Fibroproliferative phase of ARDS. Clinical findings and effects of corticosteroids

The Impact of Steroid Responder Status on Long-Term Outcomes in Critically Ill Patients With Acute Respiratory Distress Syndrome Receiving High-Dose Glucocorticoids

Background and objective High-dose intravenous pulsed glucocorticosteroids (GCS) are not part of the standard treatment in acute respiratory distress syndrome (ARDS), and the evidence supporting their use is conflicting. In clinical practice, however, they are used in specialist settings when clinico-patho-radiological features suggest a potentially steroid-responsive pattern, or as a last resort in cases where patients are unable to be weaned off mechanical ventilation. This study aimed to investigate if an early objective response to high-dose GCS treatment in selected critically ill patients is predictive of survival in ARDS. Methods This study involved a case series of 63 patients treated at a tertiary specialist respiratory ICU between 2009 and 2017 who received high-dose GCS for ARDS following a multidisciplinary board agreement. Patients were stratified according to the change in their modified lung injury score (mLIS) between days 0 and 10 following GCS initiation. Changes in mLIS (range: 0-4) were grouped as follows - full responders: ≥2, partial responders: ≥1 and <2, and non-responders: <1. Mortality on discharge and at 6, 12, 18, and 24 months post-ICU discharge was assessed for each group. Data were analysed using logistic regression and a receiver operating curve (ROC) to determine a statistically significant association between the change in mLIS and survival. Results Of the 63 patients, there were seven full responders, 12 partial responders, and 44 non-responders to high-dose GCS. Overall mortality at ICU discharge and 6, 12, 18 and 24 months post-discharge was 29/63 (46.0%), 33/63 (52.4%), 34/63 (54.0%), 34/63 (54.0%), and 35/63 (55.6%) respectively. Mortality was significantly lower in the partial and full-response groups than in the non-response group at all time frames. Logistic regression showed a significant association between the change in mLIS and survival (p<0.001), and a ROC demonstrated that categorising the change in mLIS was a good predictive model for survival (c-statistic 0.86). Conclusions Measuring the change in mLIS by day 10 following high-dose GCS administration for ARDS may be clinically useful in prognosticating such patients. Further research using mLIS as a measure of response to GCS, and larger datasets to enable the evaluation of prognostic factors, may assist clinicians in predicting which patients with persistent ARDS are likely to respond to GCS therapy.

Corticosteroids in ARDS

Acute respiratory distress syndrome (ARDS) is frequently associated with sepsis. ARDS and sepsis exhibit a common pathobiology, namely excessive inflammation. Corticosteroids are powerful anti-inflammatory agents that are routinely used in septic shock and in oxygen-dependent SARS-CoV-2 related acute respiratory failure. Recently, corticosteroids were found to reduce mortality in severe community-acquired pneumonia. Corticosteroids may therefore also have a role to play in the treatment of ARDS. This narrative review was undertaken following a PubMed search for English language reports published before January 2023 using the terms acute respiratory distress syndrome, sepsis and steroids. Additional reports were identified by examining the reference lists of selected articles and based on personnel knowledge of the authors of the field. High-quality research is needed to fully understand the role of corticosteroids in the treatment of ARDS and to determine the optimal timing, dosing and duration of treatment.

Pulmonary Cryptococcosis and Pulmonary Fibrosis: A Complication of COVID-19 Pneumonia

Acute respiratory distress syndrome (ARDS) and pulmonary fibrosis (PF) are increasingly identified as complications of coronavirus disease 2019 (COVID-19) infection, the latter being managed with tapering dose glucocorticoids. Studies have shown improved outcomes with steroid use in this subset of patients; however, the use of high doses of steroids predisposes these patients to develop various complications such as opportunistic infections. The incidence of pulmonary cryptococcosis (PC) in patients with post-COVID-19 PF is not known. Here, we discuss a middle-aged male, with no pulmonary comorbidities, who developed PC secondary to the immunocompromised state from high-dose steroid use for the management of post-COVID-19 PF.

P311 promotes type II transforming growth factor-β receptor mediated fibroblast activation and granulation tissue formation in wound healing

Background

P311, a highly conserved 8 kDa intracellular protein, has recently been reported to play an important role in aggravating hypertrophic scaring by promoting the differentiation and secretion of fibroblasts. Nevertheless, how P311 regulates the differentiation and function of fibroblasts to affect granulation tissue formation remains unclear. In this work, we studied the underlying mechanisms via which P311 affects fibroblasts and promotes acute skin wound repair.

Methods

To explore the role of P311, both in vitro and in vivo wound-healing models were used. Full-thickness skin excisional wounds were made in wild-type and P311^-/- C57 adult mice. Wound healing rate, re-epithelialization, granulation tissue formation and collagen deposition were measured at days 3, 6 and 9 after skin injury. The biological phenotypes of fibroblasts, the expression of target proteins and relevant signaling pathways were examined both in vitro and in vivo.

Results

P311 could promote the proliferation and differentiation of fibroblasts, enhance the ability of myofibroblasts to secrete extracellular matrix and promote cell contraction, and then facilitate the formation of granulation tissue and eventually accelerate skin wound closure. Importantly, we discovered that P311 acts via up-regulating the expression of type II transforming growth factor-β receptor (TGF-βRII) in fibroblasts and promoting the activation of the TGF-βRII-Smad signaling pathway. Mechanistically, the mammalian target of rapamycin signaling pathway is closely implicated in the regulation of the TGF-βRII-Smad pathway in fibroblasts mediated by P311.

Conclusions

P311 plays a critical role in activation of the TGF-βRII-Smad pathway to promote fibroblast proliferation and differentiation as well as granulation tissue formation in the process of skin wound repair.

Glucocorticoid therapy in respiratory illness: bench to bedside

Each year, hundreds of millions of individuals are affected by respiratory disease leading to approximately 4 million deaths. Most respiratory pathologies involve substantially dysregulated immune processes that either fail to resolve the underlying process or actively exacerbate the disease. Therefore, clinicians have long considered immune-modulating corticosteroids (CSs), particularly glucocorticoids (GCs), as a critical tool for management of a wide spectrum of respiratory conditions. However, the complex interplay between effectiveness, risks and side effects can lead to different results, depending on the disease in consideration. In this comprehensive review, we present a summary of the bench and the bedside evidence regarding GC treatment in a spectrum of respiratory illnesses. We first describe here the experimental evidence of GC effects in the distal airways and/or parenchyma, both in vitro and in disease-specific animal studies, then we evaluate the recent clinical evidence regarding GC treatment in over 20 respiratory pathologies. Overall, CS remain a critical tool in the management of respiratory illness, but their benefits are dependent on the underlying pathology and should be weighed against patient-specific risks.

Prolonged Methylprednisolone Therapy in the Fibro-Proliferative Phase of Acute Respiratory Distress Syndrome

Late-stage acute respiratory distress syndrome (ARDS), primarily associated with fibro-proliferative changes, may occur in many patients. This stage, where ARDS progresses to the point of being incurable, involves a complicated and long clinical course that may give rise to functional loss; it has therefore been a major focus of both preventive and therapeutic strategies. In the present case report, the successful use of prolonged methylprednisolone therapy in the fibro-proliferative phase of ARDS is described in a patient who developed pneumonia and secondary ARDS after terminating a pregnancy due to preeclampsia. Methylprednisolone therapy, which was initiated at a daily dosage of 1 mg/kg, was tapered down based on the clinical and radiologic status of the patient and was terminated at the end of the sixth month. Follow-up imaging studies and pulmonary function tests performed at the end of the first and sixth months showed marked improvements and the patient experienced no systemic adverse effects despite long-term steroid therapy.

Glucocorticoids for acute respiratory distress syndrome: A systematic review with meta-analysis and trial sequential analysis

BACKGROUND

Glucocorticoids are some of the most commonly used drugs for patients with acute respiratory distress syndrome (ARDS). However, the curative effect and side effects of glucocorticoids in treating patients with ARDS remain controversial.

METHODS

Three databases were searched until 2 July 2020, and randomized controlled trials (RCTs) that compared glucocorticoids versus other therapies in the treatment of ARDS were included in this meta-analysis. Trial sequential analysis (TSA) was conducted.

RESULTS

A total of 14 RCTs with 1362 ARDS patients were assessed. Overall, no statistically significant effect was found on mortality between the glucocorticoid group and the control group of ARDS patients. In the subgroup analysis, no benefit of glucocorticoids for ARDS on mortality was found in trials stratified according to low versus high risk of bias or with vs. without a loading dose. As for the dose and length of therapy, no statistically significant effect was found on mortality with high-dose, short-course glucocorticoid therapy. However, lower-dose and longer-course therapy with glucocorticoids was found to decrease the mortality of ARDS patients (lower dose: RR = 0.69, 95% CI = 0.51-0.93, P = .02; longer-course therapy: RR = 0.60, 95% CI = 0.37-0.99, P = .04). The TSA showed that more trials are needed to confirm the results.

CONCLUSIONS

Longer- and lower-dose glucocorticoid treatment may improve the prognosis of ARDS patients, but RCTs with higher quality and larger sample sizes are needed to further clarify the clinical effects of glucocorticoids on ARDS.

Adverse Outcomes Associated With Corticosteroid Use in Critical COVID-19: A Retrospective Multicenter Cohort Study

Corticosteroid is commonly used to reduce damage from inflammatory reactions in coronavirus disease 2019 (COVID-19). We aim to determine the outcomes of corticosteroid use in critically ill COVID-19 patients. Ninety six critically ill patients, hospitalized in 14 hospitals outside Wuhan from January 16 to March 30, 2020 were enrolled in this study. Among 96 critical patients, 68 were treated with corticosteroid (CS group), while 28 were not treated with corticosteroids (non-CS group). Multivariable logistic regression were performed to determine the possible correlation between corticosteroid use and the treatment outcomes. Forty-six (68%) patients in the CS group died compared to six (21%) of the non-CS group. Corticosteroid use was also associated with the development of ARDS, exacerbation of pulmonary fibrosis, longer hospital stay and virus clearance time. On admission, no difference in laboratory findings between the CS and the non-CS group was observed. After corticosteroid treatment, patients treated with corticosteroids were associated with higher counts of white blood cells, neutrophils, neutrophil-to-lymphocyte ratio, alanine aminotransferase level and Sequential Organ Failure Assessment score. In conclusion, corticosteroid use in critically ill COVID-19 patients was associated with a much higher case fatality rate. Frequent incidence of liver injury and multi-organ failure in corticosteroid treated patients may have contributed to the adverse outcomes. The multi-organ failure is likely caused by more persistent SARS-CoV-2 infection and higher viral load, due to the inhibition of immune surveillance by corticosteroid.

Exploration of therapeutic role of montelukast and dexamethasone combination against paraquat induced inhalational toxicity

OBJECTIVES

To explore the therapeutic role of a single dose combination of montelukast (MON) and dexamethasone (DXM) through intra-peritoneal route against paraquat (PQ)-intoxicated experimental Wistar rats.

METHODS

In vivo the survival rate was investigated following the administration of both MON and DXM in PQ exposed rats. Lungs parameters including enhanced pause (Penh), tidal volume (TV) and breath per minute (BPM) were determined using the whole body plethysmograph (WBP). Further chest imaging and histopathological studies were conducted to evaluate the lungs injury. In vivo the antioxidant activity was carried out by determining the levels of catalase (SOD), superoxide dismutase (CAT) and glutathione peroxidase (GSH-Px). Lungs tissue concentration of different proinflammatory cytokines like IL-1β, IL-6, TGF-β1 and TNF-α was also determined. Finally, expression of NF-kB and p-NF-kB was investigated by western blot.

RESULTS

Results of survival rate and levels of lungs parameters indicated therapeutic potential of combination treatment of MON and DXM. Protective activity on lungs was reflected in chest imaging and histopathological investigations. Moreover, combination treatment exhibited significant increased levels of all anti-oxidant parameters. Significant decrease in the levels of IL-1β; IL-6; TGF-β1 and TNF-α was also observed with the combination treatment of MON and DXM. Evidence of significant down regulation of NF-kB and phospho-NF-kB was also found with the combination treatment of MON and DXM.

CONCLUSIONS

Given the advantage of therapeutic synergism activity of MON and DXM, it may be used in the prophylaxis of PQ-intoxication following clinical trials.

