How "Captain Hemo" Came to be
or how the hemopump was "born"
History
With today's sophisticated and general clinical acceptance of heart pumps used to assist a failing ventricle, based on rotary blood pumps, it might seem to those who did not live through the development stages of these devices to imagine a time when such ideas were considered crazy or almost medical blasphemy. The challenges technically were fierce, as long held beliefs regarding rotary pumps proved difficult to overcome. It took about 30 years from the very beginning of rotary blood pump technology to gain acceptance as an effective device for a treatment of end stage heart failure. This is a summation of the recollection of writings and conversations with the other collaborators of this journey, O.H. Frazier, Leonard Golding and Kenneth Butler.
Rotary Blood Pump Development
"During my career I have been a part of some amazing successes and soul crushing failure." - Richard Wampler, MD
When first intrigued by the possible use of blood pumps as a senior medical student in 1074, Richard Wampler became aware of many strongly held negative beliefs regarding the use of rotary blood pumps for MCS (Mechanical Circulatory Support). The common belief was that in order for an device to be effective it would have to produce a pulsatile circulation. Why? It was reasoned based on millions of years of evolution in living creatures of all kinds that had pulsatile circulation, and that must be nature's way of telling us that it had to have physiologic reasons. On top of that, it had been shown that the chance of death among heart bypass patients increased dramatically after only two hours of continuous flow bypass during heart surgery. So, logically, it seemed the idea of long term pulseless support was an absurd notion.
There was also a belief that by nature a rotary pump would act like a "blender" for the blood that would change the composition of Hemoglobin that could cause a severe renal injury, and also potential loss of red blood cells that would complicate further and result in hemolytic anemia. Despite the lack of actual testing in this area, this was the prevailing belief system. So strong were these held beliefs that it was nearly impossible to have a reasonable conversation regarding the possibility. It was often stated that if hemolysis did not kill the patient then surely the non-pulsatile blood flow would. On top of all that there were enormous engineering challenges as well, with regard to sealing and formation of thrombus and denatured protein, leading to the ultimate seizure of the driveshaft.
Because of these hurdles, all efforts to create MCS devices strived to emulate the pulsing action found in natural functioning hearts. This was completely supported by the National Institute of Health, in spite of the additional challenges of large size, complexity, durability of flexing membranes and the need for artificial valves.
Perhaps a great irony in this thinking was the invention of fixed wing aircraft. At first inventors pursued a "like nature" approach to flying, creating machines that flapped wings and emulated birds. It took two bicycle mechanics from Dayton, Ohio to demonstrate that a fixed wing device was a better strategy. And the rest, as they say, is history.
Richard Has an Epiphany
Dr Wampler remembers very well the event in his life that caused him to follow the path of rotary blood pumps for circulatory support.
He had been fortunate that in his youth he had people around him who believed in him, even before he had gained confidence in himself. Of note was his grandfather, Luster Foster. Luster had lived in the time of the Great Depression, but somehow still maintained the positive attitude of a dreamer. Amazing to be like that during such a time of despair and broken dreams. He had lost his home, barely making it to support his young family, and even lost his first born child to pneumonia. The lessons he passed to Richard about many things stuck with him. Among those skills he passed was how to create things with wood.
But the most impactful thing that occurred was his passing due to heart disease, during Rich's junior year in medical school. Rich felt helpless to do anything to save him his fate, as his life slipped away. At first he didn't realize the profound impact this event would have on him or how it would drastically alter the path of his career.
The Secret of Success - Serendipity
Rich feels today that he would have accomplished very little if not for serendipity, which is a "gift" for discovering things, by accident or chance, while looking for something else. Like a "happy chance". Some might call it Karma, or cosmic coincidence. Regardless, it seemed to be a trait which permeated Rich's life, and one he feels quite blessed to carry. For him, it often spawned ideas and inspiration.
The pathway of his inventive journey is perhaps best described by a offshoot playful definition of serendipity - "serene stupidity". Rich tells of a comparison to the famous movie character Forrest Gump. Although Forrest was just a simple guy with good intentions, he happily stumbled into being a champion ping pong player, meeting three US Presidents and founding a multi-million dollar restaurant franchise. Rich always felt that in many ways, several of his accomplishments found him.
The Beginning
Because he planned to be a cardiac surgeon, all of the electives he took during his senior year in medical school were with cardiovascular training centers around the country. His interest in heart surgery, along with his curiosity, creativity, good dexterity, resourcefulness and a willingness to risk, he began to imagine rotary artificial hearts. He became convinced that a key component of a potential artificial heart would be a rotary pump. Looking back he isn't sure why he thought that would be a central component, especially since the prevailing thought amongst those most qualified in the field were counter to this thought process. Because of that, he certainly hadn't been educated with this premise, nor had any background that would have supported this notion. Instead it was his intuition that drove him in this direction, however against the grain, to believe that this was going to be the best way. Engineering was on his side though, offering critical advantages over pulsatile devices including:
Being that this thinking was so against the grain at the time, he initially kept his thoughts to himself. But, because he was a tinkerer, a doer if you will, he began to wrestle with making prototypes. Despite his lack of knowledge, he pushed forward.
