Value of arterial blood gas analysis in patients with acute dyspnea: an observational study

We performed a post-hoc analysis of two different prospective studies to investigate the diagnostic and prognostic value of ABGA parameters in patients presenting to the ED with acute dyspnea.We enrolled 530 patients (median age 74 years). ABGA parameters were neither useful to distinguish between patients with pulmonary disorders and other causes of dyspnea nor to identify specific disorders responsible for dyspnea. Only in patients with hyperventilation from anxiety disorder, the diagnostic accuracy of pH and hypoxemia rendered valuable with an area under the receiver operating characteristics curve (AUC) of 0.86. Patients in the lowest pH tertile more often required admission to intensive care unit (28% vs 12% in the first tertile, P < 0.001) and had higher in-hospital (14% vs 5%, P = 0.003) and 30-day mortality (17% vs 7%, P = 0.002). Cumulative mortality rate was higher in the first (37%), than in the second (28%), and the third tertile (23%, P = 0.005) during 12 months follow-up. pH at presentation was an independent predictor of 12-month mortality in multivariable Cox proportional hazard analysis both for patients with pulmonary (P = 0.043) and non-pulmonary disorders (P = 0.038).ABGA parameters provide limited diagnostic value in patients with acute dyspnea, but pH is an independent predictor of 12 months mortality.Patients presenting to the emergency department (ED) with acute dyspnea require a rapid diagnostic work up to decide whether hospitalization or intensive care admission are needed and to guide further therapy [1]. Acute heart failure (AHF), exacerbation of chronic obstructive pulmonary disease (COPD), and pneumonia account for the majority of emergency consultations by patients with acute dyspnea [2,3]. As dyspnea is not a specific symptom, the rapid and accurate identification of the underlying causes remains a clinical challenge. Misdiagnosis causes morbidity and increases time to discharge and treatment cost [4]. In addition, treatment for one