Improved oxygenation following methylprednisolone therapy and survival in paediatric acute respiratory distress syndrome

Background

Methylprednisolone remains a commonly used ancillary therapy for paediatric acute respiratory distress syndrome (PARDS), despite a lack of level 1 evidence to justify its use. When planning prospective trials it is useful to define response to therapy and to identify if there is differential response in certain patients, i.e. existence of ‘responders’ and ‘non responders’ to therapy. This retrospective, observational study carried out in 2 tertiary referral paediatric intensive care units aims to characterize the change in Oxygen Saturation Index, following the administration of low dose methylprednisolone in a cohort of patients with PARDS, to identify what proportion of children treated demonstrated response, whether any particular characteristics predict response to therapy, and to determine if a positive response to corticosteroids is associated with reduced Paediatric Intensive Care Unit mortality.

Methods

All patients who received prolonged, low dose, IV methylprednisolone for the specific indication of PARDS over a 5-year period (2011–2016) who met the PALICC criteria for PARDS at the time of commencement of steroid were included (n = 78).OSI was calculated four times per day from admission until discharge from PICU (or death). Patients with ≥20% improvement in their mean daily OSI within 72 hours of commencement of methylprednisolone were classified as ‘responders’. Primary outcome measure was survival to PICU discharge.

Results

Mean OSI of the cohort increased until the day of steroid commencement then improved thereafter. 59% of patients demonstrated a response to steroids. Baseline characteristics were similar between responders and non-responders. Survival to PICU discharge was significantly higher in ‘responders’ (74% vs 41% OR 4.14(1.57–10.87) p = 0.004). On multivariable analysis using likely confounders, response to steroid was an independent predictor of survival to PICU discharge (p = 0.002). Non-responders died earlier after steroid administration than responders (p = 0.003).

Conclusions

An improvement in OSI was observed in 60% of patients following initiation of low dose methylprednisolone therapy in this cohort of patients with PARDS. Baseline characteristics fail to demonstrate a difference between responders and non-responders. A 20% improvement in OSI after commencement of methylprednisolone was independently predictive of survival, Prospective trials are needed to establish if there is a benefit from this therapy.

Moderate to Severe Acute Respiratory Distress Syndrome Management Strategies: A Narrative Review

Acute respiratory distress syndrome (ARDS) remains a common complication associated with significant negative outcomes in critically ill patients. Lung-protective mechanical ventilation strategies remain the cornerstone in the management of ARDS. Several therapeutic options are currently available including fluid management, neuromuscular blocking agents, prone positioning, extracorporeal membrane oxygenation, corticosteroids, and inhaled pulmonary vasodilating agents (prostacyclins and nitric oxide). Unfortunately, an evidence-based, standard-of-care approach in managing ARDS beyond lung-protective ventilation remains elusive, contributing to significant variability in clinical practice. Although the optimal therapeutic strategy for managing moderate to severe ARDS remains extremely controversial, therapies supported with more robust clinical evidence should be considered first. The purpose of this narrative review is to discuss the published clinical evidence for both pharmacologic and nonpharmacologic management strategies in adult patients with moderate to severe ARDS as well as to discuss practical considerations for implementation.

Ventilator-induced lung injury and lung mechanics

Mechanical ventilation applies physical stresses to the tissues of the lung and thus may give rise to ventilator-induced lung injury (VILI), particular in patients with acute respiratory distress syndrome (ARDS). The most dire consequences of VILI result from injury to the blood-gas barrier. This allows plasma-derived fluid and proteins to leak into the airspaces where they flood some alveolar regions, while interfering with the functioning of pulmonary surfactant in those regions that remain open. These effects are reflected in commensurately increased values of dynamic lung elastance (EL ), a quantity that in principle is readily measured at the bedside. Recent mathematical/computational modeling studies have shown that the way in which EL varies as a function of both time and positive end-expiratory pressure (PEEP) reflects the nature and degree of lung injury, and can even be used to infer the separate contributions of volutrauma and atelectrauma to VILI. Interrogating such models for minimally injurious regimens of mechanical ventilation that apply to a particular lung may thus lead to personalized approaches to the ventilatory management of ARDS.

Corticosteroids in ARDS: The Never-Ending Story

This feature examines the impact of pharmacologic interventions on the treatment of the critically ill patient — an area of health care that has become increasingly complex. Recent advances in drug therapy (including evolving and controversial data) for adult intensive-care-unit patients will be reviewed and assessed in terms of clinical, humanistic, and economic outcomes.

A review of associated controversies surrounding glucocorticoid use in veterinary emergency and critical care

OBJECTIVE

To review the literature in human and veterinary medicine regarding the indications for, efficacy of, and controversies surrounding glucocorticoid (GC) administration in the emergency and critical care (ECC) setting, and to provide an overview of the most commonly used synthetic GC formulations.

MEDICATIONS

Synthetic GCs vary in GC and mineralocorticoid potency, hypothalamic pituitary axis suppression, duration of action, route of administration, and clinical indication for use. Some of the GC compounds commonly used in human and veterinary ECC include hydrocortisone, prednisone, methylprednisolone, and dexamethasone.

INDICATIONS FOR USE

GCs are used in human and veterinary ECC for a variety of disorders including anaphylaxis, acute lung injury/acute respiratory distress syndrome, septic shock, and spinal cord injury. Evidence for morbidity or mortality benefit with administration of GC within these populations exists; however, data are sparse and often conflicting.

ADVERSE EFFECTS AND CONTRAINDICATIONS

Routine use of GC in some conditions such as trauma, hemorrhagic shock, and traumatic brain injury is likely contraindicated. GC use has been associated with hyperglycemia, pneumonia, urinary tract infection, gastrointestinal ulceration, or increased mortality in some populations.

Evaluating the efficacy of dexamethasone in the treatment of patients with persistent acute respiratory distress syndrome: study protocol for a randomized controlled trial

Background

Although much has evolved in our understanding of the pathogenesis and factors affecting outcome of patients with acute respiratory distress syndrome (ARDS), still there is no specific pharmacologic treatment for ARDS. Several clinical trials have evaluated the utility of corticoids but none of them has demonstrated a definitive benefit due to small sample sizes, selection bias, patient heterogeneity, and time of initiation of treatment or duration of therapy. We postulated that adjunctive treatment of persistent ARDS with intravenous dexamethasone might change the pulmonary and systemic inflammatory response and thereby reduce morbidity, leading to a decrease in duration of mechanical ventilation and a decrease in mortality.

