibited significantly less respiratory autocorrelation (shorter “short memory”). The classification and regression tree analysis allocated all success patients to a group defined by a coefficient of variation of tidal volume/inspiratory time of ≥19% and a coefficient of variation of inspiratory time/respiratory period of ≥10% that did not contain any failure patient. All failure patients belonged to a group with coefficient of variation of tidal volume/inspiratory time of <19%, a lag tidal volume of ≥11, and that contained no success patient. Conclusions:In intensive care unit patients undergoing a spontaneous breathing trial, breathing variability is greater in patients successfully separated from the ventilator and the endotracheal tube. Variability indices are sufficient to separate success from failure cases.

Clinically relevant diaphragmatic dysfunction after cardiac operations

Phrenic nerve injury and diaphragmatic dysfunction can be induced by cardiac operation. The clinical consequences are not well-established. We evaluated 13 consecutive patients over a 2-year period with unexplained and prolonged difficulties in weaning from mechanical ventilation. The mean time of measurement from the operation day was 31 +/- 19 days (range 8 to 78). With the same technique we also evaluated 12 control patients: four patients at day 1 after cardiac operation while they were still intubated; four normally convalescing patients at day 7 or 8 after cardiac operation; and four patients who required prolonged mechanical ventilation because of another identified cause after cardiac operation. Diaphragmatic function was evaluated at the bedside from esophageal and gastric pressure measurements. A low or negative ratio of gastric pressure swing to transdiaphragmatic pressure swing, indicative of diaphragm dysfunction, was found in all 13 patients (mean -0.39 +/- 0.64). The difference between the 13 patients and all control groups was found to be highly significant. Transdiaphragmatic pressure measured during a maximal voluntary inspiratory effort and transdiaphragmatic pressure measured during a short, sharp sniff were markedly diminished (28 +/- 18 cm H2O and 13 +/- 15 cm H2O, respectively) in the 13 patients, significantly different from values in the four control patients studied at day 7 or 8. Transdiaphragmatic pressure measured after magnetic stimulation in four patients was also markedly reduced (7 +/- 5 cm H2O) as compared with normal theoretic values. Aminophylline infusion had no effect on any of these parameters. In one of two patients evaluated a second time, about 5 weeks later, a marked improvement was observed. Estimating the prevalence of clinically relevant diaphragmatic dysfunction, we found it to be 0.5% when no topical cooling was used and 2.1% when iced slush with no insulation pad was added for myocardial protection (p < 0.005). The most striking finding was that the clinical course of the 13 patients was marked by severe intercurrent events, including cardiorespiratory arrest after early tracheal extubation in 5 patients, nosocomial pneumonia in 11, prolonged mechanical ventilation in all (58 +/- 41 days), and a fatal outcome in 3. We conclude that prolonged postoperative diaphragmatic dysfunction may cause severe life-threatening complications after cardiac operation and can be limited to some extent by avoiding the use of iced slush topical cooling of the heart.

Decreased ADAMTS-13 (A disintegrin-like and metalloprotease with thrombospondin type 1 repeats) is associated with a poor prognosis in sepsis-induced organ failure.

Objective:The inability to regulate the inflammatory response initiated upon infection leads to severe sepsis, characterized by widespread microvascular injury and thrombosis, organ ischemia, and dysfunction. A disintegrin-like and metalloprotease with thrombospondin type 1 repeats (ADAMTS)-13 regulates primary hemostasis by proteolyzing von Willebrand factor (VWF). Decreased ADAMTS-13 has been reported in disseminated intravascular coagulation due to severe sepsis. The present study investigates whether the sepsis-related dysregulation of endothelial activation leads to specific changes of ADAMTS-13. Design:Case-control study. Setting:Adult intensive care unit in a university hospital. Patients/Subjects:Three groups were studied: a case group of 30 patients with severe sepsis, a control group of 29 patients with comparable organ failure unrelated to sepsis, and 30 age- and gender-matched healthy subjects. Interventions:None. Measurements and Main Results:Significantly lower ADAMTS-13 activity was observed in patients with severe sepsis (43.2%; interquartile range, 32.7, 67.0) than in patients with organ failure unrelated to sepsis (67.8%; 57.4, 87.9; p < .05) and healthy subjects (105.6%; 87.2, 125.6; p < .001). Accordingly, ADAMTS-13 antigen was more decreased in patients with severe sepsis than in patients with organ failure unrelated to sepsis and healthy subjects. VWF antigen was higher in patients with severe sepsis than in patients with organ failure unrelated to sepsis and healthy subjects. We found strong negative correlations in severe sepsis but not in organ failure unrelated to sepsis, between ADAMTS-13 activity and 1) VWF antigen; 2) thrombomodulin; 3) interleukin-6; 4) Acute Physiology and Chronic Health Evaluation II score; 5) shock; 6) acute renal injury. Moreover, patients above the median of ADAMTS-13 activity presented a higher survival compared with those below the median in the patients with severe sepsis but not in the patients with organ failure unrelated to sepsis. In contrast, there was no significant association between VWF antigen and survival in either the severe sepsis group or the group with organ failure unrelated to sepsis. Conclusions:We observed low ADAMTS-13 activity and antigen in severe sepsis and in other conditions associated with organ dysfunction. ADAMTS-13 levels were significantly associated with differences in morbidity, mortality, and variables of inflammation and endothelial dysregulation only in severe sepsis patients. This suggests that ADAMTS-13 deficiency may have a pathophysiological relevance specific to severe sepsis.

