Oxygenated Hemoglobin: An Indicator of Severe Community-Acquired Pneumonia in Chronic Obstructive Pulmonary Disease Patients

Abstract

<bold>Introduction :</bold> Recent studies have indicated that oxygenated hemoglobin (OxyHem) is a valuable prognostic indicator in acute exacerbations of Chronic Obstructive Pulmonary Disease (COPD). We aimed to evaluate the predictive value of OxyHem in patients hospitalized for severe community-acquired pneumonia (CAP). <bold>Methods:</bold> We conducted a cross-sectional study at our Pulmonology department from January 2022 to December 2023. Patients with confirmed COPD and a history of CAP hospitalization were assessed for disease severity using the GOLD 2023 guidelines. OxyHem (Hb × SpO2) was calculated. Patients were divided into two groups: those transferred to the ICU or deceased (G1), and those not transferred to the ICU (G2). <bold>Results:</bold> We enrolled 214 patients with a mean age of 62.65 ± 9.10 years and a sex ratio of 2.5. Overall, 118 patients (55%) required transfer to the ICU, and 21 (9.8%) died during the study period. Non-survivors were predominantly classified as Group E. No significant difference was observed in PaO2 levels between the two groups. However, OxyHem was significantly lower in G1 compared to G2 (8.14 ± 2.42 vs. 10.51 ± 1.47 g/dL, P ≤ 10⁻³). Several factors independently predicted ICU transfer, including BMI, CRP levels, lymphocyte count, acute kidney injury, high lactate dehydrogenase levels, and oxyHem. Notably, the predictive value of oxyHem (p < 10^-3) surpassed that of Hb, SpO2, or oxygen flow rate. Remarkably, oxyHem showed a predictive power at a cutoff value of 9.28 g/dL, with a sensitivity of 89% and a specificity of 88%. <bold>Conclusion:</bold> This study underscores the value of oxyHem as a practical marker for predicting poor outcomes in COPD patients with CAP.