Abstract

Rationale

Patients with acute dyspnea are a large heterogeneous patient group where initial management is important for outcome.

Objectives

The objective of the study is to investigate if venous blood gas parameters predict 1-year risk of readmission or death in patients admitted to the emergency department due to acute dyspnea.

Methods

We studied 283 patients with acute dyspnea and followed them up for 1 year regarding incidence of readmission or death.

Measurements and main results

In venous blood obtained immediately upon admission levels of total carbon dioxide (TCO₂), base excess (BE), potential hydrogen (pH), and partial pressure of carbon dioxide (pCO₂) were measured. In Cox proportional hazards models, patients belonging to top and bottom quartiles of TCO₂, BE, pH, and pCO₂ were compared to patients belonging to the 2 central quartiles and assessed for end point. After adjustment, top (hazard ratio [HR], 1.48; 95% confidence interval [CI], 1.08-2.04; P = .016) and bottom (HR, 1.54; 95% CI, 1.08-2.18; P = .017) quartiles of BE were associated with increased risk of readmission or death. The strongest predictor was top quartile of TCO₂ (HR, 1.68; 95% CI, 1.21-2.35; P = .002). In the combined analysis, top quartile of TCO₂ remained significantly related to the end point (HR, 1.59; 95% CI, 1.03-2.45; P = .035), whereas BE became nonsignificant. Comorbidities, for example, prevalent chronic obstructive pulmonary disease, did not explain the association. Neither pCO₂ nor pH predicted the end point.

Conclusions

A high value of TCO₂ appears to be an easily accessible marker for 1-year readmission or death in patients with acute dyspnea and may thus add clinically important information for risk stratification and follow-up strategies.