Clinical significance of acid–base balance in an emergency setting in patients with acute heart failure

Abstract Background and purpose The role of an arterial blood gas analysis in acute heart failure (AHF) remains unclear. The acid–base balance could help to treat AHF, and it might help to distinguish different types of AHF, while it might be associated with the AHF prognosis. The present study was conducted to determine the relationship between the arterial blood gas sample at the time of hospital admission and clinical findings on admission, outcomes. Methods and results Six hundred twenty-one patients with AHF admitted to the intensive care unit were analyzed. Patients were assigned to an alkalosis group ( n = 99, pH > 7.45), normal group ( n = 178, 7.35 ≦ pH ≦ 7.45), and acidosis group ( n = 344, pH < 7.35). The clinical findings on admission and outcomes (in-hospital mortality and any-cause death within 2 years) were compared between the three groups. The white blood cell counts (WBC), serum levels of total protein, albumin, and glucose were significantly lower, and the serum levels of C-reactive protein (CRP) and total bilirubin were significantly higher in the alkalosis group. Patients with orthopnea were significantly fewer, and the systolic blood pressure (SBP) and heart rate (HR) were significantly lower in the alkalosis group. The results of a multivariate logistic regression model for in-hospital mortality found that alkalosis was an independent risk factor ( p = 0.017, odds ratio: 2.589; 95% confidence interval: 1.186–5.648). The Kaplan–Meier curves showed the prognosis for any-cause death to be significantly poorer in the alkalosis group than in the normal group ( p = 0.026). Conclusions The factors associated with alkalosis AHF were high CRP, bilirubin, and low WBC, glucose, total protein, and albumin. The patients with alkalosis AHF were less likely to have orthopnea with low SBP and HR. They suggested that the patients with alkalosis AHF might have experienced AHF for a few days and were associated with high mortality.