Obesity was associated with a significantly longer mean half-life of oxygen extraction decay compared to normal BMI (18.8 s vs 12.2 s; P<0.004).
Observational (n=24)
Vasomotion in cutaneous microcirculation may act as a mechanism for red blood cells to sense local tissue hypoxia and improve perfusion, with altered oxygen extraction kinetics observed in obese individuals.
Absolute Event Rate: 18.8% vs 12.2%
p-value: p=< 0.004
Vasomotion is defined as a spontaneous local oscillation in vascular tone whose function is unclear but may have a beneficial effect on tissue oxygenation. Optical reflectance spectroscopy and laser Doppler fluximetry provide unique insights into the possible mechanisms of vasomotion in the cutaneous microcirculation through the simultaneous measurement of changes in concentration of oxyhemoglobin (HbO(2)), deoxyhemoglobin (Hb), and mean blood saturation (S(mb)O(2)) along with blood volume and flux. The effect of vasomotion at frequencies 29.3°C (X(2) = 6.19, P 29.5 kg/m(2)) of 18.8 s was statistically significant (Mann Whitney, P < 0.004). The S(mb)O(2) fluctuated spontaneously in this saw tooth manner by an average of 9.0% (range 4.0-16.2%) from mean S(mb)O(2) values ranging from 30 to 52%. These observations support the hypothesis that red blood cells may act as sensors of local tissue hypoxia, through the oxygenation status of the hemoglobin, and initiate improved local perfusion to the tissue through hypoxic vasodilation.
Thorn et al. (Sat,) conducted a observational in Healthy (n=24). Obesity (BMI >29.5 kg/m2) vs. Normal BMI (<26.0 kg/m2) was evaluated on Mean half-life of the decay in SmbO2 (measure of oxygen extraction) (p=< 0.004). Obesity was associated with a significantly longer mean half-life of oxygen extraction decay compared to normal BMI (18.8 s vs 12.2 s; P<0.004).