Peripheral tissue oxygenation improves during ED treatment of acute heart failure.

OBJECTIVE: The objective of the study was to quantitatively characterize peripheral tissue microvascular oxygenation during emergency department (ED) treatment of acute heart failure (HF).
METHODS: 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(M)s) were calculated, defined as SaO(2) - StO(2)/0.8*SaO(2), where SaO(2) is pulse oximetry-derived arterial hemoglobin saturation and StO(2) 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).
RESULTS: The OER(M) for the stable HF group (n = 45) was 0.65 (SE = 0.07). The pre- and posttreatment OER(M)s 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).
CONCLUSIONS: 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.