Masseter muscle oxygen saturation is associated with central venous oxygen saturation in patients with severe sepsis

This monocentric prospective study was conducted to determine if tissue oxygen saturation measured non invasively over masseter muscle site (Masseter-StO2) can predict the central venous oxygen saturation (ScvO2) level in severe sepsis and septic shock.

Sixteen consecutive patients with severe sepsis (n = 10) or septic shock (n = 6) were included in this study. ScvO2 was measured on blood samples taken from the superior vena cava via the distal line of a central venous catheter. Masseter-StO2 was measured with a 25 mm depth infrared probe, applied and attached to the skin using transparent adhesive shields. Fifty-seven pairs of measures were obtained.

Mean ScvO2 was 76.5% (median 81, standard deviation 15, range [14-94]). Twenty percent of the ScvO2 measures were lower than 70%. Seven out of 16 patients had at least one measure of 70% or less. Mean Masseter-StO2 was 81% (median 91, standard deviation 18, range [29-98]). We found a significant association between ScvO2 and Masseter-StO2 (correlation coefficient 0.65, P < 0.01), however agreement was moderate.

In patients with severe sepsis or septic shock, non invasive recording of Masseter-StO2 was significantly associated with ScvO2 Further studies are required to determine the usefulness of Masseter-StO2 guided management of severe sepsis or septic shock.