Steady-state response characteristics of a pulse oximeter on equine intestine.

This study evaluates the performance of a pulse oximeter on different parts of the intestine in anesthetized horses, finding that there is no significant discrepancy in results based on location. It indicates that pulse oximetry oxygen values sourced from the jejunum and ileum, part of the small intestine, are slightly lower than those from other intestinal segments.

Study Methodology

• The researchers measured the steady-state response characteristics of a pulse oximeter.
• The testing was conducted on the different segments of the intestines— jejunum, ileum, cecum, left ventral colon, left dorsal colon, and descending colon—of seven healthy horses under halothane anesthesia.
• Arterial oxygen tension greater than 200 mm of Hg, end tidal carbon dioxide from 30 to 35 mm of Hg, and systemic mean arterial pressure greater than 70 mm of Hg were maintained during the test period.
• The probe placement on intestinal segments was over or not over visible subserosal or transmural vessels, and data was recorded.

Results and Insights

• There was no significant difference between median values for pulse oximeter oxygen saturations, pulsatile flow, and signal strength based on placement of the probe on a vessel area.
• The median values for pulse oximeter oxygen saturation were 93% for jejunum and ileum, and 95% for cecum, left ventral colon, left dorsal colon, and descending colon— slightly lower for the jejunum and ileum segments.
• The pulsatile flow rates varied minutely over the different segments but did not show any significant difference.
• Signal strength also varied across different segments, with the highest median value observed in the left ventral colon (75%) and the lowest in the jejunum and left dorsal colon (50% each).

Conclusions

• The results indicated that readings from a pulse oximeter aren’t significantly impacted by the specific part of the equine intestine where the readings are taken.
• However, pulse oximetry oxygen values from the jejunum and ileum areas of the intestine were observed to be slightly lower than those from other regions.

This research may be significant for veterinary procedures involving anaesthetized horses, as it provides insights about the performance of pulse oximeters in different areas of the horse digestive tract.