Outcomes of patients with hypoxic respiratory failure due to Coronavirus 19 and a normal chest radiograph on admission based on initial D-Dimer level

Introduction:Despite rapidly emerging data on all possible manifestations and complications of Coronavirus 19 (COVID19) disease, little evidence is available on patients presenting with acute hypoxic respiratory failure and a normal chest radiograph (CXR). The goal of our study was to evaluate outcomes of patients with normal CXR on admission and hypoxic respiratory failure due to COVID19 infection accordingly to their D-Dimer level on admission. Methods:We conducted a retrospective review of all adult patients with confirmed COVID19 infection presenting with acute hypoxic respiratory failure requiring supplemental oxygen and a normal CXR on admission, admitted to Bronx Care Health System between March and June 2020. A total of 115 patients were included and classified into 2 groups accordingly to their initial D-Dimer level: D-dimer level ≥ 4 times upper limit of normal (ULN) and a D-Dimer level ≤ 4 times ULN. Primary outcome was mortality and secondary outcomes were hospital length of stay (HLOS), need for mechanical ventilation, shock, acute kidney injury (AKI), electrolyte abnormalities. Results:115 patients were included and classified according to the initial D-Dimer level. 31 patients had a d-dimer level ≥ 4 times ULN and 84 had d-dimers ≤ 4 times ULN. Patients with d-dimer level ≥ 4 times ULN were older (mean age 65 vs 55 p<0.05, CI 3.4-16.7) and more likely to be African-American in comparison to any other race (58% vs 28.5%, p<0.05). Patients with initial normal CXR and a d-dimer level ≥ 4 times ULN had significantly higher mortality, higher requirement for mechanical ventilation, higher serum lactic dehydrogenase (LDH) and were more likely to have acute kidney injury (AKI) compared with patients with lower levels of ddimers. We found no differences in hospital or intensive care length of stay (LOS) among the groups. Conclusions:Patients with hypoxic respiratory failure with elevated d-dimers and normal admission CXR have higher mortality, more likely develop shock, renal failure and need for mechanical ventilation. Care must be taken in both triage and discharge planning in those patients, as they need close monitoring. This is especially important in African-American patients and those with increased serum LDH levels. A composite scoring system for this group of patients will be helpful.