Randomized, Placebo-controlled Trial of Inhaled Treprostinil for Patients at Risk for Acute Respiratory Distress Syndrome

Efficacy and safety of several common drugs in the treatment of acute respiratory distress syndrome: A systematic review and network meta-analysis

BACKGROUND

This study aimed to compare the effectiveness and safety of neuromuscular blockers, mesenchymal stem cells (MSC), and inhaled pulmonary vasodilators (IV) for acute respiratory distress syndrome through a network meta-analysis of randomized controlled trials (RCTs).

METHODS

We searched Chinese and English databases, including China National Knowledge Infrastructure, The Cochrane Library, PubMed, and EMbase, with no time restrictions. We conducted a network meta-analysis and reported the results according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. We included 27 clinical RCTs, all of which were two-arm trials, totaling 3492 patients. We selected 28-day mortality as the primary outcome measure, whereas 90-day mortality, ventilator-free days, and oxygenation served as secondary outcome measures for analysis and comparison.

RESULTS

We selected 3 treatment modalities and evaluated their clinical trials in comparison with the standard control group. For the 28-day in-hospital mortality, we included 21 RCTs, involving 2789 patients. Compared to standard treatment, neuromuscular blockers were associated with reduced 28-day hospital mortality (odds ratios [OR] 0.52, 95% confidence intervals [CI] (0.31, 0.88)), while IV and MSC were not associated with reduced hospital mortality (OR 0.89, 95% CI (0.50, 1.55); OR 0.90, 95% CI (0.49, 1.66)). In terms of 90-day mortality, days free of mechanical ventilation, and improvement in oxygenation, there were no significant differences compared to standard treatment with neuromuscular blockers, MSC, and IV.

CONCLUSION

Neuromuscular blockers significantly reduced the 28-day mortality rate in acute respiratory distress syndrome patients. However, in terms of 90-day mortality, ventilator-free days, oxygenation improvement, IV, MSC, and neuromuscular blockers did not significantly improve.

Study on the clinical characteristics, treatment, and outcome influencing factors of severe pneumonia complicated with ARDS

To investigate the clinical characteristics, treatment methods, and factors influencing the prognosis of patients with severe pneumonia complicated by Acute Respiratory Distress Syndrome (ARDS), aiming to provide references for clinical decision-making and improve patient outcomes. A retrospective analysis was conducted on 118 patients with severe pneumonia complicated by ARDS treated at our hospital from June 2018 to December 2022. Based on treatment outcomes, patients were divided into a death group (n = 75) and a survival group (n = 43). General data and clinical laboratory indicators, including blood urea nitrogen, serum creatinine, C-reactive protein, procalcitonin, arterial partial pressure of oxygen, and arterial partial pressure of carbon dioxide, were collected and compared between the 2 groups to identify independent factors affecting prognosis. Among the 118 patients, the mortality rate was 63.56%. Patients in the death group had a significantly higher average age (57.15 ± 13.38 years) and a higher proportion of severe ARDS (66.67%) compared to the survival group (40.02 ± 11.41 years, 30.23%, P < .001). The death group had significantly lower white blood cell counts (8.10 ± 1.64 × 109/L), oxygenation index (19.82 ± 2.29), and duration of mechanical ventilation (7.79 ± 2.11 days) compared to the Survival group (8.92 ± 1.22 × 109/L, 13.42 ± 1.82, 12.23 ± 3.05 days, P < .05). Conversely, the death group had significantly higher levels of blood urea nitrogen (6.87 ± 1.80 mmol/L), C-reactive protein (130.55 ± 50.28 mg/L), procalcitonin (5.50 ± 2.11 ng/mL), arterial partial pressure of carbon dioxide (41.12 ± 5.56 mm Hg), and a higher proportion of viral infections (48.00%) compared to the survival group (5.90 ± 1.72 mmol/L, 101.77 ± 55.56 mg/L, 3.98 ± 1.15 ng/mL, 35.59 ± 6.22 mm Hg, 27.91%, P < .05). Logistic regression analysis revealed that age (odds ratios [OR] = 1.990, 95% confidence interval [CI]: 1.306-3.033, P < .001), oxygenation index (OR = 1.426, 95% CI: 1.123-1.649, P < .001), and duration of mechanical ventilation (OR = 0.694, 95% CI: 0.557-0.864, P < .001) were independent factors influencing patient prognosis. This indicates that an increase in age and a decrease in oxygenation index are associated with a significantly higher risk of mortality, while shorter mechanical ventilation duration is related to poorer prognosis. Advanced age, lower oxygenation index, and shorter duration of mechanical ventilation are unfavorable prognostic factors in patients with severe pneumonia complicated by ARDS. These findings aid clinicians in identifying high-risk patients, optimizing treatment plans, and improving patient prognosis.

