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©The Author(s) 2025. Published by Baishideng Publishing Group Inc. All rights reserved.
Length of stay, duration of mechanical ventilation, mortality, and acute kidney injury in acute respiratory failure requiring endotracheal intubation
Panagiotis Papamichalis, Katerina G Oikonomou, Maria Xanthoudaki, Sophia K Papathanasiou, Antonios Papadogoulas, Apostolia Lemonia Skoura, Asimina Valsamaki, Dimitrios Plageras, Michail Papamichalis, Periklis Katsiafylloudis, Evangelia Papapostolou, Konstantinos Mantzarlis, Athanasios Koukoulis, Gkreta Mavrommati, Panagiotis Giannakos, Achilleas Chovas
Panagiotis Papamichalis, Katerina G Oikonomou, Maria Xanthoudaki, Antonios Papadogoulas, Periklis Katsiafylloudis, Evangelia Papapostolou, Achilleas Chovas, Intensive Care Unit, General Hospital of Larissa, Larissa 41221, Thessaly, Greece
Sophia K Papathanasiou, Dimitrios Plageras, Gkreta Mavrommati, Department of Internal Medicine, General Hospital of Larissa, Larissa 41221, Thessaly, Greece
Apostolia Lemonia Skoura, Department of Transfusion Medicine, University Hospital of Larissa, Larissa 41110, Thessaly, Greece
Asimina Valsamaki, Konstantinos Mantzarlis, Department of Critical Care, University Hospital of Larissa, Larissa 41110, Thessaly, Greece
Michail Papamichalis, Department of Cardiology, University Hospital of Larissa, Larissa 41110, Thessaly, Greece
Athanasios Koukoulis, Faculty of Medicine, University of Thessaly, Larissa 41500, Thessaly, Greece
Panagiotis Giannakos, Department of Cardiology, General Hospital of Larissa, Larissa 41221, Thessaly, Greece
Author contributions: Papamichalis P, Oikonomou KG, Xanthoudaki M, and Papathanasiou SK designed the article; Papadogoulas A, Valsamaki A, Skoura AL, Katsiafylloudis P, Papapostolou E, Plageras D, Koukoulis A, Mavrommati G, Giannakos P, and Mantzarlis K assisted in data gathering; Papamichalis P, Oikonomou KG, Xanthoudaki M, and Papathanasiou SK wrote the final version of the manuscript; Oikonomou KG performed English editing; Chovas A critically reviewed the paper; all authors approved the final version to publish.
Institutional review board statement: The study was approved by the institutional review board of General Hospital of Larissa, No. 4851.
Informed consent statement: Due to the retrospective nature of the study and in accordance with the Institutional review board statement, informed consent statement was waived.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
STROBE statement: The authors have read the STROBE Statement-checklist of items, and the manuscript was prepared and revised according to the STROBE Statement-checklist of items.
Data sharing statement: Data that support the findings of this study will be available upon request at the e-mail address of the corresponding author for research purposes.
Open Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
https://creativecommons.org/Licenses/by-nc/4.0/ Corresponding author: Panagiotis Papamichalis, MD, PhD, Intensive Care Unit, General Hospital of Larissa, 1 Tsakalof, Larissa 41221, Thessaly, Greece.
ppapamih@med.uth.gr
Received: November 29, 2024
Revised: April 28, 2025
Accepted: July 7, 2025
Published online: December 9, 2025
Processing time: 365 Days and 5.2 Hours
BACKGROUND
Critically ill patients often present on admission or develop acute respiratory failure requiring intubation and application of positive pressure ventilation during their hospital stay.
AIM
To investigate and identify the epidemiological data, parameters associated with respiratory settings or the mechanics, and values related to arterial blood gases (ABGs) that are associated with outcomes in critically ill patients.
METHODS
A retrospective analysis of 131 patients [mean age, 67.3 years; mean acute physiology and chronic health evaluation (APACHE) score, 21.4] with acute respiratory failure requiring invasive mechanical ventilation was performed. The parameters that were statistically analyzed included demographic data, the presence of comorbidities, the presence of coronavirus disease 19 (COVID-19), the respiratory rate (RR), peak airway pressure (Ppeak), minute ventilation (MV), positive end-expiratory pressure, and the values related to ABGs. In order to facilitate the statistical analysis, patients were evaluated and compared in groups: Survivors (n = 41) vs non-survivors (n = 90) and patients without acute kidney injury (AKI) (n = 60) vs patients with AKI (n = 71). Four endpoints were studied: Mortality, length of stay, duration of mechanical ventilation, and AKI. Group comparisons were performed using the following statistical tests: The χ2 test with Yates’ correction, Fisher’s exact test, the Mann-Whitney U test, and Spearman’s rank correlation analysis. Binary logistic regression analysis conducted after the univariate statistical tests facilitated the investigation of the independent predictors of mortality and AKI. A two-sided P value of less than 0.05 was considered the threshold of statistical significance.
RESULTS
Non-survivors presented statistically significant differences in terms of being older in age, the presence of comorbidities, elevated APACHE score, medical (vs surgical) reasons for admission, presence of COVID-19, lower pH at ABGs, lower values of the oxygenation ratio (arterial oxygen partial pressure to the fraction of inspired oxygen) and arterial oxygen partial pressure, and elevated values of Ppeak, positive end-expiratory pressure, RR, arterial carbon dioxide partial pressure, and MV. The factors identified as independent predictors of mortality were the presence of comorbidities, APACHE score, COVID-19 status, arterial carbon dioxide partial pressure, Ppeak, RR, and MV. COVID-19 presence and elevated values of RR and Ppeak were positively correlated with the other three endpoints (length of stay, the duration of mechanical ventilation in survivors, and the occurrence of AKI in the entire study population) that were studied. The other parameters exhibited a variable (either positive/negative, or no) correlation to the four endpoints under investigation.
CONCLUSION
Among all investigated outcome measures, COVID-19, Ppeak, and RR were strongly associated with all the endpoints studied, suggesting that proper interventions involving the modifiable respiratory parameters Ppeak and RR could improve the overall outcome in these patients. A novel finding of this study was the relationship between RR and AKI, which is worthy of further investigation. Future studies may explore the clinical interpretation of these findings to improve outcomes in critically ill patients with acute respiratory failure.
Core Tip: Identifying prognostic factors in patients with acute respiratory failure requiring invasive mechanical/positive pressure ventilation remains a challenge to date. In the present study, the relationships of the epidemiological, respiratory, and arterial blood gas parameters to the four outcome measures of mortality, development of acute kidney injury, length of stay, and the duration of mechanical ventilation were evaluated. It was revealed that epidemiological factors such as the coronavirus disease 2019 presence and the respiratory parameters peak airway pressure and respiratory rate (RR) affected all the studied outcome measures. The possibility of improving outcomes by reducing the peak airway pressure and the RR and the observed association between RR and acute kidney injury needs further evaluation in future studies.
