Arterial Blood Gas as a Predictor of Mortality in COVID Pneumonia Patients Initiated on Noninvasive Mechanical Ventilation: A Retrospective Analysis.
Indian J Crit Care Med
; 25(8): 866-871, 2021 Aug.
Article
in English
| MEDLINE | ID: covidwho-1355116
ABSTRACT
Background:
The alveolar-arterial oxygen (A-a) gradient measures the difference between the oxygen concentration in alveoli and the arterial system, which has considerable clinical utility. Materials andmethods:
It was a retrospective, observational cohort study involving the analysis of patients diagnosed with acute COVID pneumonia and required noninvasive mechanical ventilation (NIV) over a period of 3 months. The primary objective was to investigate the utility of the A-a gradient (pre-NIV) as a predictor of 28-day mortality in COVID pneumonia. The secondary objective included the utility of other arterial blood gas (ABG) parameters (pre-NIV) as a predictor of 28-day mortality. The outcome was also compared between survivors and nonsurvivors. The outcome variables were analyzed by receiver-operating characteristic (ROC) curve, Youden index, and regression analysis.Results:
The optimal criterion for A-a gradient to predict 28-day mortality was calculated as ≤430.43 at a Youden index of 0.5029, with the highest area under the curve (AUC) of 0.755 (p <0.0001). On regression analysis, the odds ratio for the A-a gradient was 0.99. A significant difference was observed in ABG predictors, including PaO2, PaCO2, A-a gradient, AO2, and arterial-alveolar (a-A) (%) among nonsurvivors vs survivors (p-value <0.001). The vasopressor requirement, need for renal replacement therapy, total parenteral requirement, and blood transfusion were higher among nonsurvivors; however, a significant difference was achieved with the vasopressor need (p <0.001).Conclusion:
This study demonstrated that the A-a gradient is a significant predictor of mortality in patients initiated on NIV for worsening respiratory distress in COVID pneumonia. All other ABG parameters also showed a significant AUC for predicting 28-day mortality, although with variable sensitivity and specificity. Key messages COVID-19 pneumonia shows an initial presentation with type 1 respiratory failure with increased A-a gradient, while a subsequent impending type 2 respiratory failure requires invasive ventilation. A significant difference was observed in ABG predictors, including PaO2, PaCO2, A-a gradient, AO2, and a-A (%) among nonsurvivors vs survivors. (p-value <0.001). The vasopressor requirement, need for renal replacement therapy, total parenteral requirement, and blood transfusion need were higher among nonsurvivors than survivors; however, a significant difference was achieved with the vasopressor need (p <0.001). How to cite this article Gupta B, Jain G, Chandrakar S, Gupta N, Agarwal A. Arterial Blood Gas as a Predictor of Mortality in COVID Pneumonia Patients Initiated on Noninvasive Mechanical Ventilation A Retrospective Analysis. Indian J Crit Care Med 2021;25(8)866-871.
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Type of study:
Cohort study
/
Diagnostic study
/
Observational study
/
Prognostic study
Topics:
Variants
Language:
English
Journal:
Indian J Crit Care Med
Year:
2021
Document Type:
Article
Affiliation country:
Jp-journals-10071-23917
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