Please see Bibliography of References for a list of abstracts, manuscripts and posters.

Other Studies

Effect of anemia on StO₂ and tissue deoxygenation rate during ischemia.

Meznar M, Pareznik R, Voga G. Crit Care. 2009;13(Suppl 1):P238.

Introduction: The hypothesis was that anemia, independently of hemodynamic stability, affects StO₂ and deoxygenation rate during stagnant ischemia. 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 lower tissue oxygen saturation. The rate of tissue deoxygenation during ischemia is dependent on oxygen consumption and on amount of oxygen available in the tissue.(1)

Methods: In prospective observational study we included 340 pts in the medical ER. On admission StO₂ and the tissue deoxygenaion rate during ischemia were measured by NIRS. Pts were divided into 4 groups according to hemoglobin concentration and hemodynamic (HD) stability: group 1 (non anemic, HD stable pts), group 2 (anemic, HD stable pts), group 3 (non anemic, HD unstable pts), group 4 (anemic, HD unstable pts). Differences in StO₂ and the rate of tissue deoxygenation were analized.

Results: Anemic groups had significantly lower Hb concentration (g/l) compared to nonanemic (138±16 vs 76.5±15, p<0.001). HD unstable groups had significantly higher lactate levels (mmol/l) compared to HD stable groups (1.6±0.6 vs 3.9±1.6, p<0.001).The results are shown in table 1. StO₂ in groups 2 and 3 was comparable, while the difference in deoxygenation rate in these groups was significant (p=0.007).

Conclusions: Anemia significantly affects StO₂ and deoxygenation rate. It probably contributes to lower StO₂ equaly as HD instability. In contrast to HD instability, anemia causes more rapid deoxygenation during ischemia.

References:

Creteur J: Muscle StO₂ in critically ill patients. Curr Opin Crit Care. 2008 Jun;14(3):361-6

Table 1: