Please see Bibliography of References for a list of abstracts, manuscripts and posters.
Mozina H, Strahovnik I, Podbregar M. Int Care Med. 2006;32(Supp 1):S290. Abstract 1128.
Introduction: It was previously shown that thenar muscle tissue oxygen saturation during stagnant ischemia decreases slower in septic shock patients compared to patients with severe sepsis, localized infection and healthy volunteers (1). Aim of study was to determine skeletal muscle oxygen kinetics in a group of patients with low cardiac output and to relate it to their central haemodynamics and outcome.
Methods: Thenar muscle tissue saturation (StO2) was measured by near infrared spectroscopy before and during upper arm ischemia-reperfusion test (UIRT) in patients with primary heart disease and circulatory failure, and in healthy volunteers. Muscle oxygen consumption (mVO2Nirs) was estimated with StO2 decrease during UIRT (ÄdownStO2) or calculated using following formula: mVO2Nirs =ÄdownStO2*Tissue Hemoglobin Index.
Results: In patients with preserved muscle oxygen extraction ratio (mOER) basal StO2 positively correlated to central venous hemoglobin saturation (ScvO2) (r=0.696, p=0.002); basalStO2 underestimated ScvO2 (bias: 9.0, precision: 4.6, 95% Cl limits of agreement: -0-2, + l8.2%). Survivors had higher muscle oxygen consumption compared to non-survivors (128±49 vs. 67±40, p=0.001). ÄdownStO2 (exp (B):0.777; CI 95%: 0.639, 0.945; p=0.012) and Sequential Organ Failure Score (exp (B): 0.292;CI 95%: 0.133, 0.639; p=0.002) were the only independent predictors of survival. In low flow state clinical important difference was found between ScvO2 and mixed venous hemoglobin saturation (SvO2) (bias: 10.8%, precision: 8.75%, 95%CI: -6.7%, + 28.3%).
Conclusion: Basal StO2, mOER and muscle oxygen consumption allow prediction of muscle tissue behavior in low flow states due to combined cardiogenic and septic circulatory failure. Low muscle oxygen consumption predicts worst outcome. Low basal StO2 could estimate ScvO2 in patients with preserved mOER. High discrepancy between ScvO2 and SvO2 is present in low flow state.
References: 1. Pareznik R, Voga G, Knezevic R, Podbregar M. Changes of muscle tissue oxygenation during stagnant ishemia in septic patients. Intensive Care Med 2006; 32;8.