Methods/design

This is a prospective, multicenter, randomized, controlled trial in 314 patients with persistent moderate/severe ARDS. Persistent ARDS is defined as maintaining a PaO₂/FiO₂ ≤ 200 mmHg on PEEP ≥ 10 cmH₂O and FiO₂ ≥ 0.5 after 24 hours of routine intensive care. Eligible patients will be randomly allocated to two arms: (i) conventional treatment without dexamethasone, (ii) conventional treatment plus dexamethasone. Patients in the dexamethasone group will be treated with a daily dose of 20 mg iv from day 1 to day 5, and 10 mg iv from day 6 to day 10. Primary outcome is the number of ventilator-free days, defined as days alive and free from mechanical ventilation at day 28 after intubation. Secondary outcome is all-cause mortality at day 60 after enrollment.

Discussion

This study will be the largest randomized controlled clinical trial to assess the role of dexamethasone in patients with persistent ARDS.

Trial registration

Registered on 21 November 2012 as DEXA-ARDS at ClinicalTrials.gov website (NCT01731795).

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1456-4) contains supplementary material, which is available to authorized users.

Pediatric Acute Hypoxemic Respiratory Failure: Management of Oxygenation

Acute hypoxemic respiratory failure (AHRF) is one of the hallmarks of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), which are caused by an inflammatory process initiated by any of a number of potential systemic and/or pulmonary insults that result in heterogeneous disruption of the capillary-pithelial interface. In these critically sick patients, optimizing the management of oxygenation is crucial. Physicians managing pediatric patients with ALI or ARDS are faced with a complex array of options influencing oxygenation. Certain treatment strategies can influence clinical outcomes, such as a lung protective ventilation strategy that specifies a low tidal volume (6 mL/kg) and a plateau pressure limit (30 cm H2O). Other strategies such as different levels of positive end expiratory pressure, altered inspiration to expiration time ratios, recruitment maneuvers, prone positioning, and extraneous gases or drugs may also affect clinical outcomes. This article reviews state-of-the-art strategies on the management of oxygenation in acute hypoxemic respiratory failure in children.

The role of steroids following major trauma

This article reviews the indications and evidence for the administration of steroids to patients who have suffered significant trauma. Uncontroversial indications are rare. In spinal cord injury steroids are often given but the practical benefits are questionable. The case for treatment in head injury is unproven. Consideration should be given to treating all those patients who develop acute respiratory distress syndrome (ARDS), although treatment should be deferred to the later (fibroproliferative) stages. The role of steroids in sepsis is complicated and, although steroid administration can have dramatic effects on vasopressor requirements, convincing evidence for mortality reduction is not available.

Which patients with ARDS benefit from lung biopsy?

A central tenet of caring for patients with ARDS is to treat the underlying cause, be it sepsis, pneumonia, or removal of an offending toxin. Identifying the risk factor for ARDS has even been proposed as essential to diagnosing ARDS. Not infrequently, however, the precipitant for acute hypoxemic respiratory failure is unclear, and this raises the question of whether a histologic lung diagnosis would benefit the patient. In this review, we consider the historic role of pathology in establishing a diagnosis of ARDS and the published experience of surgical and transbronchial lung biopsy in patients with ARDS. We reflect on which pathologic diagnoses influence treatment and suggest a patient-centric approach to weigh the risks and benefits of a lung biopsy for critically ill patients who may have ARDS.

Steroids for acute respiratory distress syndrome?

The development and severity of acute respiratory distress syndrome (ARDS) are closely related to dysregulated inflammation, and the duration of ARDS and eventual outcomes are related to persistent inflammation and abnormal fibroproliferation. Corticosteroids are potent modulators of inflammation and inhibitors of fibrosis that have been used since the first description of ARDS in attempts to improve outcomes. There is no evidence that corticosteroids prevent the development of ARDS among patients at risk. High-dose and short-course treatment with steroids does not improve the outcomes of patients with ARDS. Additional studies are needed to recommend treatment with steroids for ARDS.

Acute lung injury and fibrosis in a baboon model of Escherichia coli sepsis

Sepsis-induced inflammation of the lung leads to acute respiratory distress syndrome (ARDS), which may trigger persistent fibrosis. The pathology of ARDS is complex and poorly understood, and the therapeutic approaches are limited. We used a baboon model of Escherichia coli sepsis that mimics the complexity of human disease to study the pathophysiology of ARDS. We performed extensive biochemical, histological, and functional analyses to characterize the disease progression and the long-term effects of sepsis on the lung structure and function. Similar to humans, sepsis-induced ARDS in baboons displays an early inflammatory exudative phase, with extensive necrosis. This is followed by a regenerative phase dominated by proliferation of type 2 epithelial cells, expression of epithelial-to-mesenchymal transition markers, myofibroblast migration and proliferation, and collagen synthesis. Baboons that survived sepsis showed persistent inflammation and collagen deposition 6-27 months after the acute episodes. Long-term survivors had almost double the amount of collagen in the lung as compared with age-matched control animals. Immunostaining for procollagens showed persistent active collagen synthesis within the fibroblastic foci and interalveolar septa. Fibroblasts expressed markers of transforming growth factor-β and platelet-derived growth factor signaling, suggesting their potential role as mediators of myofibroblast migration and proliferation, and collagen deposition. In parallel, up-regulation of the inhibitors of extracellular proteases supports a deregulated matrix remodeling that may contribute to fibrosis. The primate model of sepsis-induced ARDS mimics the disease progression in humans, including chronic inflammation and long-lasting fibrosis. This model helps our understanding of the pathophysiology of fibrosis and the testing of new therapies.

Always cleave up your mess: targeting collagen degradation to treat tissue fibrosis

Pulmonary fibrosis is a vexing clinical problem with no proven therapeutic options. In the normal lung there is continuous collagen synthesis and collagen degradation, and these two processes are precisely balanced to maintain normal tissue architecture. With lung injury there is an increase in the rate of both collagen production and collagen degradation. The increase in collagen degradation is critical in preventing the formation of permanent scar tissue each time the lung is exposed to injury. In pulmonary fibrosis, collagen degradation does not keep pace with collagen production, resulting in extracellular accumulation of fibrillar collagen. Collagen degradation occurs through both extracellular and intracellular pathways. The extracellular pathway involves cleavage of collagen fibrils by proteolytic enzyme including the metalloproteinases. The less-well-described intracellular pathway involves binding and uptake of collagen fragments by fibroblasts and macrophages for lysosomal degradation. The relationship between these two pathways and their relevance to the development of fibrosis is complex. Fibrosis in the lung, liver, and skin has been associated with an impaired degradative environment. Much of the current scientific effort in fibrosis is focused on understanding the pathways that regulate increased collagen production. However, recent reports suggest an important role for collagen turnover and degradation in regulating the severity of tissue fibrosis. The objective of this review is to evaluate the roles of the extracellular and intracellular collagen degradation pathways in the development of fibrosis and to examine whether pulmonary fibrosis can be viewed as a disease of impaired matrix degradation rather than a disease of increased matrix production.

