Influence of Chronotypes in Respiratory Pathology.

The circadian rhythm of sleep occurs in a cyclical 24-h pattern that is adjusted by the influence of several main synchronizers or "zeitgebers". The most powerful synchronizer is the light-dark alternation, but also, socio-economic factors play a role, such as social and work relationships. Circadian rhythm regulation plays a crucial role in human health. This disruption of circadian rhythm can lead to increased incidence of diseases: diabetes, obesity, cancer, neurodegenerative diseases, increased risk of cardiovascular disease and stroke. Polygenic variations and environmental factors influence the circadian rhythm of each person. This is known as chronotype, which manifests itself as the degree of morning of evening preferences of each individual. There are indications to establish an association between individual chronotype preferences and the behavior of respiratory diseases.

El ritmo circadiano del sueño ocurre en un patrón cíclico de 24 horas que se ajusta por la influencia de varios sincronizadores principales o zeitgebers. El sincronizador más poderoso es la alternancia luz-oscuridad, además de los factores socioeconómicos, las relaciones sociales y las laborales. La regulación del ritmo circadiano juega un papel crucial en la salud humana. Esta interrupción del ritmo circadiano puede conducir a una mayor incidencia de enfermedades: diabetes, obesidad, cáncer, enfermedades neurodegenerativas, mayor riesgo de enfermedad cardiovascular e ictus.Las variaciones poligénicas y los factores ambientales influyen en el ritmo circadiano de cada persona. Esto se conoce como cronotipo, que se manifiesta como el grado de preferencias matutinas o vespertinas de cada individuo. Existen indicios para establecer una asociación entre las preferencias individuales de cronotipo y el comportamiento de las enfermedades respiratorias.

High-flow nasal cannula for Acute Respiratory Distress Syndrome (ARDS) due to COVID-19.

INTRODUCTION: High-flow nasal cannula oxygen therapy (HFNC) has been shown to be a useful therapy in the treatment of patients with Acute Respiratory Distress Syndrome (ARDS), but its efficacy is still unknown in patients with COVID-19. Our objective is to describe its utility as therapy for the treatment of ARDS caused by SARS-CoV-2. METHODS: A retrospective, observational study was performed at a single centre, evaluating patients with ARDS secondary to COVID-19 treated with HFNC. The main outcome was the intubation rate at day 30, which defined failure of therapy. We also analysed the role of the ROX index to predict the need for intubation. RESULTS: In the study period, 196 patients with bilateral pneumonia were admitted to our pulmonology unit, 40 of whom were treated with HFNC due to the presence of ARDS. The intubation rate at day 30 was 52.5%, and overall mortality was 22.5%. After initiating HFNC, the SpO2/FiO2 ratio was significantly better in the group that did not require intubation (113.4±6.6 vs 93.7±6.7, p=0.020), as was the ROX index (5.0±1.6 vs 4.0±1.0, p=0.018). A ROX index less than 4.94 measured 2 to 6 h after the start of therapy was associated with increased risk of intubation (HR 4.03 [95% CI 1.18 - 13.7]; p=0.026). CONCLUSION: High-flow therapy is a useful treatment in ARDS in order to avoid intubation or as a bridge therapy, and no increased mortality was observed secondary to the delay in intubation. After initiating HFNC, a ROX index below 4.94 predicts the need for intubation.