The nightmare of any surgeon performing abdominal surgery is not to immediately notice any suture leakage. It's like sewing a balloon with a hole in it and then inflating it: if the needle left a small hole, you won't see it until you start to feel the air blowing out. researchers ofSwiss Federal Institute for Materials Science and Technology (Empa) and dell 'ETH of Zurich have developed a real "patch" in hydrogel which not only helps close the wound, but can quickly detect any leakage from stitches inside the abdomen.
A "magic" patch that saves lives
The so-called anastomotic leak, which can occur when surgeons remove a section of intestine and then stitch it up, can cause serious problems. Highly acidic stomach fluids may begin to leak into the abdominal cavity, causing tissue inflammation and infection (peritonitis). In some cases even life-threatening blood infections (sepsis).
Many times, these leaks are only discovered when patients start experiencing symptoms such as pain and fever, and their health is already seriously compromised.
Here's how to see the invisible
“All surgeons keep an eye on the surgical field during more complex procedures. Yet as soon as the abdominal cavity is closed, they are 'blind' and may not notice leaks until it's too late,” he says Alexandre Anthis, one of the authors of the study. That's where the magic patch comes into play.
The high-tech patch is composed of a layered hydrogel matrix, with carbonate salts inside that act as non-electronic sensors. When these salts come into contact with acidic digestive fluids, they decompose, producing bubbles of carbon dioxide that become trapped in the hydrogel patch.
These bubbles can be visualized with a simple ultrasound because they stand out from the surrounding tissue due to their high contrast.
But that is not all. In the presence of digestive fluids, the patch also changes shape, assuming a circular or linear one, easily detectable with a CT scan. This means it offers a "dual mode" of leak detection. They are in fact visible both with ultrasound and with CT (including CT with very low dose of radiation).
Laboratory tests
When testing pig models, the researchers found that the carbonates only reacted in the presence of acid, therefore reducing the likelihood of false positives. Depending on the area of the leak, the reaction occurred within minutes to hours, well before clinical signs of a leak became apparent.
The patch sticks tightly to the wound site, sealing it and preventing it from moving. This, say the researchers, also reduces the risk of post-surgery complications and shortens hospital stays.
More research is needed to determine the long-term durability of the hydrogel patch, but the researchers are confident the device will offer a cost-effective way to detect leaks quickly, allowing for timely treatment.
The results of the study were published in the journal Advanced Science and I'll link them here.
