Flow Patterns Arterial
Flow Patterns Arterial
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is a low resistance. So organs like brain and kidney will have low resistance in their vascular bed, so they allow more blood flow to come. And in this type of flow the spectral waveform is typically

a sharp systolic peak, followed by thorough/g diastolic flow throughout the cardiac cycle. And this is also called as a monophasic flow. This is as against the high resistance flow, which is typically seen in the extremities where the arterial bed of the muscle offers a lot of resistance to the blood flow. And because of that resistance, after the systolic peak

there is a early diastolic reversal and then there is a forward diastolic flow for a variable length. So the high resistance flow is also called as a triphasic flow because there are three phases in this spectrum. Coming to the venous spectrum. So this is a venous spectrum which is acquired with

free breathing.

flow diverting is planning. When you're looking at images there are a lot of things that can happen during a Pipeline procedure and understanding what those are understanding what

your potential bailouts are very important. So does the patient have an anterior communicating already do they have a posterior communicating artery that you can access the aneurysm from another vessel in case you bugger up

the access that you have from the vessel that you're going through. How aggressive do you want to be. If a patient comes in with a giant cavernous aneurysm and their 85 years old and they have minimal symptoms from it and you can't safely

and easily get through the outflow of that aneurysm do you want to try to go from the other side across the AComm and down into the internal carotid artery in order to access that aneurysm or you want to just leave it

alone. Do you want to consider doing a balloon test occlusion to determine if the patient can just tolerate having that blood vessel sacrificed in case you need to shut it down. And then you want to make

sure that you have all the equipment available to perform your bail out. So we need to be able to pull the device out if we have to. So microsnares alligator retrievers balloons to open up narrowings or

stenoses in the stent. Having all that stuff available are all very important parts of the pre procedural planning. Whenever I go to a facility with a physician to talk through the case with him that's one of the things that we

talk about is...okay what are our planning strategies what are our bailout strategies what equipment do we have available to get us out of trouble.

asymptomatic now bilateral CAS and you're going to say well he's 73 so he's

not high risk by age alone but what's a high-risk criteria and so bilateral lesions will qualify you as high-risk. Both sides are greater than seventy percent. And again CTA done with calcium in the arch. Calcium here

which looks not very favorable. Here's the right-sided lesion which actually was not as bad as the left side occlusion. So again done with the TCAR in the OR. And there's the final

Lessons learned during various past US military operations have really advanced our knowledge of vascular trauma surgery and these techniques can be translated to surgical practices and trauma centers

around the country and the world. Historically speaking military wartime experience gave us specific lessons and techniques that were translated into civilian surgery and critical care. Starting from the Vietnam era Korean

Conflict down to now. But as our war front is escalated on two fronts both in Iraq and Afghanistan and now some other places within the Middle East our military wartime experience has kind of had to borrow some things from civilian

in order to provide a less invasive and somewhat rapid control of hemorrhage where it relates to vascular trauma. The paradigm as far as endovascular treatment of vascular injuries in the battlefield and military trauma has kind

of changed. There have been at BAMC in San Antonio as well as at Fort Detrick in Maryland several areas of research that has been ongoing as far as surgical vascular trauma are concerned .And working in close concert with civilian

sector and industry there have been vast efforts that have been made to try to improve our vascular care especially where it relates to trauma in the battlefield. You can see that from conflicts dating back to World War II vascular

trauma has been commonplace. Back in those days there was no protective armor as we have now and thoracic trauma as well as abdominal vascular trauma were pretty much life-threatening and morbidity and mortality were extremely

high. Korean War very similar. Surgical trauma started making its way into the research sector and based on lessons learned here there was a big push within the army to develop a specific group of researchers

to look into these patterns of trauma. Vietnam war of course with improved medevac casevac capabilities with helicopters and getting patients injured at the scene to an area for treatment really improved their capability to save

lives and limbs both. And of course in the global war on terrorism both in OYF and OEF...or Operation Iraqi Freedom and Enduring Freedom... this is just escalated to a point where ability to get an injured soldier from

the battlefield to a treatment area is very rapid and moving up the escalon of treatment centers and treatment facilities within the battlefield to conus or continental United States is pretty rapid well-organized and develop

now. In my experience this is our base where we were...just to kind of give you an illustrative example kind of how spartan and remote we're located. We were what's called a level-two facility. A level two facility is basically what's called a