Early builds were flawed of course, but each had some measure of success that encouraged Rich to continue forward. Some of the early prototypes are chronicled in the articles within this website.
Later, during his internship and residency, Rich spent a lot of time researching work on artificial hearts and left ventricular assist devices. Most research, as we've already mentioned, was focused on pumps attempting to emulate a pulse, but there was a bit of research available on rotary blood pumps too. It turns out some early work had been done even back when Rich was still in high school on the idea of rotary pumps being used for this purpose.
It also turns out that some work had been done with centrifugal pumps, due to their engineering advantages. In studies that followed this path, suspending disbelief regarding significant hemolysis, there were a number of canine experiments using centrifugal pumps for biventricular assistance. All the animals died within 15 minutes of severe pulmonary edema. That stopped that idea dead in its tracks. Fortunately for Rich, and for us, he did not become aware of that work until significant progress had been made in the area of rotary blood pump development. It may have been a huge deterrent in his continued pursuit of his ideas.
Since the prevailing concerns about hemolysis were paramount, Rich knew that the issue of tolerance to hemolysis was a critical component in design for a pump. He search diligently for studies that addressed this concern. There were studies that addressed hemolysis in patients where some seemed able to tolerate or compensate somehow the condition, but it wasn't quantified or understood adequately why this was. Despite this, it seemed to Rich that there was a potential design that might be implemented that would allow for acceptable levels of blood injury within the rotary driven pump pursuit.
It turns out that Rich's intuition was right. In canine tests conducted in 1965, it was reasonably shown that during infusion, except for episodes of sepsis, hemoglobin evaluation numbers came in at a very acceptable range. In 1970 a centrifugal pump called the Hemodyne Pump was developed in a collaboration with Medtronic and Berstein et. al.
By March of 1970 two acute human cases were reported. The patients were extremis and were supported for 9 and 5.5 hours respectfully. The first patient did show improvement and actually regained consciousness. However, due to unidentified blood loss created a situation that surgeons were unsuccessful in improving and subsequently the patient perished. The second patient followed a similar pattern, improving hemodynamics but gastrointestinal bleeding caused his death. The Hemodyne pump was ultimately abandoned due to a limited seal life, approximately one month. But the Hemodyne system did demonstrate the ability of a rotary pump to completely support systemic circulation with acceptable levels of blood injury and the viability of non-thoracotomy bypass.
The accomplishment was largely forgotten. It would be thirty years later that Dr Wampler would apply the innovation of transvalvular venticular access to the invention of the Hemopump.
Happy Chance
In 1976 fate stepped in. On a mission trip to a small village in Egypt called El Bayad, Rich discovered life and farming were very primitive there. One of the foremost needs of the villagers was to establish a safe water supply to deal with infection from parasitic liver flukes and childhood diarrhea. To seek a solution, Rich read up on well designs and, particularly, the concept of submersible pumps. These types of pumps reside below the ground in the water table and "push" water up to the surface.
While there, Rich was also witness to the use of crude Archimedes screw pumps to lift water from irrigation canals to water fields. The Archimedes screw evolved later with sophistication and modern materials to become turbine pumps and jet engines. It would be six years after this trip to El Bayad that Rich would connect the dots in his mind to come up with the invention of the Hemopump.
Rich discovered along the way on his inventive journey that it sometimes takes a while to connect the dots. He knew that while he was in Egypt, not once in the midst of that hot, desolate and primitive and wonderful place, did he ever think of pumping blood with an Archimedes screw. Nor did he consider that the principal of a submersible pump could just as well be a Hemopump sustaining the flow of lifeblood to an injured heart. It was not until 1982, six years removed from his trip to Egypt, that he found himself on a plane, a book in hand opened to a diagram of a submersible pump and Archimedes screw. The final piece came to him when he recalled Zwart's transvalvular ventricular access. It was then that serendipity and inspiration helped him connect the dots and the invention of an intravascular blood pump was born. His "Eureka" moment imagined a miniature intravascular pump placed inside, not outside the body or heart. Whether or not such an imagined device was actually technically feasible would take several years to determine. Working with Nimbus Medical engineers, and relying on his own engineering study years before at CSUS (CA State University at Sacramento), the Hemopump was born.