A Narrative Review on the Administration of Inhaled Prostaglandins in Critically Ill Adult Patients With Acute Respiratory Distress Syndrome

OBJECTIVE

To describe the effect of inhaled prostaglandins on both oxygenation and mortality in critically ill patients with acute respiratory distress syndrome (ARDS), with a focus on safety and efficacy in coronavirus disease 2019 (COVID-19)-associated ARDS and non-COVID-19 ARDS.

DATA SOURCES

A literature search of MEDLINE was performed using the following search terms: inhaled prostaglandins, inhaled epoprostenol, inhaled nitric oxide, ARDS, critically ill. All abstracts were reviewed.

STUDY SELECTION AND DATA EXTRACTION

Relevant English-language reports and studies conducted in humans between 1980 and June 2023 were considered.

DATA SYNTHESIS

Data regarding inhaled prostaglandins and their effect on oxygenation are limited but show a benefit in patients who respond to therapy, and data pertaining to their effect on mortality is scarce. Concerns exist regarding the formulation of inhaled epoprostenol (iEPO) utilized in addition to modes of medication delivery; however, the limited data surrounding their use have shown a reasonable safety profile. Other avenues and beneficial effects may exist with inhaled prostaglandins, such as use in COVID-19-associated ARDS or non-COVID-19 ARDS patients undergoing noninvasive mechanical ventilation or during patient transport.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

The use of inhaled prostaglandins can be considered in critically ill patients with COVID-19-associated ARDS or non-COVID-19 ARDS who are experiencing difficulties with oxygenation refractory to nonpharmacologic strategies.

CONCLUSIONS

The use of iEPO and other inhaled prostaglandins requires further investigation to fully elucidate their effects on clinical outcomes, but it appears these medications may have a potential benefit in COVID-19-associated ARDS and non-COVID-19 ARDS patients with refractory hypoxemia but with little effect on mortality.

Challenges in ARDS Definition, Management, and Identification of Effective Personalized Therapies

Over the last decade, the management of acute respiratory distress syndrome (ARDS) has made considerable progress both regarding supportive and pharmacologic therapies. Lung protective mechanical ventilation is the cornerstone of ARDS management. Current recommendations on mechanical ventilation in ARDS include the use of low tidal volume (VT) 4-6 mL/kg of predicted body weight, plateau pressure (PPLAT) < 30 cmH2O, and driving pressure (∆P) < 14 cmH2O. Moreover, positive end-expiratory pressure should be individualized. Recently, variables such as mechanical power and transpulmonary pressure seem promising for limiting ventilator-induced lung injury and optimizing ventilator settings. Rescue therapies such as recruitment maneuvers, vasodilators, prone positioning, extracorporeal membrane oxygenation, and extracorporeal carbon dioxide removal have been considered for patients with severe ARDS. Regarding pharmacotherapies, despite more than 50 years of research, no effective treatment has yet been found. However, the identification of ARDS sub-phenotypes has revealed that some pharmacologic therapies that have failed to provide benefits when considering all patients with ARDS can show beneficial effects when these patients were stratified into specific sub-populations; for example, those with hyperinflammation/hypoinflammation. The aim of this narrative review is to provide an overview on current advances in the management of ARDS from mechanical ventilation to pharmacological treatments, including personalized therapy.

