Ventilatory strategies and supportive care in acute respiratory distress syndrome

Nanomedicines Targeting Respiratory Injuries for Pulmonary Disease Management

The respiratory system holds crucial importance in the biology of vertebrate animals. Injuries of the respiratory system caused by viral infections (e.g., by COVID‐19, MERS, and SARS) can lead to severe or lethal conditions. So far there are no effective treatments for respiratory injuries. This represents a highly unmet clinical need, e.g., during the current COVID‐19 pandemic. Nanomedicines have high potential in the treatment of respiratory injuries. In this review, the pathology and clinical treatments of major respiratory injuries, acute lung injury, and acute respiratory distress syndrome are briefly summarized. The review primarily focuses on nanomedicines based on liposomes, solid lipid nanoparticles, polymeric nanoparticles, and inorganic nanoparticles, which are tested in preclinical models for the treatment of respiratory injuries. These nanomedicines are utilized to deliver a variety of therapeutic agents, including corticosteroids, statins, and nucleic acids. Furthermore, nanomedicines are also investigated for other respiratory diseases including chronic obstructive pulmonary disease and asthma. The promising preclinical results of various nanoformulations from these studies suggest the potential of nanomedicines for future clinical management of respiratory viral infections and diseases.

Otolaryngology during COVID-19: Preventive care and precautionary measures

Since the outbreak of novel coronavirus disease (COVID-19) in December 2019, it has spread to various regions and countries, forming a global pandemic. Reducing nosocomial infection is a new issue and challenge for all healthcare systems. Otolaryngology is a high-risk specialty as it close contact with upper respiratory tract mucous, secretions, droplets and aerosols during procedures and surgery. Therefore, infection prevention and control measures for this specialty are essential. Literatures on the epidemiology, clinical characteristics and infection control measures of COVID-19 were reviewed, practical knowledge from first-line otolaryngologists in China, the United States, and Brazil were reviewed and collated. It was recommended that otolaryngology professionals should improve screening in suspected patients with relevant nasal and pharyngeal symptoms and signs, suspend non-emergency consultations and examinations in clinics, and rearrange the working procedures in operating rooms. The guidelines of personal protective equipment for swab sampling, endoscopy and surgery were listed. Indications for tracheotomy during the pandemic should be carefully considered to avoid unnecessary airway opening and aerosol-generation; precautions during surgery to reduce the risk of exposure and infection were illustrated. This review aimed to provide recommendations for otolaryngologists to enhance personal protection against COVID-19 and reduce the risk of nosocomial infection.

The Impact of the Interferon/TNF-Related Apoptosis-Inducing Ligand Signaling Axis on Disease Progression in Respiratory Viral Infection and Beyond

Interferons (IFNs) are well described to be rapidly induced upon pathogen-associated pattern recognition. After binding to their respective IFN receptors and activation of the cellular JAK/signal transducer and activator of transcription signaling cascade, they stimulate the transcription of a plethora of IFN-stimulated genes (ISGs) in infected as well as bystander cells such as the non-infected epithelium and cells of the immune system. ISGs may directly act on the invading pathogen or can either positively or negatively regulate the innate and adaptive immune response. However, IFNs and ISGs do not only play a key role in the limitation of pathogen spread but have also been recently found to provoke an unbalanced, overshooting inflammatory response causing tissue injury and hampering repair processes. A prominent regulator of disease outcome, especially in-but not limited to-respiratory viral infection, is the IFN-dependent mediator TRAIL (TNF-related apoptosis-inducing ligand) produced by several cell types including immune cells such as macrophages or T cells. First described as an apoptosis-inducing agent in transformed cells, it is now also well established to rapidly evoke cellular stress pathways in epithelial cells, finally leading to caspase-dependent or -independent cell death. Hereby, pathogen spread is limited; however in some cases, also the surrounding tissue is severely harmed, thus augmenting disease severity. Interestingly, the lack of a strictly controlled and well balanced IFN/TRAIL signaling response has not only been implicated in viral infection but might furthermore be an important determinant of disease progression in bacterial superinfections and in chronic respiratory illness. Conclusively, the IFN/TRAIL signaling axis is subjected to a complex modulation and might be exploited for the evaluation of new therapeutic concepts aiming at attenuation of tissue injury.

Ventilatory strategies and supportive care in acute respiratory distress syndrome

While antiviral therapy is an important component of care in patients with the acute respiratory distress syndrome (ARDS) following influenza infection, it is not sufficient to ensure good outcomes, and additional measures are usually necessary. Patients usually receive high levels of supplemental oxygen to counteract the hypoxemia resulting from severe gas exchange abnormalities. Many patients also receive invasive mechanical ventilation for support for oxygenation, while in resource-poor settings, supplemental oxygen via face mask may be the only available intervention. Patients with ARDS receiving mechanical ventilation should receive lung-protective ventilation, whereby tidal volume is decreased to 6 ml/kg of their predicted weight and distending pressures are maintained ≤ 30 cm H2 O, as well as increased inspired oxygen concentrations and positive end-expiratory pressure (PEEP) to prevent atelectasis and support oxygenation. While these measures are sufficient in most patients, a minority develop refractory hypoxemia and may receive additional therapies, including prone positioning, inhaled vasodilators, extracorporeal membrane oxygenation, recruitment maneuvers followed by high PEEP, and neuromuscular blockade, although recent data suggest that this last option may be warranted earlier in the clinical course before development of refractory hypoxemia. Application of these "rescue strategies" is complicated by the lack of guidance in the literature regarding implementation. While much attention is devoted to these strategies, clinicians must not lose sight of simple interventions that affect patient outcomes including head of bed elevation, prophylaxis against venous thromboembolism and gastrointestinal bleeding, judicious use of fluids in the post-resuscitative phase, and a protocol-based approach to sedation and spontaneous breathing trials.