The objective of the study was to quantitatively characterize peripheral tissue microvascular oxygenation during emergency department (ED) treatment of acute heart failure (HF).

This prospective, observational study enrolled acutely decompensated HF patients presenting to an urban ED and stable, asymptomatic HF patients evaluated in an outpatient cardiology clinic. Stable, pre-ED treatment, and post-ED treatment microvascular oxygen extraction ratios (OER_Ms) were calculated, defined as SaO₂ − StO₂/0.8*SaO₂, where SaO₂ is pulse oximetry–derived arterial hemoglobin saturation and StO₂ is the tissue hemoglobin oxygen saturation measured with differential absorption spectroscopy. The OER_M measurements were analyzed using repeated-measures analysis of variance. Pulse oximetry, patient demographics, HF etiology, serum B-type natriuretic peptide, and hemoglobin were measured along with a visual analogue scale to assess patient baseline characteristics and response to ED treatment (P < .05 was considered significant for all testing).

The OER_M for the stable HF group (n = 45) was 0.65 (SE = 0.07). The pre- and posttreatment OER_Ms for the ED HF group (n = 46) were 0.92 (SE = 0.07) and 0.75 (SE = 0.06), respectively. Whereas the pretreatment ED OER_M was higher than the stable patient OER_M (P = .001), the posttreatment ED OER_M was not significantly different from the stable patient measurement (P = .271).

Oxygen extraction in acute HF is significantly increased, but approaches values found in the stable HF population after ED treatment. The OER_M may deserve closer examination as a possible goal-directed variable in the treatment of acute HF.