The harmful effect of prolonged high-dose methylprednisolone in acute lung injury

Although many literatures have shown that prolonged high-dose administration of corticosteroids is hazardous and not indicated to therapy acute lung injury (ALI), there is little information on the harmful effect of prolonged high-dose corticosteroids in acute lung injury. In this study, we aimed to investigate the effect of prolonged high-dose methylprednisolone (MPL) on ALI and improve knowledge regarding the appropriate use of corticosteroids in ALI. The different doses of MPL (3, 30, 180mg·kg(-1)) were given via tail vein injection 1h after the first time LPS administration and were daily administrated for 14days. Lung tissues and lavage samples were isolated for biochemical determinations and histological measurements at 12h, 7days and 14days after LPS administration. Single administration of 180mg·kg(-1) MPL decreased the lung injury score, wet-to-dry ratio, the total cell numbers and level of procollagen type III in BALF at 12h after LPS challenge. However, prolonged therapy with 180mg·kg (-1) MPL for 7days and 14days decreased the number of AMs in BALF and increased the above-mentioned indexes. These results suggested that the prolonged high-dose MPL has harmful effects to treat LPS-induced ALI in rats.

Low-dose steroids in adult septic shock: results of the Surviving Sepsis Campaign

OBJECTIVE

The Surviving Sepsis Campaign (SSC) developed guidelines and treatment bundles for the administration of steroids in adult septic shock. However, it is not clear how this has affected clinical practice or patient outcome.

DESIGN AND SETTING

The SSC has developed an extensive database to assess the overall effect of its guidelines on clinical practice and patient outcome. This analysis focuses on one particular element of the SSC's management bundle, namely, the administration of low-dose steroids in adult septic shock. This analysis was conducted on data submitted from January 2005 through March 2010 including 27,836 subjects at 218 sites.

MAIN RESULTS

A total of 17,847 (of the total 27,836) patients in the database required vasopressor therapy despite fluid resuscitation and therefore met the eligibility criteria for receiving low-dose steroids. A total of 8,992 patients (50.4 %) received low-dose steroids for their septic shock. Patients in Europe (59.4 %) and South America (51.9 %) were more likely to be prescribed low-dose steroids compared to their counterparts in North America (46.2 %, p < 0.001). The adjusted hospital mortality was significantly higher (OR 1.18, 95 % CI 1.09-1.23, p < 0.001) in patients who received low-dose steroids compared to those who did not. There was still an association with increased adjusted hospital mortality with low-dose steroids even if they were prescribed within 8 h (OR 1.23, 95 % CI 1.13-1.34, p < 0.001).

CONCLUSIONS

Steroids were commonly administered in the treatment of septic shock in this subset analysis of the Surviving Sepsis Campaign database. However, this was associated with an increase in adjusted hospital mortality.

[Corticosteroid administration for acute respiratory distress syndrome : therapeutic option?]

Despite a number of clinical trials there is still controversy about the role of corticosteroid therapy in acute respiratory distress syndrome (ARDS). In addition recent meta-analyses differed markedly in the conclusions. This review is intended to provide a short practical guide for the clinician. Based on the available literature, high-dose and pre-emptive administration of corticosteroids is hazardous and not indicated. A low-dose corticosteroid regime given for 4 weeks may potentially be helpful and can be considered in acute or unresolved ARDS in less than 14 days after onset of ARDS, if a close infection surveillance program is available, if neuromuscular blockade can be avoided and if a stepwise dose reduction of corticosteroids is performed. The total daily dose at the beginning of treatment should not exceed 2 mg/kg body weight (BW) methylprednisolone.

Protective Effect of the Fruit Hull of Gleditsia sinensis on LPS-Induced Acute Lung Injury Is Associated with Nrf2 Activation

The fruit hull of Gleditsia sinensis (FGS) has been prescribed as a traditional eastern Asian medicinal remedy for the treatment of various respiratory diseases, but the efficacy and underlying mechanisms remain poorly characterized. Here, we explored a potential usage of FGS for the treatment of acute lung injury (ALI), a highly fatal inflammatory lung disease that urgently needs effective therapeutics, and investigated a mechanism for the anti-inflammatory activity of FGS. Pretreatment of C57BL/6 mice with FGS significantly attenuated LPS-induced neutrophilic lung inflammation compared to sham-treated, inflamed mice. Reporter assays, semiquantitative RT-PCR, and Western blot analyses show that while not affecting NF-κB, FGS activated Nrf2 and expressed Nrf2-regulated genes including GCLC, NQO-1, and HO-1 in RAW 264.7 cells. Furthermore, pretreatment of mice with FGS enhanced the expression of GCLC and HO-1 but suppressed that of proinflammatory cytokines in including TNF-α and IL-1β in the inflamed lungs. These results suggest that FGS effectively suppresses neutrophilic lung inflammation, which can be associated with, at least in part, FGS-activating anti-inflammatory factor Nrf2. Our results suggest that FGS can be developed as a therapeutic option for the treatment of ALI.

Glucocorticoids in the treatment of acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is characterized by local inflammation and an intense systemic inflammatory reaction. Glucocorticoid administration has been suggested due to their anti-inflammatory properties. However, results from the initial studies of glucocorticoids in ARDS, which evaluated high-dose and short-term treatments, were negative. More recent studies have evaluated the effect of lower doses of glucocorticoids administered over longer periods, but the results thus far have been inconclusive.