Acute Respiratory Distress Syndrome and the Use of Inhaled Pulmonary Vasodilators in the COVID-19 Era: A Narrative Review

The Coronavirus disease (COVID-19) pandemic of 2019 has resulted in significant morbidity and mortality, especially from severe acute respiratory distress syndrome (ARDS). As of September 2022, more than 6.5 million patients have died globally, and up to 5% required intensive care unit treatment. COVID-19-associated ARDS (CARDS) differs from the typical ARDS due to distinct pathology involving the pulmonary vasculature endothelium, resulting in diffuse thrombi in the pulmonary circulation and impaired gas exchange. The National Institute of Health and the Society of Critical Care Medicine recommend lung-protective ventilation, prone ventilation, and neuromuscular blockade as needed. Further, a trial of pulmonary vasodilators is suggested for those who develop refractory hypoxemia. A review of the prior literature on inhaled pulmonary vasodilators in ARDS suggests only a transient improvement in oxygenation, with no mortality benefit. This narrative review aims to highlight the fundamental principles in ARDS management, delineate the fundamental differences between CARDS and ARDS, and describe the comprehensive use of inhaled pulmonary vasodilators. In addition, with the differing pathophysiology of CARDS from the typical ARDS, we sought to evaluate the current evidence regarding the use of inhaled pulmonary vasodilators in CARDS.

Pulse oximetry for the diagnosis and management of acute respiratory distress syndrome

The diagnosis of acute respiratory distress syndrome (ARDS) traditionally requires calculation of the ratio of partial pressure of arterial oxygen to fraction of inspired oxygen (PaO2/FiO2) using arterial blood, which can be costly and is not possible in many resource-limited settings. By contrast, pulse oximetry is continuously available, accurate, inexpensive, and non-invasive. Pulse oximetry-based indices, such as the ratio of pulse-oximetric oxygen saturation to FiO2 (SpO2/FiO2), have been validated in clinical studies for the diagnosis and risk stratification of patients with ARDS. Limitations of the SpO2/FiO2 ratio include reduced accuracy in poor perfusion states or above oxygen saturations of 97%, and the potential for reduced accuracy in patients with darker skin pigmentation. Application of pulse oximetry to the diagnosis and management of ARDS, including formal adoption of the SpO2/FiO2 ratio as an alternative to PaO2/FiO2 to meet the diagnostic criterion for hypoxaemia in ARDS, could facilitate increased and earlier recognition of ARDS worldwide to advance both clinical practice and research.

Treatment for acute respiratory distress syndrome in adults: A narrative review of phase 2 and 3 trials

INTRODUCTION

Ventilatory management and general supportive care of acute respiratory distress syndrome (ARDS) in the adult population have led to significant clinical improvements, but morbidity and mortality remain high. Pharmacologic strategies acting on the coagulation cascade, inflammation, oxidative stress, and endothelial cell injury have been targeted in the last decade for patients with ARDS, but only a few of these have shown potential benefits with a meaningful clinical response and improved patient outcomes. The lack of availability of specific pharmacologic treatments for ARDS can be attributed to its complex pathophysiology, different risk factors, huge heterogeneity, and difficult classification into specific biological phenotypes and genotypes.

AREAS COVERED

In this narrative review, we briefly discuss the relevance and current advances in pharmacologic treatments for ARDS in adults and the need for the development of new pharmacological strategies.

EXPERT OPINION

Identification of ARDS phenotypes, risk factors, heterogeneity, and pathophysiology may help to design clinical trials personalized according to ARDS-specific features, thus hopefully decreasing the rate of failed clinical pharmacologic trials. This concept is still under clinical investigation and needs further development.