Week Four Teachback: The Artificial Heart and Contact Lenses

Joel Benedict

University of Advancing Technology

HIS305-D09OCT16

Professor Josh Miller

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Introduction

A heartbeat and a blink happen in a microsecond thousands of times every day. While a blink is necessary for sight, a heartbeat is necessary for survival. This presentation shows the societal implications upon life and life quality brought by the invention of artificial hearts and contact lenses. Artificial hearts introduced the old medical concept of triage into a new societal context. Contact lenses introduced artificially perfected sight invisible to all but the wearer.

The first blood pump

The artificial heart has started and stopped over its one hundred and twenty year history, but feasibility of a self-contained apparatus could only be imagined with a workable blood pump. William W.L. Glenn, M.D. was “most fortunate” to work with William H. Sewell, Jr., M.D. to create a heart pump as a bypass: “I do not know when he first got the idea that he wanted to build an artificial heart. It is likely this was when he entered medical school and perceived a practical use for his mechanical skills. He told me that as a child he often played with an Erector set his father bought him” (Glenn, 1993).

The first blood pump cont'd

Sewell constructed a single bypass pump from household items and a children’s toy. Sewell and Glenn found the test dogs healthy after the pump test: “That it was possible to bypass one side of the heart with a mechanical pump for a prolonged period with survival of the animal and that the chamber of the right ventricle could be exposed long enough for deliberate performance of a cardiac operation under visual control had been demonstrated” (Glenn).

Legacy of the blood pump

1964 saw the first use of a nearly identical pump in an operation on a patient.

Modern versions of the centrifugal Bio-Pump invented by Harold Kletschka in 1975 are still sold and are in use for biventricular support in 2009 (Oransky, 2004).

Artificial heart valves

Development towards a True Artificial Heart (TAH) was incrementally iterative. Each new technology had a separate application to a specific problem.

The blood pump served to circulate blood, and the artificial heart valve served as a circulation gateway.

Hydraulic engineer

Albert Starr and the Edwards Development Laboratory developed the valve alongside financier M. Lowell Edwards: “background was in hydraulic engineering, and he designed many hydraulic debarking systems for the lumber industry. He had many patents, the most important of which was his fuel-injection system for rapidly climbing aircraft during World War II. [… ] His interests in fluid dynamics was now directed to the human circulation” (Starr, 2007).

Success of AHV

A whole kennel of dogs died in 1958 from the first valves, but when one survived, so the experiment survived.

In 1960, the second patient survived the surgery and lived a normal life for more than nine years afterwards.

Legacy of valve replacement

“Valve replacement became a frequent procedure, with a fall in operative morality from 50% to zero in the first six years” (Starr). By the 1990s, a tissue substitute replaced the synthetic valve materials and made valve repair surgeries an almost routine procedure. Valve replacement had a high success rate from initial surgeries.

The first TAH bridge to transplant

Development of a TAH was a more complex task with more complex equipment.

A 1969 surgery installed an internal TAH as a bridge to receipt of a heart transplant, but the patient died soon after from multiple organ failures (Smithsonian, 2009).

Complications

In 1991 and up to present day, complications are still present: “Short-term and long-term pnuematic and centrifugal unilateral and bilateral assist devices and total artificial hearts have complications of thrombosis, sepsis, bleeding, and hemolysis, and it is not entirely clear which will be the limiting factor in these devices” (NHLBI, 1991, p. 220).

Limitation factors on the TAH patient also exist, in the form of mobility and mortal longevity.

Development of TAH An energy source is required for every

assistive machinery or TAH. The 2001 AbioCor featured electrical conductivity from beneath the skin and reduces risk of sepsis infections, whereas pneumatic internal devices require a hole in the thoracic skin. 1974 ended propositions for nuclear powered devices (NHLBI, p. 207). Despite complications, breakthroughs came gradually, initiated by the first bridge to transplant in 1978, and continued by a fifty four hour bridge to transplant in 1981 (NHLBI, p. 208).

The first destination TAH

The Jarvik-7 implant into Barney Clark in 1982 was a left ventricular assist device (VAD), a stage of innovation in between a TAH and a Bio-Pump. Clark was already critically ill prior to surgery. Clark suffered from multiple organ complications suffered while in a hospital for 112 days (Sandeep, 2004). Until 1990, few TAHs were used, but VADs saw widespread use.

Major TAH deployment

“On July 2, 2001, the first fully contained artificial heart was implanted in a 58-year-old man at Jewish Hospital in Louisville, Kentucky” (Sandeep). The hydraulically powered Ambiocor device has been implanted in at least thirteen patients.

As of 31 October, 2009, “there have been more than 800 implants of the [SynCardia] Total Artificial Heart, accounting for more than 170 patient years of life on the device” (SynCardia, 2009). The SynCardia is not used in the U.S.

Intended usage

The devices are a destination, but not a substitute for a transplant.

TAHs give patients an average of six months and double life expectancy, enough time to get affairs in order.

Societal impacts

The primary use of VADs is as a bridge, which leaves the TAH with a selective, terminally ill group of patients.

Yet the selection of patients is limited by expense and complications. There are more eligible patients for TAHs than there are resources.

Not every patient is qualified for a VAD bridge to transplant. The result is triage. Society faces an old medical challenge, but one that is rendered inert in other areas.

