Blood oxygenation state in COVID-19 patients: Unexplored role of 2,3-bisphosphoglycerate

Maria Sofia Bertilacchi; Rebecca Piccarducci; Alessandro Celi; Lorenzo Germelli; Chiara Romei; Brian Bartholmai; Greta Barbieri; Chiara Giacomelli; Claudia Martini

doi:10.1016/j.bj.2024.100723

Blood oxygenation state in COVID-19 patients: Unexplored role of 2,3-bisphosphoglycerate

Biomed J. 2024 Apr 5:100723. doi: 10.1016/j.bj.2024.100723. Online ahead of print.

Authors

Maria Sofia Bertilacchi¹, Rebecca Piccarducci¹, Alessandro Celi², Lorenzo Germelli¹, Chiara Romei³, Brian Bartholmai⁴, Greta Barbieri⁵, Chiara Giacomelli⁶, Claudia Martini¹

Affiliations

¹ Department of Pharmacy, University of Pisa, 56126, Pisa, Italy.
² Department of Surgical, Medical and Molecular Pathology and Critical Care, University of Pisa, Pisa, 56126, Italy.
³ Department of Radiology, Pisa University Hospital, Pisa, Italy. Electronic address: chiara.romei@gmail.com.
⁴ Division of Radiology, Mayo Clinic Rochester, Rochester, MN, USA.
⁵ Department of Emergency Medicine Department, Pisa University Hospital, Italy.
⁶ Department of Pharmacy, University of Pisa, 56126, Pisa, Italy. Electronic address: chiara.giacomelli@unipi.it.

PMID: 38583585
DOI: 10.1016/j.bj.2024.100723

Abstract

Background: COVID-19 reduces lung functionality causing a decrease of blood oxygen levels (hypoxemia) often related to a decreased cellular oxygenation (hypoxia). Besides lung injury, other factors are implicated in the regulation of oxygen availability such as pH, partial arterial carbon dioxide tension (PaCO₂), temperature, and erythrocytic 2,3-bisphosphoglycerate (2,3-BPG) levels, all factors affecting hemoglobin saturation curve. However, few data are currently available regarding the 2,3-BPG modulation in SARS-CoV-2 affected patients at the hospital admission.

Material and methods: Sixty-eight COVID-19 patients were enrolled at hospital admission. The lung involvement was quantified using chest-Computer Tomography (CT) analysed with automatic software (CALIPER). Haemoglobin concentrations, glycemia, and routine analysis were evaluated in the whole blood, while partial arterial oxygen tension (PaO₂), PaCO₂, pH, and HCO₃^- were assessed by arterial blood gas analysis. 2,3-BPG levels were assessed by specific immunoenzymatic assays in RBCs.

Results: A higher percentage of interstitial lung disease (ILD) and vascular pulmonary-related structure (VRS) volume on chest-CT quantified with CALIPER had been found in COVID-19 patients with a worse disease outcome (R = 0.4342; and R = 0.3641, respectively). Furthermore, patients with lower PaO₂ showed an imbalanced acid-base equilibrium (pH, p = 0.0208; PaCO₂, p = 0.0496) and a higher 2,3-BPG levels (p = 0.0221). The 2,3-BPG levels were also lower in patients with metabolic alkalosis (p = 0.0012 vs. no alkalosis; and p = 0.0383 vs. respiratory alkalosis).

Conclusions: Overall, the data reveal a different pattern of activation of blood oxygenation compensatory mechanisms reflecting a different course of the COVID-19 disease specifically focusing on 2,3-BPG modulation.

Keywords: 2,3- bisphosphoglycerate; Arterial blood gas (ABG); Blood oxygenation; COVID-19; Chest computed tomography.