The predictive value of PaO(2)/FIO(2) and additional parameters for in-hospital mortality in patients with acute pulmonary embolism: an 8-year prospective observational single-center cohort study

BACKGROUND: Rapid stratification and appropriate treatment on admission are critical to saving lives of patients with acute pulmonary embolism (PE). None of the clinical prediction tools perform well when applied to all patients with acute PE. It may be important to integrate respiratory features into the 2014 European Society of Cardiology model. First, we aimed to assess the relationship between the arterial partial pressure of oxygen/fraction of inspired oxygen (PaO(2)/FIO(2)) ratio and in-hospital mortality, determine the optimal cutoff value of PaO(2)/FIO(2), and determine if this value, which is quick and easy to obtain on admission, is a predictor of in-hospital mortality in this population. Second, we aimed to evaluate the potential additional determinants including laboratory parameters that may affect the in-hospital mortality. We hypothesized that the PaO2/FiO2 ratio would be a clinical prediction tool for in-hospital mortality in patients with acute PE. METHODS: A prospective single-center observational cohort study was conducted in Beijing Hospital from January 2010 to November 2017. Arterial blood gas analysis data captured on admission, clinical characteristics, risk factors, laboratory data, imaging findings, and in-hospital mortality were compared between survivors and non-survivors. The area under the receiver operating characteristic curve (AUC) for in-hospital mortality based on the PaO(2)/FiO(2) value was determined, and the association between the parameters and in-hospital mortality was analyzed by using logistic regression analysis. RESULTS: Body mass index, history of cancer, PaO(2)/FiO(2) value, pulse rate, cardiac troponin I level, lactate dehydrogenase level, white blood cell count, D-dimer level, and risk stratification measurements differed between survivors and non-survivors. The optimal cutoff value of PaO(2)/FiO(2) for predicting mortality was 265 (AUC = 0.765, P < 0.001). Only a PaO(2)/FiO(2) ratio < 265 (95% confidence interval [CI] 1.823–21.483, P = 0.004), history of cancer (95% CI 1.161–15.927, P = 0.029), and risk stratification (95% CI 1.047–16.957, P = 0.043) continued to be associated with an increased risk of in-hospital mortality of acute PE. CONCLUSION: A simple determination of the PaO(2)/FiO(2) ratio at <265 may provide important information on admission about patients’ in-hospital prognosis, and PaO(2)/FiO(2) ratio < 265, history of cancer, and risk stratification are predictors of in-hospital mortality of acute PE.