Clinically significant gastrointestinal bleeding in critically ill patients with and without stress-ulcer prophylaxis

ObjectiveTo compare the rates of clinically significant gastrointestinal bleeding and the number of blood units and endoscopies required for gastrointestinal hemorrhage between patients receiving or not receiving stress-ulcer prophylaxis.DesignHistorical observational study comparing two consecutive periods: with (phase 1) and without stress-ulcer prophylaxis (phase 2).Design and settingA 17-bed intensive care unit in a university teaching hospital.PatientsIn phase 1 there were 736 patients and in phase 2 737. Those in the two phases were comparable in age and reason for admission; clinically significant gastrointestinal bleeding rates did not differ between the two phases, but patients in phase 2 were more severely ill.Measurements and resultsComparable numbers of blood units were transfused per bleeding patient in the two phases, especially for patients with significant gastrointestinal bleeding. During each phase 19 fibroscopies were performed for significant bleeding, and two patients required surgery. The clinically significant gastrointestinal bleeding rate and outcome did not differ in patients with at least one risk factor. Total expenditures directly related to gastrointestinal bleeding were similar during the two phases; the total cost incurred by stress-ulcer prophylaxis was estimated at €6700.ConclusionsOur results suggest that stress-ulcer prophylaxis does not influence the clinically significant gastrointestinal bleeding rate in intensive care unit patients or the cost of its management.

Safety and pharmacokinetics of an anti-PcrV PEGylated monoclonal antibody fragment in mechanically ventilated patients colonized with Pseudomonas aeruginosa: a randomized,double-blind, placebo-controlled trial.

Objective: The type III secretion system is an important Pseudomonas aeruginosa-virulence determinant in animal models of infection and in humans. Antibody-mediated inhibition of the PcrV protein, an essential component of this system, might abrogate the Pseudomonas aeruginosa ability to damage epithelial cells, neutrophils, and macrophages, thereby limiting its pathogenicity. The objective of the trial was to determine the safety, pharmacokinetics, and ability to prevent Pseudomonas aeruginosa ventilator–associated pneumonia of KB001, a recombinant, PEGylated, engineered, human Fab′ fragment that specifically binds to a Pseudomonas aeruginosa PcrV epitope and blocks its function. Design: Multicenter, randomized, placebo-controlled, double-blind, phase-2a trial. Setting: Ten intensive care units across France. Patients: Thirty-nine Pseudomonas aeruginosa-colonized, but not infected, mechanically ventilated patients. Interventions: Patients were randomized 1:1:1 to receive a single intravenous infusion of KB001, 3 mg/kg (n = 13) or 10 mg/kg (n = 14), or placebo (n = 12). Measurements and Main Results: The primary end points were KB001 safety and tolerability, assessed as treatment-related adverse-event frequency and severity. Secondary end points included serum and lung KB001 pharmacokinetics, and Pseudomonas aeruginosa pneumonia rate within 28 days of its infusion. KB001 was well tolerated and not immunogenic. The 3- and 10-mg/kg groups had respective maximum serum concentrations of 52,811–88,660 and 121,857–285,454 ng/mL, with mean elimination half-lives of 8.1 and 9.3 days. KB001 was detected in endotracheal aspirates from all patients receiving it, as early as day 1 and up to 28 days. Respective mean endotracheal aspirate/serum concentration ratios were 0.092 and 0.085 for the 3- and 10-mg/kg groups, who developed Pseudomonas aeruginosa pneumonia less frequently (33% and 31%, respectively) than placebo recipients (60%). Conclusions: KB001 was safe and well tolerated in this study, with a favorable pharmacokinetic profile and promising potential for reducing Pseudomonas aeruginosa pneumonia incidence in intensive care unit mechanically ventilated patients colonized with this bacterium.

