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 [PrCO(2)]) tonometer, superior mesenteric artery (SMA) flow probe, and a portal vein oxygen saturation (SpvO(2)) catheter. A muscle NIRS probe was placed on the front limb. After randomization, Group 1 underwent hemorrhage and resuscitation. Group 2 had no hemorrhage or 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 PrCO(2) 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 perfusion respectively during hemorrhage and ACS.