Use of near-infrared spectroscopy to identify trends in regional cerebral oxygen saturation in horses.

The research investigates the use of near-infrared spectroscopy (NIRS) to monitor changes in the regional cerebral oxygen saturation (rSO2) in horses during anesthesia. The study found that NIRS could detect changes in rSO2, making it a valuable tool for clinicians trying to prevent cerebral desaturation events during equine anesthesia.

Research Objective

• The research sought to determine the validity of Near-infrared spectroscopy (NIRS) for monitoring trends in regional cerebral oxygen saturation (rSO2) in horses.
• The researchers aimed to ascertain the correlation between rSO2 and venous oxygen tensions.

Methodology

• The study involved 6 healthy horses from whose dorsal sagittal sinus cerebral oxygen saturation was recorded using an oximeter sensor.
• The horses were subjected to different oxygen conditions such as unsedated, sedated and anaesthetised states.
• Values for rSO2, arterial and venous oxygen and carbon dioxide tensions were recorded in the different states.
• The data was analyzed using linear mixed-effects models and Pearson’s correlation coefficient.

Results

• The mean values for rSO2, arterial oxygen tension (PaO2), venous oxygen tension (PvO2), arterial carbon dioxide tension (PaCO2) and arteriovenous oxygen saturations (SavO2) showed significant variations across the different recording periods.
• Significant decreases in rSO2 were noted between the unsedated period and the periods post anaesthesia.
• No significant changes in rSO2 values were observed between the unsedated period and intra-anaesthesia periods or between different anaesthesia periods.
• Significant positive correlations were established between rSO2 and PaO2, rSO2 and PvO2, and rSO2 and SavO2.

Conclusions

• This study is groundbreaking as it is the first of its kind to identify trends in rSO2 in horses using NIRS.
• The positive correlation between rSO2 and PvO2 implies that changes in cerebral oxygenation could be reflected in PvO2.
• Near-infrared spectroscopy can be employed to monitor trends in rSO2 during equine anesthesia.
• Decreasing rSO2 values could function as early warnings, informing clinicians about potential cerebral desaturation events, indicating the need for intervention.