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

Kun Tang¹Jia Li¹Yucheng Wang¹Zhangbao Guo¹Yun Yang¹Fangliang Guo¹Yin Cai²Wenhua Liu^1*

• ¹Department of Neurology, Wuhan No. 1 Hospital, Wuhan, China
• ²Hong Kong Polytechnic University, Kowloon, Hong Kong, SAR China

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). Conclusions: 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.