Stroke-associated pneumonia with low PaO₂/FiO₂ ratio in acute large vessel occlusion after endovascular therapy : risk factors and prognosis

Abstract

Background: Stroke-associated pneumonia (SAP) often occurs after ischemic stroke. A deterioration in SAP manifests itself in a decreased partial pressure oxygen (PaO2)/fraction of inspired oxygen (FiO2) ratio, indicating gas exchange dysfunction. We aimed to investigate independent predictors and outcomes of SAP with low PaO2/FiO2 ratio among patients with acute large vessel occlusion (ALVO) undergoing endovascular therapy. Methods: We retrospectively analyzed the prospective data of consecutive adult post-interventional patients with ALVO admitted to neuro-intensive care units in Wuhan No. 1 Hospital from December 2020 to December 2022. Patients developing SAP without coronavirus disease 2019 were included in this study and divided into two subgroups: PaO2/FiO2 ratio > 240 and ≤ 240. The primary outcome was favorable neuro-function at 90 days (modified Rankin Scale score of 0–2). Secondary outcomes included hospitalization days, occurrence of symptomatic intracerebral hemorrhage, and 90-day mortality. The independent risk factors and prognosis for SAP with PaO2/FiO2 ratio ≤ 240 were identified by logistic regression analyses. Results: A total of 159 subjects developing SAP were included in this study: 53 with PaO2/FiO2 ratio > 240 and 106 with ratio ≤ 240. Compared to subjects with PaO2/FiO2 ratio > 240, those with PaO2/FiO2 ratio ≤ 240 had older ages, higher baseline National Institutes of Health Stroke Scales scores, larger proportions of baseline Glasgow Coma Scale (GCS) score of 3–8 and grade of kobuta water swallow test ≥ 3, higher white blood cell (WBC) counts (all p values <0.05). The independent predictors for SAP with PaO2/FiO2 ratio ≤ 240 included ages (adjusted odds ratio [OR], 1.043; 95% confidential interval [CI], 1.011–1.077; p = 0.009), baseline GCS scores of 3–8 (adjusted OR, 2.802; 95% CI, 1.214–6.465; p = 0.016), and ln-transformed WBC counts after SAP diagnosis (adjusted OR, 3.977; 95% CI, 1.226–12.896; p = 0.021). SAP with PaO2/FiO2 ratio ≤ 240 was robustly associated with longer hospitalization days (adjusted OR, 1.074; 95% CI, 1.01–1.143; p = 0.024). Conclusion: SAP with PaO2/FiO2 ratio ≤ 240 is shown in significant relevance to the prolonged in-hospital stays among post-interventional patients. Older ages, baseline GCS scores of 3–8, and higher WBC counts after SAP diagnosis can independently predict the occurrence of SAP with a lower PaO2/FiO2 ratio. Further validation studies are needed.