Pharmacologic Treatments for Acute Respiratory Distress Syndrome

Adjunctive Therapies in Acute Respiratory Distress Syndrome

Despite significant advances in understanding acute respiratory distress syndrome (ARDS), mortality rates remain high. The appropriate use of adjunctive therapies can improve outcomes, particularly for patients with moderate to severe hypoxia. In this review, the authors discuss the evidence basis behind prone positioning, recruitment maneuvers, neuromuscular blocking agents, corticosteroids, pulmonary vasodilators, and extracorporeal membrane oxygenation and considerations for their use in individual patients and specific clinical scenarios. Because the heterogeneity of ARDS poses challenges in finding universally effective treatments, an individualized approach and continued research efforts are crucial for optimizing the utilization of adjunctive therapies and improving patient outcomes.

Management of Neuromuscular Blocking Agents in Critically Ill Patients with Lung Diseases

The use of neuromuscular blocking agents (NMBAs) is common in the intensive care unit (ICU). NMBAs have been used in critically ill patients with lung diseases to optimize mechanical ventilation, prevent spontaneous respiratory efforts, reduce the work of breathing and oxygen consumption, and avoid patient-ventilator asynchrony. In patients with acute respiratory distress syndrome (ARDS), NMBAs reduce the risk of barotrauma and improve oxygenation. Nevertheless, current guidelines and evidence are contrasting regarding the routine use of NMBAs. In status asthmaticus and acute exacerbation of chronic obstructive pulmonary disease, NMBAs are used in specific conditions to ameliorate patient-ventilator synchronism and oxygenation, although their routine use is controversial. Indeed, the use of NMBAs has decreased over the last decade due to potential adverse effects, such as immobilization, venous thrombosis, patient awareness during paralysis, development of critical illness myopathy, autonomic interactions, ICU-acquired weakness, and residual paralysis after cessation of NMBAs use. The aim of this review is to highlight current knowledge and synthesize the evidence for the effects of NMBAs for critically ill patients with lung diseases, focusing on patient-ventilator asynchrony, ARDS, status asthmaticus, and chronic obstructive pulmonary disease.

Signaling pathways and potential therapeutic targets in acute respiratory distress syndrome (ARDS)

Acute respiratory distress syndrome (ARDS) is a common condition associated with critically ill patients, characterized by bilateral chest radiographical opacities with refractory hypoxemia due to noncardiogenic pulmonary edema. Despite significant advances, the mortality of ARDS remains unacceptably high, and there are still no effective targeted pharmacotherapeutic agents. With the outbreak of coronavirus disease 19 worldwide, the mortality of ARDS has increased correspondingly. Comprehending the pathophysiology and the underlying molecular mechanisms of ARDS may thus be essential to developing effective therapeutic strategies and reducing mortality. To facilitate further understanding of its pathogenesis and exploring novel therapeutics, this review provides comprehensive information of ARDS from pathophysiology to molecular mechanisms and presents targeted therapeutics. We first describe the pathogenesis and pathophysiology of ARDS that involve dysregulated inflammation, alveolar-capillary barrier dysfunction, impaired alveolar fluid clearance and oxidative stress. Next, we summarize the molecular mechanisms and signaling pathways related to the above four aspects of ARDS pathophysiology, along with the latest research progress. Finally, we discuss the emerging therapeutic strategies that show exciting promise in ARDS, including several pharmacologic therapies, microRNA-based therapies and mesenchymal stromal cell therapies, highlighting the pathophysiological basis and the influences on signal transduction pathways for their use.

Rapid access to icetexane diterpenes: Their protective effects against lipopolysaccharides-induced acute lung injury via PI3K/AKT/NF-κB axis in macrophages

Acute lung injury (ALI) is a life-threatening disease with limited therapeutic options available in clinic. Development of novel strategies and drugs for anti-ALI therapy are urgently needed. In this study, a facile synthesis of 21 icetexane diterpenes and derivatives with widely-varied oxidation states, particularly the taxamairins that are otherwise challenging to access, were developed from the readily available carnosic acid. Further explorations of their biological implications led to the identification of taxamairin B (6) as a potent anti-inflammatory agent by decreasing the gene expressions of proinflammatory cytokines (TNF-α, IL-1β and IL-6), as well as mitigating NO and ROS production, within LPS-induced RAW264.7 cells. Taxamairin B (6, 25 mg/kg) also exerted significant protective effects against in LPS-induced ALI in mice. Mechanistic insights drawn from the transcriptomic analysis revealed that taxamairin B (6) down-regulated the PI3K-AKT pathway, along with the suppression of the nuclear translocation of NF-κB. This study not only paves a new pathway to taxamairins, but also provides novel drug leads for the development of anti-inflammatory agents with unique mode of actions.

