Splanchnic perfusion evaluation during hemorrhage and resuscitation with gastric near-infrared spectroscopy

Objective: The purpose of this study was to use a prototype side-illuminating near-infrared spectroscopy (NLRS) nasogastric probe to continuously measure changes in gastric tissue oxygen saturation (Sto(2)) in a pig hemorrhage model, Methods: Swine (n = 12; 6 per group) underwent laparotomy and placement of a gastric MRS probe, jejunal tonometer, superior mesenteric artery (SMA) flow probe, and a portal vein catheter, Animals underwent hemorrhage (28 mL/kg) t = 0 to 20 minutes (where t = time). Pigs in group I were resuscitated (t = 20-40 minutes) with lactated Ringer's solution (84 mL/kg), whereas group II had no resuscitation. Results: A significant decrease in mean arterial pressure and SMA now was observed after hemorrhage, SMA pow significantly correlated in group I with both NIRS Sto(2) (r = 0.58, p = 0.0001) and regional CO2 (r = -0.54, p = 0.0001). In group II, superior mesenteric flow correlated with MRS Sto(2) (r = 0.30, p = 0.03), but not regional CO2 (r = -0.23, p = 0.09). Conclusion: Direct measurement of tissue oxygen saturation with a prototype side-illuminating near-infrared spectroscopy gastric probe appeared to rapidly reflect changes in splanchnic perfusion.