BACKGROUND: Noninvasive evaluation of muscle perfusion using near-infrared spectroscopy (NIRS) coupled with a vascular occlusion test (VOT) may provide an early and simple marker of altered perfusion and microcirculatory function in sepsis. OBJECTIVE: The aim of the study was to compare the time-course of NIRS-derived variables with systemic measures of perfusion in an experimental model of peritonitis. METHODS: Peritonitis was induced in eight anesthetized, mechanically ventilated, adult sheep (24-34 kg), by injecting autologous feces into the peritoneal cavity. Animals were followed until death or for a maximum of 30 h. Muscle tissue oxygen saturation (StO2) was determined using NIRS on the right posterior leg and arterial VOTs were performed by intermittent intra-aortic balloon inflation. Microdialysis was used to measure muscle lactate and pyruvate levels. RESULTS: Muscle StO2 was significantly lower than baseline values from 8 h after sepsis induction, but with considerable intersubject variability. The NIRS VOT ascending (Asc) slope decreased to values <120%/min in most animals from 12 h after sepsis induction. Muscle lactate/pyruvate ratios were higher than baseline from 16 h after sepsis induction. Mixed venous oxygen saturation (SvO2) decreased to <70% and blood lactate levels increased to >2 mmol/L in most of the animals only 24 and 28 h after sepsis induction, respectively. Muscle NIRS StO2 correlated strongly with femoral venous oxygen saturation (r = 0.820) and moderately with SvO2 (r = 0.436). CONCLUSIONS: The muscle NIRS Asc slope after a VOT is altered earlier than global markers of tissue hypoperfusion during sepsis. This simple noninvasive test can detect early changes in peripheral perfusion in sepsis.
BACKGROUND: Noninvasive evaluation of muscle perfusion using near-infrared spectroscopy (NIRS) coupled with a vascular occlusion test (VOT) may provide an early and simple marker of altered perfusion and microcirculatory function in sepsis. OBJECTIVE: The aim of the study was to compare the time-course of NIRS-derived variables with systemic measures of perfusion in an experimental model of peritonitis. METHODS:Peritonitis was induced in eight anesthetized, mechanically ventilated, adult sheep (24-34 kg), by injecting autologous feces into the peritoneal cavity. Animals were followed until death or for a maximum of 30 h. Muscle tissue oxygen saturation (StO2) was determined using NIRS on the right posterior leg and arterial VOTs were performed by intermittent intra-aortic balloon inflation. Microdialysis was used to measure muscle lactate and pyruvate levels. RESULTS: Muscle StO2 was significantly lower than baseline values from 8 h after sepsis induction, but with considerable intersubject variability. The NIRS VOT ascending (Asc) slope decreased to values <120%/min in most animals from 12 h after sepsis induction. Muscle lactate/pyruvate ratios were higher than baseline from 16 h after sepsis induction. Mixed venous oxygen saturation (SvO2) decreased to <70% and blood lactate levels increased to >2 mmol/L in most of the animals only 24 and 28 h after sepsis induction, respectively. Muscle NIRS StO2 correlated strongly with femoral venous oxygen saturation (r = 0.820) and moderately with SvO2 (r = 0.436). CONCLUSIONS: The muscle NIRS Asc slope after a VOT is altered earlier than global markers of tissue hypoperfusion during sepsis. This simple noninvasive test can detect early changes in peripheral perfusion in sepsis.
Authors: Elizabeth C Schroeder; Thessa I M Hilgenkamp; Wesley K Lefferts; Nadia Robinson; Tracy Baynard; Bo Fernhall Journal: Am J Physiol Regul Integr Comp Physiol Date: 2019-09-25 Impact factor: 3.619
Authors: Frédéric Michard; Manu Lng Malbrain; Greg S Martin; Thierry Fumeaux; Suzana Lobo; Filipe Gonzalez; Vitor Pinho-Oliveira; Jean-Michel Constantin Journal: Anaesth Crit Care Pain Med Date: 2020-08-09 Impact factor: 4.132