Feasibility of the ForeSight tissue oximetry system for estimating cerebral and renal tissue oxygen saturation in anesthetized dogs during hyperoxia, normoxia, and hypoxia.

OBJECTIVE: To evaluate the feasibility of the ForeSight tissue oximetry system for assessing regional cerebral and renal tissue oxygen saturation in anesthetized dogs across 3 oxygenation states. METHODS: 6 anesthetized Beagles were included. ForeSight tissue oximetry sensors were applied to the cranium and left lateral abdomen to estimate regional cerebral oxygen saturation (rScO2) and regional renal oxygen saturation (rSrO2). The left dorsal pedal artery, right femoral vein, and right jugular vein were cannulated for arterial and venous blood sampling. The distal tips of the jugular and femoral venous catheters were positioned in the renal vein and the most cranial aspect of the internal jugular vein. During hyperoxia, normoxia, and hypoxia, 1-mL blood samples were collected simultaneously from all 3 sites and analyzed using a blood gas analyzer. Weighted reference oxygenation values (REF-CXB) were calculated. Correlation and agreement between REF-CXB and rScO2 or rSrO2 were assessed using repeated-measures correlation and Bland-Altman analyses. RESULTS: rScO2 demonstrated moderate correlation with cerebral REF-CXB (r = 0.70; P < .01) but poor agreement. In contrast, rSrO2 showed no correlation with renal REF-CXB (r = 0.09; P = .62) and poor agreement. CONCLUSIONS: rScO2 demonstrated moderate correlation with the blood gas-derived cerebral oxygen saturation reference estimate in anesthetized dogs, whereas rSrO2 did not reliably reflect the corresponding renal oxygen saturation reference estimate. CLINICAL RELEVANCE: Trend monitoring of cerebral oxygenation with the ForeSight system may provide an adjunctive tool for real-time assessment of cerebral oxygenation in dogs undergoing general anesthesia.