Impact on innovation and perspective

Social acceptance and demand for TAHs led to research and development for other organs (Koford, 2004). The artificial kidney was invented, went through a triage period, and finally achieved social acclimation as a common, widely available piece of medical equipment.

While TAH and TAK are critical sustainers of life, survival has not yet taken priority over quality of life. The TAH may offer a momentary reprieve from death, but given a choice between survival and the quality of life offered by contact lenses, the importance of TAH takes precedence.

The first widely influential contact lenses

The history of contact lens idea conception goes back further than the 1936 use of polymethyl methacrylate (PMMA) and the 1888 glass lenses, but contact lenses did not start to see a societal impact until soft lenses were created in 1971: “Thus, PMMA haptics fom the late 1930s and then flat Tuohy and contour PMMA lenses dominated the contact lens field until hydrogel contact lenses became available in about 1971” (Bennett, 2005, p.4).

Innovations in lens materials

The soft hydrogel lenses were comfortable enough for daily wear up to thirty days, but made the eye swell overnight due to oxygen deprivation of the cornea.

As a result, by 1984, rigid-gas-permeable (RGP) contact lenses were still used more often than hydrogel lenses due to the higher oxygen and moisture levels in rigid lenses.

By 1991, soft silicone lenses had the highest gas transmission of the three types (Flattau, 1991, p. 8).

“Corneal oxygenation during the wear of rigid contact lenses occurs both by passage of oxygen through the lens material itself and by introduction of oxygen containing tears beneath the lens during blinking” (Patterson, 1999).

Adoption of contact lenses

The development and manufacture of contact lenses has always been a group effort. Silicone elastomers in 1981 and silicone hydrogel in 1998 were developed by large multinational corporations (Bennett, p.1).

Disposable lenses debuted in 1984 and were reinvented and commercialized by Johnson & Johnson in 1988 (Bennett, p. 9).

The disposable silicone hydrogel was inexpensive and comfortable enough to cement the contact lens as a replacement for glasses for an entire society: “nearly 35 million persons in the United States and 85 million or more worldwide wear contact lenses” (Bennett, p.10).

Societal impact of contact lenses

Contact lenses are plentiful and widely available. The societal impact of contact lenses is more than correction of vision.

Lenses do not break in the same way glasses do, thus are safer for sports and are more replaceable than glasses. Lenses give a complete field of view lacked by glasses. Normal corrective contact lenses do not obstruct the face as glasses do. Contact lenses invisibly raise quality of life.

Conclusion

Contact lenses show the elevation of quality of life that a medical and social invention should ideally accomplish. While the TAH is not the permanent correction that contact lenses are, it gives a form of life and a crucial iteration toward a curative solution. The future of the heart beat will be determined by the creative visions of inventors.

References 1 of 4

Bennett, E.S., Weissman, B.A. (2005). Clinical contact lens practice.Philadelphia, PA: Lippincott Williams & Wilkins. Retrieved 31 October, 2009 from http://bit.ly/1bvXaH

Flattau, P.E. (ed.). (1991). Considerations in contact lens use under adverse conditions: proceedings of a symposium. , D.C.: National Academy Press. Retrieved 31 October, 2009 from http://bit.ly/1VDoNd

Glenn, W.W.L. (Winter 1993). Sewell’s pump. The Guthrie Journal, 1(63). Whitney Museum. Retrieved 30 October, 2009 from http://bit.ly/3lvsF

References 2 of 4

Koford, J.K. (2004). High technology in the healing arena: A history of the artificial kidney, 1913--1972.Ph.D. dissertation. Utah: The University of Utah. Retrieved October 31, 2009, from ProQuest Dissertations & Theses: Full Text.

Sandeep Jauhar.  (2004). The Artificial Heart. Boston, MA: The New England Journal of Medicine, 350(6), 542-4.  Retrieved October 31, 2009, from Research Library Core.

NHLBI, Hogness, J.R., VanAntwerp, M. (1991). The artificial heart: prototypes, policies, and patients. Washington, D.C.: National Academy Press. Retrieved 30 October, 2009 from http://bit.ly/UcayK

References 3 of 4

Oransky, I. (8 May, 2004). Obituary: Harold Kletschka.London, UK: The Lancet. Retrieved 8 October, 2009 from http://bit.ly/3ySJ8w

Patterson, H.A. (1999). The effects of rigid contact lens center thickness, material transmissibility, and blinking on oxygen shortfall of the human cornea. , OH: Ohio State University Press. Retrieved 31 October, 2009 from http://rave.ohiolink.edu/etdc/view?acc_num=osu1159556692

Smithsonian. (2009). Treasures of American history: human machines.Washington, D.C.: Smithsonian Institution National Museum of American History Kenneth E. Behring Center. Retrieved October 30, 2009 from http://bit.ly/3WrLrK

References 4 of 4

Starr, A. (2007). The artificial heart valve.Lasker Foundation. Retrieved 30 October, 2009 from http://www.laskerfoundation.org/awards/pdf/2007_c_starr.pdf

SynCardia Systems, Inc. (July 2009). 800th implant of world's only approved total artificial heart performed by heart and diabetes center NRW in Hospital Business Week (135).Retrieved from http://bit.ly/12bBH3