Predictors of Success and Impact on Morbidity and Mortality of Noninvasive Ventilation in Critically Ill COVID-19 Patients in Morocco: A Monocentric Cohort Study

Abstract

Abstract Background: SARS-CoV-2 pneumonia can progress to acute respiratory failure and multiple organ dysfunction syndrome. This infection has evolved into a global pandemic. Several oxygenation support methods have been used, such as high flow nasal oxygen therapy (HFNO) and non-invasive ventilation (NIV). The indications and effects of NIV support have been debated in the literature, with varying results across heterogeneous populations. Objective: The aim of this study is to investigate the impact of NIV on mortality and morbidity in ICU COVID-19 patients, in order to identify the predictive factors of NIV success.Materials and Methods: This study was performed in the intensive care units at the Duc de Tovar Hospital and at the Mohammed VI Hospital of Tangier, from August 2020 to October 2021. We retrospectively included 256 patients aged over 16 years who received NIV for a minimum duration of 6 hours. Results: Out of 842 patients admitted to the intensive care unit, 256 of whom were eligible according to our inclusion criteria. The median age was 61 years old [51.25–68.75], with a male predominance. Hypertension, diabetes, and obesity were the most frequent comorbidities in our series. Regarding the respiratory status of our patients at admission, the median respiratory rate was 35 breaths/minute, the median oxygen saturation was 75%, and 26.2% of patients showed signs of respiratory distress. The biological abnormalities observed included elevated inflammatory and coagulation markers and lymphopenia, with a neutrophil-to-lymphocyte ratio (NLR) on admission greater than 10.5 in half of the patients. The median lung injury extension on chest CT at admission was 75%, and 59% of patients had more than 75% lung involvement. Concerning NIV, the median time to initiation from symptom onset was 11 days, and from ICU admission was 2 days. NIV was initiated at ICU admission in 17.2% of patients, after worsening on non-rebreather mask in 44.1%, and after High Flow Nasal Oxygen (HFNO) failure in 38.7%. The median PaO 2 /FiO 2 ratio before starting NIV was 64. Patient positioning was allocated according to respiratory status at admission and response to NIV: prone position more than 18 hours/day in 5.1%, lateral decubitus in 31.3%, and supine position in 56.3%. The median duration of NIV application was 2 days [1–5]. The main complications observed were ARDS in 62.9% of patients, cytokine storm syndrome in 26.9%, and renal failure in 18.8%. In addition, 11 patients developed ventilator-associated pneumonia, 3 patients developed subcutaneous emphysema, 1 patient presented with pneumothorax, and 4 patients presented with pneumomediastinum under NIV. Our study showed that several predictors of NIV failure were related to the severity of pulmonary and systemic involvement, including ARDS, pulmonary embolism, and length of hospital stay. Younger age, on the other hand, was associated with NIV success. The high mortality rate of 91% found in our series reflects the severity of illness in patients who received NIV. The critical condition of these patients is explained by the hypoxia at admission, the extent of advanced lung injury and organ failure reflected by the morbidity reported in our series, as well as the delay in ICU admission and consequently in the initiation of NIV, associated with elevated biological markers reflecting the degree of systemic inflammation. Conclusion: NIV can be used in COVID-19 patients with respiratory distress after the failure of other oxygenation methods. However, several predictors of failure were identified, including ARDS, pulmonary embolism, and length of hospital stay, while younger age was associated with greater success. These severity factors require close clinical monitoring and continuous oxygenation assessment, given the high risk of NIV failure.