Monitoring tissue oxygen heterogeneities and their influence on optical glucose measurements in an animal model.

The purpose of this study was to characterize the heterogeneity of oxygen partial pressure in different adipose tissue zones and to assess the possibility of compensating these heterogeneities during optical glucose measurements. In this proof of concept study, the heterogeneity of oxygen partial pressure was determined in the adipose tissue of a pig by using 48 oxygen sensors in 3 zones of the abdominal region at two different blood oxygen levels. Sensor oxygen values correlated well with reference blood oxygen values and we identified heterogeneities in oxygen partial pressure among the defined zones of the abdominal region. Significant differences in the mean oxygen partial pressure were found when comparing the three abdominal zones but no significant differences were found when comparing two sensors located in close proximity (on one cannula). The low heterogeneity on one cannula allows the compensation of physiological oxygen variations for optical glucose measurements by using an additional oxygen sensor in close proximity to the glucose sensor. In addition, this setup can be used to continuously monitor tissue oxygenation e.g. in patients with adipose tissue dysfunction or serve limb ischemia.