Pathophysiology of acute respiratory distress syndrome. Glucocorticoid receptor-mediated regulation of inflammation and response to prolonged glucocorticoid treatment

Based on molecular mechanisms and physiologic data, a strong association has been established between dysregulated systemic inflammation and progression of ARDS. In ARDS patients, glucocorticoid receptor-mediated down-regulation of systemic inflammation is essential to restore homeostasis, decrease morbidity and improve survival and can be significantly enhanced with prolonged low-to-moderate dose glucocorticoid treatment. A large body of evidence supports a strong association between prolonged glucocorticoid treatment-induced down-regulation of the inflammatory response and improvement in pulmonary and extrapulmonary physiology. The balance of the available data from controlled trials provides consistent strong level of evidence (grade 1B) for improving patient-centered outcomes. The sizable increase in mechanical ventilation-free days (weighted mean difference, 6.58 days; 95% CI, 2.93 -10.23; P<0.001) and ICU-free days (weighted mean difference, 7.02 days; 95% CI, 3.20-10.85; P<0.001) by day 28 is superior to any investigated intervention in ARDS. The largest meta-analysis on the subject concluded that treatment was associated with a significant risk reduction (RR=0.62, 95% CI: 0.43-0.91; P=0.01) in mortality and that the in-hospital number needed to treat to save one life was 4 (95% CI 2.4-10). The balance of the available data, however, originates from small controlled trials with a moderate degree of heterogeneity and provides weak evidence (grade 2B) for a survival benefit. Treatment decisions involve a tradeoff between benefits and risks, as well as costs. This low cost highly effective therapy is familiar to every physician and has a low risk profile when secondary prevention measures are implemented.

Corticosteroids and ARDS: A review of treatment and prevention evidence

To systematically review the role of corticosteroids in prevention of acute respiratory distress syndrome (ARDS) in high-risk patients, and in treatment of established ARDS. Primary articles were identified by English-language Pubmed/MEDLINE, Cochrane central register of controlled trials, and Cochrane systemic review database search (1960–June 2009) using the MeSH headings: ARDS, adult respiratory distress syndrome, ARDS, corticosteroids, and methylprednisolone (MP). The identified studies were reviewed and information regarding role of corticosteroids in prevention and treatment of ARDS was evaluated. Nine trials have evaluated the role of corticosteroid drugs in management of ARDS at various stages. Of the 9, 4 trials evaluated role of corticosteroids in prevention of ARDS, while other 5 trials were focused on treatment after variable periods of onset of ARDS. Trials with preventive corticosteroids, mostly using high doses of MP, showed negative results with patients in treatment arm, showing higher mortality and rate of ARDS development. While trials of corticosteroids in early ARDS showed variable results, somewhat, favoring use of these agents to reduce associated morbidities. In late stage of ARDS, these drugs have no benefits and are associated with adverse outcome. Use of corticosteroids in patients with early ARDS showed equivocal results in decreasing mortality; however, there is evidence that these drugs reduce organ dysfunction score, lung injury score, ventilator requirement, and intensive care unit stay. However, most of these trials are small, having a significant heterogeneity regarding study design, etiology of ARDS, and dosage of corticosteroids. Further research involving large-scale trials on relatively homogeneous cohort is necessary to establish the role of corticosteroids for this condition.

Nonventilatory strategies for patients with life-threatening 2009 H1N1 influenza and severe respiratory failure

Severe respiratory failure (including acute lung injury and acute respiratory distress syndrome) caused by 2009 H1N1 influenza infection has been reported worldwide. Refractory hypoxemia is a common finding in these patients and can be challenging to manage. This review focuses on nonventilatory strategies in the advanced treatment of severe respiratory failure and refractory hypoxemia such as that seen in patients with severe acute respiratory distress syndrome attributable to 2009 H1N1 influenza. Specific modalities covered include conservative fluid management, prone positioning, inhaled nitric oxide, inhaled vasodilatory prostaglandins, and extracorporeal membrane oxygenation and life support. Pharmacologic strategies (including steroids) investigated for the treatment of severe respiratory failure are also reviewed.

Pharmacological treatments for acute respiratory distress syndrome

PURPOSE OF REVIEW

Studies of the pharmacologic management of acute respiratory distress syndrome (ARDS) have yielded conflicting results. The purpose of this review is to discuss recent pharmacologic trials in ARDS, using the conceptual framework of ARDS as a heterogeneous disease.

RECENT FINDINGS

Whereas most drug trials in ARDS have been negative, some studies suggest that targeting therapies at subgroups of patients may be successful. Proposed subgroups include early versus late-phase ARDS, direct versus indirect lung injury, and patients with altered coagulation. Corticosteroids have beneficial short-term effects when given at low or moderate doses sooner than 2 weeks but appear to be harmful if initiated later and are of unclear benefit if lung protective ventilation is also used. Surfactant may be helpful in patients with direct lung injury. Anticoagulants and vasodilators may have a greater chance for success in the subset of patients with vascular disease and a high dead-space fraction may identify such a population.

SUMMARY

ARDS is a heterogeneous syndrome. Failure to target subgroups more likely to benefit from specific therapies may be one explanation for largely disappointing trial results so far.

Prolonged exposure to sphingosine 1-phosphate receptor-1 agonists exacerbates vascular leak, fibrosis, and mortality after lung injury

Sphingosine 1-phosphate (S1P) is a key endogenous regulator of the response to lung injury, maintaining endothelial barrier integrity through interaction with one of its receptors, S1P(1). The short-term administration of S1P or S1P(1) receptor agonists enhances endothelial monolayer barrier function in vitro, and attenuates injury-induced vascular leak in the lung and other organ systems in vivo. Although S1P(1) agonists bind to and activate S1P(1), several of these agents also induce receptor internalization and degradation, and may therefore act as functional antagonists of S1P(1) after extended exposure. Here we report on the effects of prolonged exposure to these agents in bleomycin-induced lung injury. We demonstrate that repeated administration of S1P(1) agonists dramatically worsened lung injury after bleomycin challenge, as manifested by increased vascular leak and mortality. Consistent with these results, prolonged exposure to S1P(1) agonists in vitro eliminated the ability of endothelial cell monolayers to respond appropriately to the barrier-protective effects of S1P, indicating a loss of normal S1P-S1P(1) signaling. As bleomycin-induced lung injury progressed, continued exposure to S1P(1) agonists also resulted in increased pulmonary fibrosis. These data indicate that S1P(1) agonists can act as functional antagonists of S1P(1) on endothelial cells in vivo, which should be considered in developing these agents as therapies for vascular leak syndromes. Our findings also support the hypothesis that vascular leak is an important component of the fibrogenic response to lung injury, and suggest that targeting the S1P-S1P(1) pathway may also be an effective therapeutic strategy for fibrotic lung diseases.

