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

Objective: 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.

Methods: 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.

Results: 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.

Conclusions: 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.