Dr. William DeCampli, pediatric cardiac surgeon at Arnold Palmer Hospital for Children, Orlando Health, talks about monitoring blood during surgery.
Interview conducted by Ivanhoe Broadcast News in 2023.
Why is it important to keep an eye on and monitor blood during surgery?
DeCampli: The issue with blood handling during cardiac surgery is that patients that need open heart surgery have to go on the heart-lung machine, which means that blood is actually traveling outside the body into an artificial pumps system with a lot of artificial tubing that can cause the blood to clot. If the blood clots, the patient won’t survive, so we need to thin the blood and keep it thin during the entire course of the operation. In order to know that it’s not going to clot, we need a way of monitoring the status of the blood and determining if it is thin enough or beginning to be prone to clotting.
What’s the problem with the clotting? Are you specifically working with children?
DeCampli: Yes, the problem is that we have a set of conventional measurements that we can make during the course of the operation, but these measurements in order to assess the tendency for blood to clot, have to involve drawing blood from the patient, putting it in the right tube, labeling the tube, sending it to the lab, waiting for the assay to be measured, and waiting again for the result to come back. The problem is that that results in a time delay.
Does that mean some of these surgeries are hours long? Would you have to take a couple of those or do you just continually take samples?
DeCampli: Yeah, it’s conventional to be taking samples roughly every 20 to 30 minutes. Some of these operations are major reconstructions, especially in congenital heart defects, we would be drawing four to six rounds of those tests, but each one is delayed in getting back the answer, so all the while we don’t know what’s going to happen with the blood until we get the answers back.
What happens if the blood starts to clot? What’s the risk to the child?
DeCampli: The risk to the child is a fatality.
Is it a stroke?
DeCampli: At the minimum, it would be a stroke, but if blood clots in the heart-lung machine, then the heart-lung machine will stop working.
Is this a rare occurrence? Is this something that is always on your mind?
DeCampli: Yes, It’s a pretty infrequent occurrence now because we give a drug called heparin that thins the blood and we give large doses of it during open heart surgery, and then we monitor its levels every 20 to 30 minutes. This is not something that happens frequently, but when it does happen, it can be fatal, and the idea is to prevent virtually any chance of this ever happening.
How are you doing that?
DeCampli: That’s where the new idea comes in. Back in 2017, I met Aristide Dogariu, who is in the College of Optics and Photonics at UCF. He was doing some really interesting work, monitoring the thickness of blood using light. He shines the light of a proper color onto blood and is able to measure the way that red blood cells are able to move about in the plasma portion of blood, which is the liquid part of the blood. It occurred to me that there might be a relationship between the thickness of blood, which is what he was measuring, and the tendency for blood to actually begin clotting. In other words, the early stage of clotting involves a thickening of the blood that Dr. Dogariu could actually measure. I then said, let’s take this technology directly into the operating room and try it out, and that’s exactly what we did in 2018 with a very surprising result.
We’ll get to the result, but how does it work exactly?
DeCampli: What we basically do is the light is transmitted along a very tiny optical fiber, something you can hardly see with the naked eye. It’s a very small instrument, but it gets inserted into the blood circuit during the conduct of open heart surgery. It lies within the blood and the light is shining on the blood, then that same optical fiber receives the signal that comes from the red blood cells as the light literally reflects off it.
Is the monitor put in the heart-lung machine area or in the infant?
DeCampli: So far, experiments have had it go into a side port of the tubing of the heart-lung machine, so it’s not directly in the patient, but it’s directly in the patient’s bloodstream.
Which is even better?
DeCampli: Yes.
What have been your results?
DeCampli: The results surprised us, we found a very strong correlation between the measurements we were getting and the values of these conventional tests that we have been running for years. Every 20 to 30 minutes, we withdraw our blood sample to get the usual measurements, and we would compare those measurements with what we were seeing with our probe, and they matched up very well as there were changes in the conventional measures of clotting, there was an exact correlation between that and the change in the measurements that we saw using the light source.
Was that 100 percent the same?
DeCampli: It was close enough to be very significant. Nothing is ever perfect in a first-time experiment, but it was better than we thought and it was good enough for the journal Nature to publish the following year.
What’s next for this?
DeCampli: We have plans now to extend our experimentation into adults because there are many more adults that undergo cardiac surgery than there are babies and children, and that’s where we think the real impact of this device can be ultimate. Our current plan is to begin a study very soon in adults where we are basically going to follow a very similar protocol to the one that we followed in the pediatric experiment and see what we get. Adults are not the same as children, their coagulation and clotting system is a little different because they are older patients, and we’re just not sure whether this will work in adults yet, that’s why we have to try it.
Is it going to be a study contained here or national?
DeCampli: This again will be local with a collaboration between Orlando Health and UCF.
Do you think this could change the way? Do you see this as the future?
DeCampli: It’s interesting that because I’m a heart surgeon, we’ve emphasized the application of this technique in open heart surgery, I think it may have an impact on the conduct of open heart surgery because not only can this test measure the tendency for blood to clot, but it can also measure the tendency for blood to fail to clot so that at the end of an open heart operation when we’re trying to make sure there’s no residual bleeding. We want to make sure the clotting and coagulation system in the bloodstream is back to normal. This technique can also measure the return to normal clotting and coagulation.
I think also when you’re thinking about a machine, or you don’t have to have someone go to the lab, you don’t have to have lab work, it has to save money and time right?
DeCampli: Absolutely, but most importantly, we think that it’ll be safer for the patient. I’ll mention one more thing, this technique can be extended to other specialties in medicine and to other disease states, for example, patients who come in having had trauma often have substantial blood loss, and along with that blood loss comes the tendency for the blood to not clot properly. We are imagining a catheter that we have designed on paper so far, but hope to really develop it that can actually be placed in a patient to continuously monitor clotting and coagulation during resuscitation from severe trauma. In the intensive care unit, patients who have a serious infection can also undergo real problems with clotting and coagulation, an example is COVID. COVID in severe cases leads to a state of what we call hypercoagulability, which means that the blood tended to clot abnormally, and these patients would end up sending blood clots to the brain or to the lungs, and that was a cause of death in some COVID patients. Now, if we could have continuously monitored the clotting and coagulation status of those patients, we may have been able to intervene more quickly before something catastrophic happened, and we believe that this technique, this technology may enable that.
END OF INTERVIEW
This information is intended for additional research purposes only. It is not to be used as a prescription or advice from Ivanhoe Broadcast News, Inc. or any medical professional interviewed. Ivanhoe Broadcast News, Inc. assumes no responsibility for the depth or accuracy of physician statements. Procedures or medicines apply to different people and medical factors; always consult your physician on medical matters.
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