Low-dose dexamethasone alleviates lipopolysaccharide-induced acute lung injury in rats and upregulates pulmonary glucocorticoid receptors

BACKGROUND AND OBJECTIVE

The major causes of mortality among patients who survive acute lung injury/ARDS (ALI/ARDS) are due to the extensive tissue remodelling and fibrosis. Use of high-dose glucocorticoids to reduce these inflammatory and fibroproliferative responses has been shown to do more harm than good. Recently, Meduri et al. found that the early use of low-dose prolonged methylprednisolone in patients with severe ALI/ARDS significantly relieved the systemic inflammatory response and improved pulmonary and extrapulmonary organ function. This study investigated the therapeutic effect of low-dose dexamethasone (Dex) on inflammation and fibrosis in LPS-induced ALI in rats and its influence on the expression of the pulmonary glucocorticoid receptor (GR).

METHODS

Eighty Wistar rats were randomly divided into four groups: a control group (intraperitoneal normal saline injection (5 mL/kg) throughout experiment, n = 24); the LPS model group (LPS injection (5 mg/kg) for 3 days and normal saline thereafter, n = 24); the LPS + Dex group (LPS injection for 3 days and Dex solution (5 mg/kg) thereafter, n = 16); and the Dex group (normal saline injection (5 mL/kg) for 3 days and Dex solution (5 mg/kg) thereafter, n = 16). Levels of tumor necrosis factor-alpha, matrix metallopeptidase-9 and procollagen N-terminal propeptide type I in BAL fluid were examined by ELISA on the third, seventh and fourteenth days after injection. Pulmonary hydroxyproline content was measured and histological examination was performed with haematoxylin-eosin and Victoria blue-ponceau. Pulmonary distribution of GR-positive cells was examined immunohistochemically, and expression of GR mRNA and protein was determined by RT-PCR and western blot analysis.

RESULTS

Histological assessments showed that pulmonary fibrosis occurred in parallel with inflammation in the rat ALI model. Compared with the LPS group, the inflammation and fibrosis parameters were significantly improved in the LPS + Dex group at different periods after injection (P < 0.05 or P < 0.01), although parameters in the LPS + Dex group were not as good as those of the control group. GR mRNA and protein expression in the LPS + Dex group were markedly higher than that of the LPS group on the seventh and the fourteenth days (both P < 0.01). Western blotting showed that Dex also promoted the nuclear translocation of GR protein.

CONCLUSION

Low-dose Dex can reduce pulmonary inflammation and fibrosis after LPS-induced ALI in rats and can elevate GR expression in the lung, probably through upregulating GR levels and promoting the nuclear translocation of GR protein.

Establishing the use of melatonin as an adjuvant therapeutic against paraquat-induced lung toxicity in rats

It is well known that the intake of paraquat (PQ) causes severe tissue injury leading to numerous fatalities. Considering that the main target for PQ toxicity is the lung and involves the production of reactive oxygen and nitrogen species, transcription factors and inflammatory cytokines, it may be hypothesized that the combination of a potent antiinflammatory and antioxidant agent may counteract more of PQ's effects than an antiinflammatory agent alone. For this purpose, combination of dexamethasone (Dex) and melatonin (Mel) was compared with Dex alone. A total of 40 male Wistar albino rats were divided into four groups as control, PQ, Dex only, and Dex plus Mel. The animals were given intraperitoneally a toxic dose of 19 mg/kg PQ dissolved in 1 ml saline. Control animals were injected with the same amount of saline only. A dose of 1 mg/kg Dex was administered 2 hrs after PQ administration. In the combination treatment group, 20 mg/kg Mel was given with Dex. All drugs were given every 12 hrs for a total of six doses. Five animals in PQ group and three animals in Dex only group died by the end of the study. No deaths occurred in the Dex+Mel group. Dex exerted improvements in several oxidative and antioxidative parameters. However, combination treatment provided beneficial effects against PQ toxicity far greater than Dex alone. This difference was also apparent when tissues were histologically compared. In conclusion, Mel exhibited strong additive beneficial effects with Dex and can be considered as a safe treatment modality against PQ toxicity.

Role of open-lung biopsy in acute respiratory distress syndrome

PURPOSE OF REVIEW

When classic examinations such as bronchoalveolar lavage are not contributory in the etiologic diagnosis of unresolving acute respiratory distress syndrome, surgical lung biopsy would appear to be useful to determine the specific cause, particularly infection or postaggressive fibrosis, which could benefit from an adapted treatment.

RECENT FINDINGS

Postaggressive pulmonary fibrosis is a possible evolution for unresolving acute respiratory distress syndrome and its association with a poor prognosis has been demonstrated. The administration of corticoids would make it possible to improve certain ventilatory parameters as well as the prognosis in the fibroproliferation stage. No clinical or usual microbiological criterion can confirm both the existence of fibrosis and nosocomial pneumonia. Biological markers for fibrosis such as procollagen III are not validated to confirm the appearance of a postaggressive fibrosis. A recent study has shown that surgical lung biopsy performed in patients with unresolving acute respiratory distress syndrome led to a therapeutic modification in 78% of the cases and made it possible to avoid empiric corticotherapy in nearly 50% of the cases considering the absence of fibrosis.

SUMMARY

Surgical lung biopsy could be proposed for patients with unresolving acute respiratory distress syndrome after 7-10 days of evolution despite well-conducted initial treatment when the etiology of acute respiratory distress syndrome has not been confirmed or when the appearance of postaggressive fibrosis is suspected.

Clinical Aspects of Acute Lung Insufficiency (ALI/TRALI)

SUMMARY: Acute respiratory distress syndrome (ARDS) is a common clinical disorder caused by a variety of direct and indirect injuries to the lung, characterized by alveolar epithelial and endothelial injury resulting in damage to the pulmonary alveolar-capillary barrier. The cardinal clinical feature of ARDS, refractory arterial hypoxemia, is the result of protein-rich alveolar edema with impaired surfactant function, due to vascular leakage and vascular dysfunction with consequently impaired matching of ventilation to perfusion. Since its first description in 1967, considerable knowledge concerning the pathogenesis of ARDS has been obtained, however, a plethora of questions remain. Better understanding of the pathophysiology of ARDS has lead to the development of novel therapies, pharmacological strategies, and advances in mechanical ventilation. However, lung-protective ventilation is the only confirmed option in ARDS management improving survival, and few other therapies have translated into improved oxygenation or reduced ventilation time. But despite improvement in our understanding of the therapy and supportive care for patients with ARDS, mortality remains high. It is the purpose of this article to provide an overview of the definition, clinical features, and pathogenesis of ARDS, and to present and discuss therapeutic options currently available in order to effectively treat this severe disorder.

