Use of micro-lightguide spectrophotometry for evaluation of microcirculation in the small and large intestines of horses without gastrointestinal disease.

The research article discusses the use of micro-lightguide spectrophotometry to evaluate intestinal microcirculation in horses, highlighting its accuracy and effectiveness despite certain environmental and physical challenges.

Objective of the Research

• The study aimed to assess the effectiveness of a micro-lightguide tissue spectrophotometer in measuring tissue oxygenation and blood flow in the small and large intestines of horses under anesthesia.

Methods Used in the Research

• 13 adult horses without gastrointestinal disease were involved in the study.
• The horses were anesthetized and placed in a position with their backs facing up (dorsal recumbency).
• A ventral midline laparotomy, a surgical incision into the abdominal cavity, was performed.
• Segments of intestines were brought out (exteriorized) to obtain measurements.
• The researchers conducted spectrophotometric measurements of tissue oxygenation and regional blood flow of the jejunum (part of the small intestine) and pelvic flexure under various conditions to assess potential effects on measurement accuracy.
• Arterial oxygen saturation at the measuring sites was determined using pulse oximetry.

Results of the Research

• A total of 12,791 single measurements of oxygen saturation, the relative amount of hemoglobin, and blood flow were obtained.
• Errors were found in 381 of the 12,791 measurements (approximately 2.98%).
• Most of these errors occurred when surgical lights were directed at the measuring site, an error that was not eliminated by even covering the probe with the surgeon’s hand.
• No measurement errors were found when the probe was positioned on the intestinal wall with room light, at the mesenteric side (the part of the intestinal wall that is attached to the abdominal wall), or between the mesenteric and antimesenteric side.
• Values for blood flow demonstrated higher variability, which the researchers attributed to motion artifacts of the intestines.

Conclusion of the Research

• The researchers found the micro-lightguide spectrophotometry system easy to use for both the small and large intestines in horses and found it provided immediate evaluation of the microcirculation.
• The results highlighted the importance of conducting measurements using only room light and minimizing intestinal motion to improve accuracy.