Identifying the predictors of noninvasive ventilation (NIV) failure has attracted significant interest because of the strong link between failure and poor outcomes. However, very little attention has been paid to the timing of the failure. This narrative review focuses on the causes of NIV failure and risk factors and potential remedies for NIV failure, based on the timing factor.

Introduction Severe exacerbations are the leading cause of fatal events in chronic obstructive pulmonary disease (COPD). The new Global Initiative for Chronic Obstructive Lung Disease strategy included the number of exacerbations in the grading of the disease. The primary aim of this study was to evaluate the potentially modifiable precipitating factors of frequent severe exacerbations requiring hospital admission in COPD. The secondary aim was to investigate the risk factors of readmission within 2 months following an exacerbation requiring hospitalisation. Methods Data regarding the number of exacerbations in the previous year, current comorbidities, medications, and clinical and functional status of COPD patients were evaluated. Results We included 107 COPD patients (85% men). The mean number of severe exacerbations was 1.3 ± 1.7 (per patient/per year), and 37.4% of the patients had frequent severe exacerbations (≥ 2/year). Multivariate analysis indicated that haematocrit < 41%, angiotensin converting enzyme inhibitor or angiotensin receptor blocker use, positive gastro-oesophageal reflux disease symptoms, poor adherence to inhaled therapy/regular outpatient follow-up visits and FEV₁ < 50% were independent predictors of frequent severe exacerbations. Readmission rate within 2 months after hospital discharge was 39.3%. The independent risk factors of readmission were poor adherence to inhaled therapy/regular outpatient follow-up visits, serum haematocrit < 41%, and FEV₁ < 50%. Conclusion Chronic obstructive pulmonary disease patients with frequent exacerbations should be carefully assessed for modifiable confounding risk factors regardless of poor lung function to decrease exacerbation frequency and related poor prognosis.

There are limited data on the long-term outcomes of COVID-19 from different parts of the world. To determine risk factors of 90-day mortality in critically ill patients in Turkish intensive care units (ICUs), with respiratory failure. Retrospective, observational cohort. Patients with laboratory-confirmed COVID-19 and who had been followed up in the ICUs with respiratory failure for more than 24 hours were included in the study. Their demographics, clinical characteristics, laboratory variables, treatment protocols, and survival data were recorded. A total of 421 patients were included. The median age was 67 (IQR: 57-76) years, and 251 patients (59.6%) were men. The 90-day mortality rate was 55.1%. The factors independently associated with 90-day mortality were invasive mechanical ventilation (IMV) (HR 4.09 [95% CI: [2.20-7.63], P < .001), lactate level >2 mmol/L (2.78 [1.93-4.01], P < .001), age ≥60 years (2.45 [1.48-4.06)], P < .001), cardiac arrhythmia during ICU stay (2.01 [1.27-3.20], P = .003), vasopressor treatment (1.94 [1.32-2.84], P = .001), positive fluid balance of ≥600 mL/day (1.68 [1.21-2.34], P = .002), PaO₂/FiO₂ ratio of ≤150 mmHg (1.66 [1.18-2.32], P = .003), and ECOG score ≥1 (1.42 [1.00-2.02], P = .050). Long-term mortality was high in critically ill patients with COVID-19 hospitalized in intensive care units in Turkey. Invasive mechanical ventilation, lactate level, age, cardiac arrhythmia, vasopressor therapy, positive fluid balance, severe hypoxemia and ECOG score were the independent risk factors for 90-day mortality.