Increased intensity of treatment and decreased mortality in elderly patients in an intensive care unit over a decade

Objectives:Data collected from two cohorts of patients aged ≥80 yrs and admitted to an intensive care unit in France were compared to determine whether intensive care unit care and survival had evolved from the 1990s to the 2000s. Design:Retrospective cohort study on patient data attained during intensive care unit stays. Setting:18-bed intensive care unit in an academic medical center. Patients:Two cohorts of patients aged ≥80 yrs, admitted to an intensive care unit at a 10-yr interval. Interventions:None. Measurements and Main Results:The first cohort comprised 348 patients admitted between January 1992 and December 1995, and the second cohort, 373 patients admitted between January 2001 and December 2004. There was no difference in age between the two cohorts, but patients in the second had significantly less history of functional limitation and significantly more acute illness (Simplified Acute Physiology Score II 43 ± 18 vs. 57 ± 25, respectively, p < .0001). Patients in the second cohort had a significantly higher Omega Score, had a higher occurrence of renal replacement therapy, and received vasopressors more frequently than the patients in the first cohort, even when adjusted for age, sex, Knaus classification, Simplified Acute Physiology Score II, and intensive care unit admission cause. Intensive care unit mortality was 65% and 64% for the first and second cohorts, respectively. In multivariate analysis (including age, Knaus classification, Simplified Acute Physiology Score II and first vs. second period) for association with intensive care unit survival, the 2001–2004 period was associated with a near tripling of chances of survival (odds ratio 2.9; 95% confidence interval, 1.92–4.47, p < .0001). Conclusions:The characteristics and intensity of treatment for elderly people admitted to the intensive care unit changed significantly over a decade. The intensity of treatments has increased over time and survival has improved over time as well. A potential link between increased treatment and improved survival in the elderly may be evoked.

Ultrasonographic Diagnostic Criterion for Severe Diaphragmatic Dysfunction After Cardiac Surgery

BACKGROUND Severe diaphragmatic dysfunction can prolong mechanical ventilation after cardiac surgery. An ultrasonographic criterion for diagnosing severe diaphragmatic dysfunction defined by a reference technique such as transdiaphragmatic pressure measurements has never been determined. METHODS Twenty-eight patients requiring mechanical ventilation > 7 days postoperatively were studied. Esophageal and gastric pressures were measured to calculate transdiaphragmatic pressure during maximal inspiratory effort and the Gilbert index, which evaluates the diaphragm contribution to respiratory pressure swings during quiet ventilation. Ultrasonography allowed measuring right and left hemidiaphragmatic excursions during maximal inspiratory effort. Best E is the greatest positive value from either hemidiaphragm. Twenty cardiac surgery patients with uncomplicated postoperative course were also evaluated with ultrasonography preoperatively and postoperatively. Measurements were performed in semirecumbent position. RESULTS Transdiaphragmatic pressure during maximal inspiratory effort was below normal value in 27 of the 28 patients receiving prolonged mechanical ventilation (median, 39 cm H(2)O; interquartile range [IQR] 28 cm H(2)O). Eight patients had Gilbert indexes <or= 0 indicating severe diaphragmatic dysfunction. Best E was lower in patients with Gilbert index <or= 0 than > 0 (30 mm; IQR, 10 mm; vs 19 mm; IQR, 7 mm, respectively; p = 0.001). Best E < 25 mm had a positive likelihood ratio of 6.7 (95% confidence interval [CI], 2.4 to 19) and a negative likelihood ratio of 0 (95% CI, 0 to 1.1) for having a Gilbert index <or= 0. None of the patients with uncomplicated course had Best E < 25 mm either preoperatively or postoperatively. CONCLUSIONS Ultrasonographic-based determination of hemidiaphragm excursions in patients requiring prolonged mechanical ventilation after cardiac surgery may help identify those with and without severe diaphragmatic dysfunction as defined by the Gilbert index.