forward surgical team where we work in concert with special operations and also infantry units in the actual area of operations to be able to receive combat casualties by helicopter. Right behind this T wall is here was where the

helicopter would land and bring them straight into this tent which were basically set up as modular units with a basic operating room set up with two tables you can see it's pretty rudimentary in this picture. Those were

basically the front lines. Where we going to treat the soldiers to get their hemorrhage under control do damage control laparotomies and do things that were going to enable us to stabilize the patient enough to transport them to the

next level of care which would be called a level-three facility. Level three facilities have CAT scanners they have a higher level of care that can be offered to those patients. Most US soldiers are really treated expeditiously with

the goal of transporting them onwards to Germany and then the United States for definitive treatment. That didn't mean we didn't offer with immediate with life-threatening injuries some more definitive care but we try to move them

along as much as possible. But during the counterinsurgency mission back in 2011 when I had gone to Afghanistan they actually had made a push that we were treating local Nationals as well within our facilities and that got rapidly

exhausted because we had so many resources and we really were treating a lot of those folks definitively within the theater of operations. This is in Balad around 2009. Balad was

the largest air force base in Iraq which was a level-three facility. And in that facility you know we would have trauma...this is you know my crew out in the middle of the night...we would have multiple patients coming in. They

would treat them in this level three facility rapidly as much as possible with damage control airway breathing circulation and warming. And then we would move them onto the next level of care which was going to be either OR or

transport out to Germany basically a level-4 facility as we call it. This is a local national so he was treated within our hospital system for his injuries. You can see a basic setup. This is also in Balad where we had

digital subtraction angiography capabilities. But we really didn't have much in terms of guidewires catheters sheaths. I was using in angio caps basically putting them in femoral arteries and doing spot films all the

way down the leg to see if there was any vascular injury that could be identified. If I needed to treat him I didn't have the stents or balloons or anything to do it we had to do it open. But it gave us at least some diagnostic capability. Most

of the time this was only for peripheral vascular. In the intra-abdominal our capabilities were very limited. However that did change and that changed rapidly as vascular surgeons like myself and other trauma

surgeons realize that endovascular skills and techniques would be valuable in the battlefield. What happened in the Global War On Terrorism...I put a picture of myself but you can see that the body armor that I am wearing in this really

protects the torso and the pelvic areas as well as the head. So the real areas that are exposed are the arms and the legs. And that's why peripheral vascular trauma escalated so much. We had improved armored vehicles you know but improvised

explosive devices or IEDs as they're known were commonplace. And you could be sitting in a Humvee or you could be sitting in an MRAP you know IED blows up and it's the legs and the arms that are injured. Under sniper fire same thing

you know arms and legs. Torso was spared but so that really made us have to escalate our our ability to treat those extremity vascular injuries. And one of those things was tourniquet use. You know tourniquets have received good and

bad rap in the past you know. But all soldiers carry tourniquets in their

switch gears here and talk about

hemorrhagic stroke. Hemorrhagic stroke just like ischemic stroke comes in different flavors. So I'm going to talk about 2 key ones here today and they're all non-traumatic. The one shown here is a intraparenchymal hemorrhage. Meaning the hemorrhage is in the

substance of the brain. This starshaped hemorrhage is pretty classic for a subarachnoid hemorrhage which is within the folds of the brain not inside the brain but within the folds of the brain. And they both have a very high mortality

rate. Half the patients don't make it to the hospital. So let's start with the aneurysms. You've heard some about aneurysms today. An aneurysm is like a blister on a blood vessel wall that develops over time due to various

risk factors such as uncontrolled hypertension smoking binge-drinking recreational drug use...just a few of them that are known to be influential in their formation and growth. Back in the day you would have to have

an open brain surgery where they'd have to shave your hair make an incision peel the scalp back drill a hole in the bone and then go ahead and put this clip across the neck of the aneurysm excluded from

filling with blood. But since the advent of endovascular treatment you can do this transfemorally by taking a catheter parking it...microcatheter... into the aneurysm and deploying coils which are like miniature metal

slinkies so that you replaced the majority of the volume of the aneurysm with coils which prevents....which minimizes greatly entry of blood. And if you diminish pulsatile flow into the aneurysm you decrease the risk of

re-rupture.

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