With today's sophisticated and general clinical acceptance of heart pumps used to assist a failing ventricle, based on rotary blood pumps, it might seem to those who did not live through the development stages of these devices to imagine a time when such ideas were considered crazy or almost medical blasphemy. The challenges technically were fierce, as long held beliefs regarding rotary pumps proved difficult to overcome. It took about 30 years from the very beginning of rotary blood pump technology to gain acceptance as an effective device for a treatment of end stage heart failure. This is a summation of the recollection of writings and conversations with the other collaborators of this journey, O.H. Frazier, Leonard Golding and Kenneth Butler.
Rotary Blood Pump Development
"During my career I have been a part of some amazing successes and soul crushing failure." - Richard Wampler, MD
When first intrigued by the possible use of blood pumps as a senior medical student in 1074, Richard Wampler became aware of many strongly held negative beliefs regarding the use of rotary blood pumps for MCS (Mechanical Circulatory Support). The common belief was that in order for an device to be effective it would have to produce a pulsatile circulation. Why? It was reasoned based on millions of years of evolution in living creatures of all kinds that had pulsatile circulation, and that must be nature's way of telling us that it had to have physiologic reasons. On top of that, it had been shown that the chance of death among heart bypass patients increased dramatically after only two hours of continuous flow bypass during heart surgery. So, logically, it seemed the idea of long term pulseless support was an absurd notion.
There was also a belief that by nature a rotary pump would act like a "blender" for the blood that would change the composition of Hemoglobin that could cause a severe renal injury, and also potential loss of red blood cells that would complicate further and result in hemolytic anemia. Despite the lack of actual testing in this area, this was the prevailing belief system. So strong were these held beliefs that it was nearly impossible to have a reasonable conversation regarding the possibility. It was often stated that if hemolysis did not kill the patient then surely the non-pulsatile blood flow would. On top of all that there were enormous engineering challenges as well, with regard to sealing and formation of thrombus and denatured protein, leading to the ultimate seizure of the driveshaft.
Because of these hurdles, all efforts to create MCS devices strived to emulate the pulsing action found in natural functioning hearts. This was completely supported by the National Institute of Health, in spite of the additional challenges of large size, complexity, durability of flexing membranes and the need for artificial valves.
Perhaps a great irony in this thinking was the invention of fixed wing aircraft. At first inventors pursued a "like nature" approach to flying, creating machines that flapped wings and emulated birds. It took two bicycle mechanics from Dayton, Ohio to demonstrate that a fixed wing device was a better strategy. And the rest, as they say, is history.
Richard Has an Epiphany
Dr Wampler remembers very well the event in his life that caused him to follow the path of rotary blood pumps for circulatory support.
He had been fortunate that in his youth he had people around him who believed in him, even before he had gained confidence in himself. Of note was his grandfather, Luster Foster. Luster had lived in the time of the Great Depression, but somehow still maintained the positive attitude of a dreamer. Amazing to be like that during such a time of despair and broken dreams. He had lost his home, barely making it to support his young family, and even lost his first born child to pneumonia. The lessons he passed to Richard about many things stuck with him. Among those skills he passed was how to create things with wood.
But the most impactful thing that occurred was his passing due to heart disease, during Rich's junior year in medical school. Rich felt helpless to do anything to save him his fate, as his life slipped away. At first he didn't realize the profound impact this event would have on him or how it would drastically alter the path of his career.
The Secret of Success - Serendipity
Rich feels today that he would have accomplished very little if not for serendipity, which is a "gift" for discovering things, by accident or chance, while looking for something else. Like a "happy chance". Some might call it Karma, or cosmic coincidence. Regardless, it seemed to be a trait which permeated Rich's life, and one he feels quite blessed to carry. For him, it often spawned ideas and inspiration.
The pathway of his inventive journey is perhaps best described by a offshoot playful definition of serendipity - "serene stupidity". Rich tells of a comparison to the famous movie character Forrest Gump. Although Forrest was just a simple guy with good intentions, he happily stumbled into being a champion ping pong player, meeting three US Presidents and founding a multi-million dollar restaurant franchise. Rich always felt that in many ways, several of his accomplishments found him.
The Beginning
Because he planned to be a cardiac surgeon, all of the electives he took during his senior year in medical school were with cardiovascular training centers around the country. His interest in heart surgery, along with his curiosity, creativity, good dexterity, resourcefulness and a willingness to risk, he began to imagine rotary artificial hearts. He became convinced that a key component of a potential artificial heart would be a rotary pump. Looking back he isn't sure why he thought that would be a central component, especially since the prevailing thought amongst those most qualified in the field were counter to this thought process. Because of that, he certainly hadn't been educated with this premise, nor had any background that would have supported this notion. Instead it was his intuition that drove him in this direction, however against the grain, to believe that this was going to be the best way. Engineering was on his side though, offering critical advantages over pulsatile devices including:
- Much smaller displaced and priming volume
- Simplicity with fewer (one) moving parts
- No need for artificial valves
Being that this thinking was so against the grain at the time, he initially kept his thoughts to himself. But, because he was a tinkerer, a doer if you will, he began to wrestle with making prototypes. Despite his lack of knowledge, he pushed forward.
