Near-infrared spectroscopy reflects changes in mesenteric and systemic perfusion during abdominal compartment syndrome

Background. Continuous and minimally invasive near-infrared spectroscopy (NIRS)-derived gastric tissue oxygen saturation (GStO(2)) and muscle tissue oxygen saturation (MStO(2)) were evaluated in a clinically relevant porcine model of hemorrhagic shock and abdominal compartment syndrome (ACS). Methods, Phenobarbital-anesthetized swine underwent pulmonary artery catheter insertion for mixed venous oxygen saturation (SvO(2)) measurement and midline laparotomy to permit placement of a gastric NIRS probe, a jejunal (regional carbon dioxide [PrCO2]) tonometer superior mesenteric artery (SiMA) flow probe, and a portal vein oxygen saturation (SpvO(2)) catheter. A muscle MRS probe was placed on the front limb. After randomization, Group 1 underwent hemorrhage and resuscitation, Group 2 had no hemorrhage or res resuscitation. ACS was induced by peritoneal fluid infusion in both groups. A significant decrease in SMA flow, SpvO(2), GStO(2), SvO(2) and MStO(2) was observed after hemorrhage in Group 1 and with abdominal hypertension in both groups. Results. GStO(2) significantly correlated with SMA flow (Group 1: r(2) = 0.90; Group 2: r(2) = 0.83) and mesenteric oxygen delivery (mesenteric oxygen delivery, Group 1: r(2) = 0.73 Group 2. r(2) = 0.89. MStO(2) significantly correlated with SvO(2) (Group 1: r(2) = 0.99; Group 2: r(2) = 0.65 )and systemic oxygen delivery (SDO2, Group 1: r(2) = 0.60; Group 2: r(2) = 0.88). Tonometer-derived PrCO2 values did not change at any time point in either group. Conclusions. NIRS measurement of GStO(2) and MStO(2) reflected changes in mesenteric and systemic per fusion respectively during hemorrhage and ACS.