Use of near-infrared spectroscopy to identify trends in regional cerebral oxygen saturation in horses.
Authors: McConnell E J, Rioja E, Bester L, Sanz M G, Fosgate G T, Saulez M N
Journal: Equine veterinary journal
Summary
# Editorial Summary: Near-Infrared Spectroscopy for Equine Cerebral Oxygenation Monitoring Perianaesthetic complications in horses may be linked to changes in blood flow and oxygen delivery to the brain, yet clinicians have lacked reliable tools to monitor cerebral perfusion during surgery. McConnell and colleagues applied near-infrared spectroscopy (NIRS)—a non-invasive optical monitoring technique long established in human anaesthesia—to measure regional cerebral oxygen saturation (rSO2) in six healthy horses across different physiological states: awake, sedated, anaesthetised under varying carbon dioxide conditions, and during recovery. The NIRS sensor reliably tracked rSO2 trends, revealing significant decreases in cerebral oxygenation during recovery compared to the awake state, though values remained stable during surgical anaesthesia itself regardless of ventilation strategy. Importantly, rSO2 showed moderate positive correlations with venous oxygen tension (r = 0.512) and arteriovenous oxygen saturation difference, suggesting that NIRS readings may serve as a practical proxy for cerebral oxygen extraction when direct venous blood sampling is unavailable. For practitioners managing anaesthetised horses, adopting NIRS monitoring could provide early warning of cerebral desaturation, enabling timely interventions before neurological complications develop—particularly valuable during the recovery phase when rSO2 values appear most vulnerable.
Read the full abstract on PubMed
Practical Takeaways
- •NIRS can be used as a non-invasive monitoring tool during equine anaesthesia to track cerebral oxygenation trends and detect potential desaturation events before they become critical
- •Decreasing rSO2 readings should prompt investigation of cerebral perfusion status and consideration of ventilation, oxygenation or cardiovascular adjustments
- •This technology may help reduce perianaesthetic complications in horses by providing real-time feedback on cerebral haemodynamics during surgery
Key Findings
- •NIRS successfully identified trends in regional cerebral oxygen saturation (rSO2) in horses across unsedated, sedated, anaesthetised and recovery periods
- •Significant decreases in rSO2 were observed between unsedated and post-anaesthetic periods (P<0.001), but no significant differences during intra-anaesthetic periods despite varying ventilation strategies
- •Positive correlations identified between rSO2 and venous oxygen tension (PvO2, r=0.512, P<0.001), suggesting cerebral oxygenation changes are reflected in venous blood gases
- •NIRS monitoring may provide early warning of cerebral desaturation events during equine anaesthesia, potentially enabling timely clinical intervention