Early builds were flawed of course, but each had some measure of success that encouraged Rich to continue forward. Some of the early prototypes are chronicled in the articles within this website.
Later, during his internship and residency, Rich spent a lot of time researching work on artificial hearts and left ventricular assist devices. Most research, as we've already mentioned, was focused on pumps attempting to emulate a pulse, but there was a bit of research available on rotary blood pumps too. It turns out some early work had been done even back when Rich was still in high school on the idea of rotary pumps being used for this purpose.
It also turns out that some work had been done with centrifugal pumps, due to their engineering advantages. In studies that followed this path, suspending disbelief regarding significant hemolysis, there were a number of canine experiments using centrifugal pumps for biventricular assistance. All the animals died within 15 minutes of severe pulmonary edema. That stopped that idea dead in its tracks. Fortunately for Rich, and for us, he did not become aware of that work until significant progress had been made in the area of rotary blood pump development. It may have been a huge deterrent in his continued pursuit of his ideas.
Since the prevailing concerns about hemolysis were paramount, Rich knew that the issue of tolerance to hemolysis was a critical component in design for a pump. He search diligently for studies that addressed this concern. There were studies that addressed hemolysis in patients where some seemed able to tolerate or compensate somehow the condition, but it wasn't quantified or understood adequately why this was. Despite this, it seemed to Rich that there was a potential design that might be implemented that would allow for acceptable levels of blood injury within the rotary driven pump pursuit.
It turns out that Rich's intuition was right. In canine tests conducted in 1965, it was reasonably shown that during infusion, except for episodes of sepsis, hemoglobin evaluation numbers came in at a very acceptable range. In 1970 a centrifugal pump called the Hemodyne Pump was developed in a collaboration with Medtronic and Berstein et. al.
By March of 1970 two acute human cases were reported. The patients were extremis and were supported for 9 and 5.5 hours respectfully. The first patient did show improvement and actually regained consciousness. However, due to unidentified blood loss created a situation that surgeons were unsuccessful in improving and subsequently the patient perished. The second patient followed a similar pattern, improving hemodynamics but gastrointestinal bleeding caused his death. The Hemodyne pump was ultimately abandoned due to a limited seal life, approximately one month. But the Hemodyne system did demonstrate the ability of a rotary pump to completely support systemic circulation with acceptable levels of blood injury and the viability of non-thoracotomy bypass.
The accomplishment was largely forgotten. It would be thirty years later that Dr Wampler would apply the innovation of transvalvular venticular access to the invention of the Hemopump.
Happy Chance
In 1976 fate stepped in. On a mission trip to a small village in Egypt called El Bayad, Rich discovered life and farming were very primitive there. One of the foremost needs of the villagers was to establish a safe water supply to deal with infection from parasitic liver flukes and childhood diarrhea. To seek a solution, Rich read up on well designs and, particularly, the concept of submersible pumps. These types of pumps reside below the ground in the water table and "push" water up to the surface.
While there, Rich was also witness to the use of crude Archimedes screw pumps to lift water from irrigation canals to water fields. The Archimedes screw evolved later with sophistication and modern materials to become turbine pumps and jet engines. It would be six years after this trip to El Bayad that Rich would connect the dots in his mind to come up with the invention of the Hemopump.
Rich discovered along the way on his inventive journey that it sometimes takes a while to connect the dots. He knew that while he was in Egypt, not once in the midst of that hot, desolate and primitive and wonderful place, did he ever think of pumping blood with an Archimedes screw. Nor did he consider that the principal of a submersible pump could just as well be a Hemopump sustaining the flow of lifeblood to an injured heart. It was not until 1982, six years removed from his trip to Egypt, that he found himself on a plane, a book in hand opened to a diagram of a submersible pump and Archimedes screw. The final piece came to him when he recalled Zwart's transvalvular ventricular access. It was then that serendipity and inspiration helped him connect the dots and the invention of an intravascular blood pump was born. His "Eureka" moment imagined a miniature intravascular pump placed inside, not outside the body or heart. Whether or not such an imagined device was actually technically feasible would take several years to determine. Working with Nimbus Medical engineers, and relying on his own engineering study years before at CSUS (CA State University at Sacramento), the Hemopump was born.
This website is dedicated to the journey of the Hemopump and it's creator, Dr Richard Wampler, who was subsequently coined "Captain Hemo". The site chronicles many of the articles that covered this breakthrough discovery and technology, from several angles and perspectives. It also strives to credit the many along the way those who assisted in this technology with testing and training for those heart surgeons who first used the device, and the brave patients and their families who allowed for this device to have a role in medical history.
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