Estimating the Case Fatality Risk of COVID-19 among Mechanically Ventilated Patients

Clinical characteristics associated with mortality of COVID-19 patients admitted to an intensive care unit of a tertiary hospital in South Africa

BACKGROUND

Over 130 million people have been diagnosed with Coronavirus disease 2019 (COVID-19), and more than one million fatalities have been reported worldwide. South Africa is unique in having a quadruple disease burden of type 2 diabetes, hypertension, human immunodeficiency virus (HIV) and tuberculosis, making COVID-19-related mortality of particular interest in the country. The aim of this study was to investigate the clinical characteristics and associated mortality of COVID-19 patients admitted to an intensive care unit (ICU) in a South African setting.

METHODS AND FINDINGS

We performed a prospective observational study of patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection admitted to the ICU of a South African tertiary hospital in Cape Town. The mortality and discharge rates were the primary outcomes. Demographic, clinical and laboratory data were analysed, and multivariable robust Poisson regression model was used to identify risk factors for mortality. Furthermore, Cox proportional hazards regression model was performed to assess the association between time to death and the predictor variables. Factors associated with death (time to death) at p-value < 0.05 were considered statistically significant. Of the 402 patients admitted to the ICU, 250 (62%) died, and another 12 (3%) died in the hospital after being discharged from the ICU. The median age of the study population was 54.1 years (IQR: 46.0-61.6). The mortality rate among those who were intubated was significantly higher at 201/221 (91%). After adjusting for confounding, multivariable robust Poisson regression analysis revealed that age more than 48 years, requiring invasive mechanical ventilation, HIV status, procalcitonin (PCT), Troponin T, Aspartate Aminotransferase (AST), and a low pH on admission all significantly predicted mortality. Three main risk factors predictive of mortality were identified in the analysis using Cox regression Cox proportional hazards regression model. HIV positive status, myalgia, and intubated in the ICU were identified as independent prognostic factors.

CONCLUSIONS

In this study, the mortality rate in COVID-19 patients admitted to the ICU was high. Older age, the need for invasive mechanical ventilation, HIV status, and metabolic acidosis were found to be significant predictors of mortality in patients admitted to the ICU.

Care of the Seriously Ill Patient with SARS-CoV-2

In late 2019, SARS-CoV-2 caused the greatest global health crisis in a century, impacting all aspects of society. As the COVID-19 pandemic evolved throughout 2020 and 2021, multiple variants emerged, contributing to multiple surges in cases of COVID-19 worldwide. In 2021, highly effective vaccines became available, although the pandemic continues into 2022. There has been tremendous expansion of basic, translational, and clinical knowledge about SARS-CoV-2 and COVID-19 since the pandemic's onset. Treatment options have been rapidly explored, attempting to repurpose preexisting medications in tandem with development and evaluation of novel agents. Care of the seriously ill patient is examined.

Prone positioning for mechanically ventilated patients with coronavirus disease 2019: the experience of an Irish regional hospital intensive care unit

Background

The benefits of prone positioning in acute respiratory distress syndrome (ARDS) have been known for many years. While some controversy exists regarding whether coronavirus disease 2019 (COVID-19) pneumonia should be treated with the same therapeutic strategies as for non-COVID ARDS, the Surviving Sepsis Campaign still provide a weak recommendation to utilise prone positioning in this setting.

Aims

The aims of this study are to ascertain if prone positioning improves oxygenation significantly in mechanically ventilated patients with severe COVID-19 ARDS and to describe the feasibility of frequent prone positioning in an Irish regional hospital intensive care unit (ICU) with limited prior experience.

Methods

In this retrospective, observational cohort study, we investigate if the PaO₂/FiO₂ ratio and ventilatory ratio improve during and following prone positioning, and whether this improvement correlates with patient baseline characteristics or survival.

Results

Between March 2020 and 2021, 12 patients underwent prone positioning while mechanically ventilated for severe COVID ARDS. Sixty-six percent were male, mean age 60.9 (± 10.5), mean BMI 33.5 (± 6.74) and median APACHE II score on admission to ICU was 10.5 (7.25–16.3). Further, 83% were proned within 24 h of being intubated due to refractory hypoxaemia. PaO₂/FiO₂ ratio improved from 11.6 kPa (9.80–13.8) to 15.80 kPa (13.1–19.6) while prone, p < 0.0001.

Conclusions

We found prone positioning to be a safe method of significantly improving oxygenation in mechanically ventilated patients with severe COVID-19 ARDS. We did not find a relationship between patient baseline characteristics nor illness severity and degree of PaO₂/FiO₂ ratio improvement, nor did we find a relationship between degree of PaO₂/FiO₂ ratio improvement and survival.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11845-022-03085-9.