Oxygenation target in acute respiratory distress syndrome

Determining oxygenation targets in acute respiratory distress syndrome (ARDS) remains a challenge. Although oxygenation targets have been used since ARDS was first described, they have not been investigated in detail. However, recent retrospective and prospective trials have evaluated the optimal oxygenation threshold in patients admitted to the general intensive care unit. In view of the lack of prospective data, clinicians continue to rely on data from the few available trials to identify the optimal oxygenation strategy. Assessment of the cost-benefit ratio of the fraction of inspired oxygen (FiO₂) to the partial pressure of oxygen in the arterial blood (PaO₂) is an additional challenge. A high FiO₂ has been found to be responsible for respiratory failure and deaths in numerous animal models. Low and high PaO₂ values have also been demonstrated to be potential risk factors in experimental and clinical situations. The findings from this literature review suggest that PaO₂ values ranging between 80 mmHg and 90 mmHg are acceptable in patients with ARDS. The costs of rescue maneuvers needed to reach these targets have been discussed. Several recent papers have highlighted the risk of disagreement between arterial oxygen saturation (SaO₂) and peripheral oxygen saturation (SpO₂) values. In order to avoid discrepancies and hidden hypoxemia, SpO₂ readings need to be compared with those of SaO₂. Higher SpO₂ values may be needed to achieve the recommended PaO₂ and SaO₂ values.

Meta-Analysis of the Effect of Glucocorticoids on Adult Acute Respiratory Distress Syndrome

Objectives

The aim of this study is to investigate the effect of glucocorticoids in adult patients with acute respiratory distress syndrome (ARDS) by meta-analysis.

Methods

PubMed, Cochrane Library, Embase, CNKI, Wanfang Database, and Chinese Biomedical literature database were searched. A randomized controlled trial (RCTS) on glucocorticoid therapy in adult patients with ARDS was conducted from the time of database construction to December 2021. The content is about the randomized controlled trial (RCT) of glucocorticoid treatment for adult patients with ARDS, without limiting the dose and course of glucocorticoid treatment. The quality of the included RCTS was evaluated by using the bias risk assessment tool of the Cochrane Collaboration network, and the basic information, clinical features, and target outcomes of the literature were extracted. The effects of glucocorticoids on mortality and oxygenation index (PaO₂/FiO₂) in adult ARDS patients were evaluated by meta-analysis.

Results

A total of 1,441 ARDS patients in 10 RCTs were finally included, including 734 patients in the glucocorticoid treatment group (hormone group) and 707 patients in the conventional treatment group (control group). The 10 studies included have a good overall design and high quality. Compared with controls, glucocorticoid use was significantly associated with a decrease in mortality in adult ARDS patients (relative risk (RR) = 0.73, 95% confidence interval (95% CI) = 0.59–0.90, P = 0.003). Analysis showed that glucocorticoids significantly reduced the mortality in ARDS patients treated with medium and low doses of steroids (RR = 0.73, 95% CI = 0.58–0.92, P = 0.007). In patients with early administration of steroids, intervention with glucocorticoids was significantly associated with the decreased mortality in adult ARDS patients compared with controls (RR = 0.74, 95% CI 0.56–0.99, P = 0.04). Among patients with more than 7 days of hormone therapy, treatment with glucocorticoids was significantly associated with decreased mortality in adult ARDS patients (RR = 0.66, 95% CI = 0.50–0.88, P = 0.005) compared with controls. Glucocorticoids tended to improve PaO₂/FiO₂ in adult ARDS patients compared with controls, but the difference was not statistically significant (weighted mean difference (WMD) = 11.60, 95% = CI = 15.02–38.22, P = 0.39).

Conclusion

Glucocorticoid therapy can reduce mortality in adult ARDS patients, and the benefit is more pronounced in patients with medium- and low-dose hormone therapy, early hormone administration, and hormone therapy for more than 7 days. However, no improvement in PaO₂/FiO₂ by glucocorticoid treatment was found, which needs to be confirmed by further studies.

Antioxidants as Therapeutic Agents in Acute Respiratory Distress Syndrome (ARDS) Treatment-From Mice to Men

Acute respiratory distress syndrome (ARDS) is a major cause of patient mortality in intensive care units (ICUs) worldwide. Considering that no causative treatment but only symptomatic care is available, it is obvious that there is a high unmet medical need for a new therapeutic concept. One reason for a missing etiologic therapy strategy is the multifactorial origin of ARDS, which leads to a large heterogeneity of patients. This review summarizes the various kinds of ARDS onset with a special focus on the role of reactive oxygen species (ROS), which are generally linked to ARDS development and progression. Taking a closer look at the data which already have been established in mouse models, this review finally proposes the translation of these results on successful antioxidant use in a personalized approach to the ICU patient as a potential adjuvant to standard ARDS treatment.