Effect of anemia on tissue oxygenation saturation and the tissue deoxygenation rate during ischemia

Abstract

ntroduction The hypothesis was that anemia, independently of hemodynamic stability, affects tissue oxygenation saturation (StO2) and the deoxygenation rate during stagnant ischemia. The blood hemoglobin concentration is determinant of oxygen delivery. In anemic patients, oxygen delivery decreases and oxygen extraction is increased. This leads to decreased venous hemoglobin saturation and a lower tissue oxygen saturation. The rate of tissue deoxygenation during ischemia is dependent on oxygen con- sumption and on the amount of oxygen available in the tissue [1]. Methods In a prospective observational study we included 340 patients in the medical emergency room. On admission, StO2 and the tissue deoxygenation rate during ischemia were measured by near-infrared spectroscopy. Patients were divided into four groups according to hemoglobin concentration and hemodynamic (HD) stability: Group 1 (nonanemic, HD-stable patients), Group 2 (anemic, HD-stable patients), Group 3 (nonanemic, HD-unstable patients), Group 4 (anemic, HD-unstable patients). Differences in StO2 and the rate of tissue deoxygenation were analyzed. Results Anemic groups had a significantly lower hemoglobin concentration compared with nonanemic groups (138 ± 16 vs. S98