Introduction: Acute respiratory distress syndrome (ARDS) has heterogeneous etiologies, rapid progressive change and a high mortality rate. To improve the outcome of ARDS, accurate diagnosis is essential to the application of effective early treatment. The present study investigated the clinical effects and safety of open lung biopsy (OLB) in patients with early-stage ARDS of suspected non-infectious origin. Methods: We undertook a retrospective study of 41 patients with early-stage ARDS (defined as one week or less after intubation) who underwent OLB in two medical intensive care units of a tertiary care hospital from 1999 to 2005. Data analyzed included baseline characteristics, complication rate, pathological diagnoses, treatment alterations, and hospital survival. Results: The age of patients was 55 ± 17 years (mean ± SD). The average ratio of arterial partial pressure of oxygen (PaO₂) to fraction of inspired oxygen (FiO₂) was 116 ± 43 mmHg (mean ± SD) at biopsy. Seventeen patients (41%) were immunocompromised. Postoperative complications occurred in 20% of patients (8/41). All biopsies provided a pathological diagnosis with a diagnostic yield of 100%. Specific pathological diagnoses were made for 44% of patients (18/41). Biopsy findings led to an alteration of treatment modality in 73% of patients (30/41). The treatment alteration rate was higher in patients with nonspecific diagnoses than in patients with specific diagnoses (p = 0.0024). Overall mortality was 50% (21/41) and was not influenced by age, gender, pre-OLB oxygenation, complication rate, pathological results, and alteration of treatment. There was no surgery-related mortality. The survival rate for immunocompromised patients was better than that for immunocompetent patients (71% versus 33%; p = 0.0187) in this study. Conclusion: Our retrospective study suggests that OLB was a useful and acceptably safe diagnostic procedure in some selected patients with early-stage ARDS.

BACKGROUND: The functional status and outcomes in patients with prolonged mechanical ventilation (PMV) are often limited by poor endurance and pulmonary mechanics, which result from the primary diseases or prolonged time bedridden. We evaluate the impact of exercise training on pulmonary mechanics, physical functional status, and hospitalization outcomes in PMV patients. METHODS: Twenty-seven subjects with PMV in our respiratory care center (RCC) were divided randomly into an exercise training group ( n = 12) and a control group ( n = 15). The exercise program comprised 10 sessions of exercise training. The measurement of pulmonary mechanics and physical functional status (Functional Independence Measurement and Barthel index) were performed pre-study and post-study. The hospitalization outcomes included: days of mechanical ventilation, hospitalization days, and weaning and mortality rates during RCC stay. RESULTS: The training group had significant improvement in tidal volume (143.6 mL vs 192.5 mL, P = .02) and rapid shallow breathing index after training (162.2 vs 110.6, P = .009). No significant change was found in the control group except respiratory rate. Both groups had significant improvement in functional status during the study. However, the training group had greater changes in FIM score than the control group (44.6 vs 34.2, P = .024). The training group also had shorter RCC stay and higher weaning and survival rates than the control group, although no statistical difference was found. CONCLUSIONS: Subjects with PMV in our RCC demonstrated significant improvement in pulmonary mechanics and functional status after exercise training. The application of exercise training may be helpful for PMV patients to improve hospitalization outcomes.

Introduction: Lung fibrosis, reduced lung compliance, and severe hypoxemia found in patients with acute lung injury often result in a need for the support of mechanical ventilation. High-tidal-volume mechanical ventilation can increase lung damage and fibrogeneic activity but the mechanisms regulating the interaction between high tidal volume and lung fibrosis are unclear. We hypothesized that high-tidal-volume ventilation increased pulmonary fibrosis in acute lung injury via the serine/threonine kinase-protein kinase B (Akt) and mitogen-activated protein kinase pathways. Methods: After 5 days of bleomycin administration to simulate acute lung injury, male C57BL/6 mice, weighing 20 to 25 g, were exposed to either high-tidal-volume mechanical ventilation (30 ml/kg) or low-tidal-volume mechanical ventilation (6 ml/kg) with room air for 1 to 5 hours. Results: High-tidal-volume ventilation induced type I and type III procollagen mRNA expression, microvascular permeability, hydroxyproline content, Masson's trichrome staining, S100A4/fibroblast specific protein-1 staining, activation of Akt and extracellular signal-regulated kinase (ERK) 1/2, and production of macrophage inflammatory protein-2 and 10 kDa IFNγ-inducible protein in a dose-dependent manner. High-tidal-volume ventilation-induced lung fibrosis was attenuated in Akt-deficient mice and in mice with pharmacologic inhibition of ERK1/2 activity by PD98059. Conclusion: We conclude that high-tidal-volume ventilation-induced microvascular permeability, lung fibrosis, and chemokine production were dependent, in part, on activation of the Akt and ERK1/2 pathways.

