Oxygen tissue saturation is lower in nonsurvivors than in survivors after early resuscitation of septic shock.

Background: Growing evidence suggests that the microvascular dysfunction is the key element of the pathogenesis of septic shock. This study’s purpose was to explore whether the outcome of septic shock patients after early resuscitation using early goal-directed therapy is related to their muscle tissue oxygenation. Methods: Tissue oxygen saturation (StO2) was monitored in septic shock patients using a tissue spectrometer (InSpectra Model 325; Hutchinson Technology, Hutchinson, MN). For the purpose of this retrospective study, the StO2 values were collected at the first measurement done after the macrohemodynamic variables (mean arterial pressure, urine output, central venous saturation in oxygen) were optimized. Results: After the hemodynamic variables were corrected, no difference was observed between the nonsurvivors and survivors, with the exception of pulse oximetry saturation (94% [92–97%] vs. 97% [94 –99%], P 0.04). The StO2 values were significantly lower in the nonsurvivors than in the survivors (73% [68 – 82%] vs. 84% [81–90%], P 0.02). No correlations were found between the StO2 and SpO2 (P 0.7). Conclusions: In septic shock patients, tissue oxygen saturation below 78% is associated with increased mortality at day 28. Further investigations are required to determine whether the correction of an impaired level of tissue oxygen saturation may improve the outcome of these patients. IN septic shock, guidelines recommend an early correction of mean arterial pressure, urine output, and central or mixed venous saturation in oxygen. 1 However, growing evidence suggests that the microvascular dysfunction is the key element in sepsis. 2 This dysfunction may be associated with impaired outcome. 3 At first glance, the correction of macrohemodynamics does not preclude whether or not the microvascular dysfunction continues. Near-infrared spectroscopy is a noninvasive monitoring, providing real-time feedback. 4 Near-infrared spectroscopy monitors only vessels with a diameter of less than 1 mm because the high concentration of blood in arteries and veins makes photon emergence unlikely. Near-infrared light (600 – 800 nm) easily crosses biologic tissues and is absorbed by hemoglobin, myoglogin, and oxidized cytochrome, as described elsewhere. 5 This tool can quantify microvascular dysfunction in patients with septic shock. 6 One can hypothesize that near-infrared spectroscopy can detect a potential microvascular dysfunction in the patients adequately resuscitated from a macrohemodynamic standpoint. The purpose of this study was to explore whether the outcome of the septic shock patients after early resuscitation using early goal-directed therapy was related to their muscle tissue oxygenation.