Effects of intraluminal distention and decompression on microvascular permeability and hemodynamics of the equine jejunum.

This research investigates how expanding (distention) and then releasing (decompression) the equine jejunum – a part of the horse’s small intestine – impacts its blood flow, fluid movement, and cell dynamics. It suggests that these actions can cause low-flow tissue damage and swelling, potentially contributing to complications after surgery for blocked small intestines.

Methodology

• The study involved five healthy adult horses that underwent an exploratory laparotomy, a surgical procedure to visually examine the abdominal organs.
• Two sections of the jejunum, dubbed the “sham-operated” or “instrumented” segments, were identified.
• Baseline values of parameters such as blood flow, oxygen delivery, and microvascular permeability were noted.
• After this, the researchers caused distention in the experimental part of the jejunum, producing an intraluminal pressure of 18 cm H2O. This was maintained for 120 minutes, followed by decompression for the same duration.
• Measurements were taken at different stages and compared between control, sham-operated, and experimental segments.

Results

• The average blood flow in the jejunum was determined to be 21.4 ml/min per kg. Distention caused a significant decrease in blood flow to 13.4 ml/min per kg.
• Decompression led to a major increase in blood flow, to 340% of its baseline value.
• Intraluminal distention and subsequent decompression notably increased microvascular permeability, as noted by changes in the osmotic reflection coefficient.
• Oxygen supply and content decreased significantly when the jejunum was distended and subsequently increased during decompression.
• A significant increase in edema (fluid accumulation) and neutrophil (white blood cell) infiltration was noted after distention and decompression when compared to the sham-operated or control segments.

Conclusions

• The process of distention and decompression in the equine jejunum causes a condition called low-flow ischemia wherein reduced blood flow can lead to tissue damage.
• The study also found that this process leads to edema, increasing the risk of complications such as adhesions (abnormal tissue stickiness) and ileus (disruption of the intestine’s ability to contract) after surgery for small intestine obstructions.