Introduction: Positive pressure ventilation with large tidal volumes has been shown to cause release of cytokines, including macrophage inflammatory protein-2 (MIP-2), a functional equivalent of human IL-8, and neutrophil infiltration. Hyperoxia has been shown to increase ventilator-induced lung injury, but the mechanisms regulating interaction between a large tidal volume and hyperoxia are unclear. We hypothesized that large tidal volume ventilation using hyperoxia would increase MIP-2 production and neutrophil infiltration via the serine/threonine kinase/protein kinase B (Akt) pathway and the endothelial nitric oxide synthase (eNOS) pathway. Methods: C57BL/6 mice were exposed to large tidal volume (30 ml/kg) mechanical ventilation with room air or hyperoxia for 1–5 hours. Results: Large tidal volume ventilation using hyperoxia induced neutrophil migration into the lung, MIP-2 production, and Akt and eNOS activation in a time-dependent manner. Both the large tidal volume ventilation of Akt mutant mice and the pharmacological inhibition of Akt with LY294002 attenuated neutrophil sequestration, MIP-2 protein production, and Akt and eNOS activation. Conclusion: We conclude that hyperoxia increased large tidal volume-induced MIP-2 production and neutrophil influx through activation of the Akt and eNOS pathways.

Introduction: Dysregulation of coagulation and local fibrinolysis found in patients with acute lung injury often results in the need for the support of mechanical ventilation. High-tidal-volume mechanical ventilation can increase lung damage and suppression of fibrinolytic activity, but the mechanisms are unclear. We hypothesized that subcutaneous injections of unfractionated heparin and enoxaparin would decrease neutrophil infiltration, lung edema, and plasminogen-activator inhibitor-1 (PAI-1) production in mice exposed to high-tidal-volume ventilation. Methods: Male C57BL/6 mice, weighing 20 to 25 g, were exposed to either high-tidal-volume (30 ml/kg) or low-tidal-volume (6 ml/kg) mechanical ventilation with room air for 1 to 5 hours after 200 IU/kg or 400 IU/kg unfractionated heparin and 4 mg/kg or 8 mg/kg enoxaparin administration. Nonventilated mice served as a control group. Evan blue dye, lung wet- to dry-weight ratio, histopathologic grading of epithelium, myeloperoxidase, and gene expression of PAI-1 were measured. The expression of PAI-1 was studied by immunohistochemistry. Results: High-tidal-volume ventilation induced increased microvascular permeability, neutrophil influx, PAI-1 mRNA expression, production of PAI-1 protein, and positive staining of PAI-1 in epithelium in a dose-dependent manner. Lung injury induced by high-tidal-volume ventilation was attenuated with PAI-1-deficient mice and pharmacologic inhibition of PAI-1 activity by low-dose unfractionated heparin and enoxaparin. Conclusions: We conclude that high-tidal-volume mechanical ventilation increased microvascular permeability, neutrophil influx, lung PAI-1 mRNA expression, production of active PAI-1. The deleterious effects were attenuated by low-dose unfractionated heparin or enoxaparin treatment. Understanding the protective mechanism of unfractionated heparin and enoxaparin related to the reduction of PAI-1 may afford further knowledge of the effects of mechanical forces in the lung and development of possible therapeutic strategies involved in acute lung injury.

Background/Objective: Death in intensive care units (ICUs) may increase bereaved family members’ risk for posttraumatic stress disorder (PTSD). However, posttraumatic stress-related symptoms (hereafter as PTSD symptoms) and their precipitating factors were seldom examined among bereaved family members and primarily focused on associations between PTSD symptoms and patient/family characteristics. We aimed to investigate the course and predictors of clinically significant PTSD symptoms among family members of deceased ICU patients by focusing on modifiable quality indicators for end-of-life ICU care.Method: In this longitudinal observational study, 319 family members of deceased ICU patients were consecutively recruited from medical ICUs from two Taiwanese medical centers. PTSD symptoms were assessed at 1, 3, 6, and 13 months post-loss using the Impact of Event Scale-Revised (IES-R). Family satisfaction with end-of-life care in ICUs was assessed at 1 month post-loss. End-of-life care received in ICUs was documented over the patient’s ICU stay. Predictors for developing clinically significant PTSD symptoms (IES-R score ≥ 33) were identified by multivariate logistic regression with generalized estimating equation modeling.Results: The prevalence of clinically significant PTSD symptoms decreased significantly over time (from 11.0% at 1 month to 1.6% at 13 months post-loss). Longer ICU stays (adjusted odds ratio [95% confidence interval] = 1.036 [1.006, 1.066]), financial insufficiency (3.166 [1.159, 8.647]), and reported use of pain medications (3.408 [1.230, 9.441]) by family members were associated with a higher likelihood of clinically significant PTSD symptoms among family members during bereavement. Stronger perceived social support (0.937 [0.911, 0.965]) and having a Do-Not-Resuscitate (DNR) order issued before the patient’s death (0.073 [0.011, 0.490]) were associated with a lower likelihood of clinically significant PTSD symptoms. No significant association was observed for family members’ satisfaction with end-of-life care (0.988 [0.944, 1.034]) or decision-making in ICUs (0.980 [0.944, 1.018]).Conclusions: The likelihood of clinically significant PTSD symptoms among family members decreased significantly over the first bereavement year and was lower when a DNR order was issued before death. Enhancing social support and facilitating a DNR order may reduce the trauma of ICU death of a beloved for family members at risk for developing clinically significant PTSD symptoms.