Recent developments in the management of acute respiratory distress syndrome in adults

PURPOSE

Recent developments in the management of acute respiratory distress syndrome (ARDS) in adults are reviewed.

SUMMARY

Corticosteroids have been extensively studied in ARDS; however, they have not demonstrated clear benefit in patients with ARDS. Some trials have found increased complications and mortality related to corticosteroid use. The use of conservative fluid management has been associated with significant reductions in morbidity, highlighting the need to avoid fluid over-administration in patients with ARDS. A number of ventilatory strategies have also been studied. Studies have found that higher positive end-expiratory pressure settings do not appear to be harmful in patients with ARDS. In an effort to prevent alveolar overdistention, low tidal volume and plateau pressure ventilation is increasingly being used in patients with acute lung injury (ALI). Given the increasing evidence supporting the use of lower tidal volume ventilation, this strategy has become the new standard of care in patients with suspected ALI and ARDS. No clear benefit has been shown in the treatment of ARDS with nitric oxide and surfactant. Prostaglandins and acetylcysteine are not considered useful in the treatment of ARDS, while no conclusions can be drawn regarding the benefits of albuterol on mortality in patients with ARDS. The use of prone positioning should be discouraged in the treatment of ARDS based on its associated risks.

CONCLUSION

Early administration of moderate-dosage corticosteroids likely helps decrease the time of ventilator dependence and duration of intensive care unit stay. Conservative fluid management and low tidal volume ventilation are becoming increasingly widespread in the management of patients with ARDS. Nitric oxide, surfactant, prostaglandins, albuterol, acetylcysteine, and prone positioning have not been shown to be beneficial in the treatment of ARDS.

Do glucocorticoids decrease mortality in acute respiratory distress syndrome? A meta-analysis

BACKGROUND AND OBJECTIVES

Glucocorticoids have been shown to improve survival when used in patients with septic shock. The aim of this study was to analyse the role of glucocorticoids in decreasing mortality in acute respiratory distress syndrome (ARDS) both in the acute and the fibroproliferative phases.

METHODS

We searched the MEDLINE database for relevant studies published between 1980 and 2006, and included studies if the study design was a randomized controlled trial or observational study (comparing historical controls). The study population included patients with ARDS treated with glucocorticoids. We calculated the odds ratio and 95% confidence intervals (CI) for the outcome of mortality.

RESULTS

Six trials met the inclusion criteria; three investigated the role of steroids in early stage disease (n = 300) and three investigated the role of steroids in late stage disease (n = 235). The odds of glucocorticoids decreasing mortality in patients with early ARDS were 0.57 (95% CI: 0.25-1.32) with a number needed to treat of 10 for benefit (818 harm to 5 benefit) whereas the odds of glucocorticoids decreasing mortality in patients with late ARDS was 0.58 (95% CI: 0.22-1.53) with a number needed to treat of 15 for harm (6 harm to 21 benefit). However, there was significant heterogeneity.

CONCLUSIONS

Current evidence does not support a role for corticosteroids in the management of ARDS in either the early or late stages of the disease. More research is required to establish the role of steroids in specific subgroups of patients with severe sepsis and early ARDS who have relative adrenal insufficiency and patients with late ARDS 7-14 days after the onset of disease.

Acute lung injury and the acute respiratory distress syndrome: a clinical review

Acute respiratory distress syndrome and acute lung injury are well defined and readily recognised clinical disorders caused by many clinical insults to the lung or because of predispositions to lung injury. That this process is common in intensive care is well established. The mainstay of treatment for this disorder is provision of excellent supportive care since these patients are critically ill and frequently have coexisting conditions including sepsis and multiple organ failure. Refinements in ventilator and fluid management supported by data from prospective randomised trials have increased the methods available to effectively manage this disorder.

A contributive result of open-lung biopsy improves survival in acute respiratory distress syndrome patients

OBJECTIVE

The impact of a contributive result of open-lung biopsy on the outcome of patients with acute respiratory distress syndrome (ARDS) has not been extensively investigated. The aim of this study was therefore to determine the rate of contributive open-lung biopsy and whether it improved the prognosis of ARDS patients.

DESIGN

Prospective study conducted during an 8-yr period.

SETTING

A 14-bed medico-surgical intensive care unit and a 12-bed medical intensive care unit from the same hospital.

PATIENTS

One hundred open-lung biopsies were performed in 100 patients presenting ARDS.

INTERVENTIONS

Open-lung biopsy was performed after > or = 5 days of evolution of ARDS when there was no improvement in the respiratory status despite negative microbiological samples cultures and potential indication for corticosteroid treatment.

MEASUREMENTS AND MAIN RESULTS

Ten patients presented a mechanical complication following open-lung biopsy (two pneumothoraces and eight moderate air leaks). The unique independent factor associated with this complication was the minute ventilation when open-lung biopsy was performed (odds ratio, 1.20; 95% confidence interval, 1.03-1.41; p = .02). Fibrosis was noted in 53 patients but was associated with an infection in 29 of these 53 patients (55%). A contributive result of open-lung biopsy (defined as the addition of a new drug) was noted in 78 patients. Simplified Acute Physiology Score II was the only independent predictive factor of a contributive open-lung biopsy (odds ratio, 0.96; 95% confidence interval, 0.92-0.99; p = .04). Survival was higher in patients with a contributive open-lung biopsy (67%) than in patients in whom open-lung biopsy results did not modify the treatment (14%) (p < .001). The factors predicting survival were a contributive result of open-lung biopsy, female gender, and the Organ System Failures score the day of open-lung biopsy.

CONCLUSIONS

The present study shows that open-lung biopsy provided a contributive result in 78% of ARDS patients with a negative bronchoalveolar lavage. Survival of ARDS patients improved when open-lung biopsy was contributive.

Therapy for late-phase acute respiratory distress syndrome

Prolonged hypoxemic respiratory failure and evidence of lung organization and fibrosis are features of an ARDS subgroup that is variably identified as "late," "persistent," or "fibroproliferative" ARDS. Early reports suggested that patients with late ARDS had a high mortality unless treated with corticosteroids. A large recent study with improved methodology has demonstrated that despite improvements of pulmonary physiology, corticosteroids do not change mortality of patients who continue to meet ARDS criteria 7 to 28 days after onset of acute lung injury. Additionally, there is no compelling evidence that persistent ARDS confers a higher mortality than that of ALI/ARDS. Observational and interventional studies are needed to increase understanding of the incidence, best management, and outcomes of patients with persistent ARDS.