ASAIO GOLD

The 25 Landmark ‘Milestone’ Papers Published by ASAIO

1955-2003

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Cardiopulmonary Bypass for Cardiac Surgery

1. Gibbon, JH Jr, "Artificial Heart-Lung Machines: Chairman's Address," TASAIO 1:58-62 1955.

Commentary: It was fitting that Dr. John Gibbon, Jr. was not only persuaded to become a member of the newly formed ASAIO but that he chair a session on heart-lung machines at the first meeting. Twelve papers, out of 28 total on the program that year, dealt with blood pumps and gas exchange. Dr. Gibbon took the moderator’s prerogative to add some perspective to the proceedings by reviewing his considerable personal experience leading up to the first successful clinical use of a heart-lung machine for closure of an atrial septal defect. The case had been performed just two years earlier, and he expressed justifiable pride in having accomplished this momentous feat by saying, “It is nice to have this successful operation on record.”

He also offered his assessment of the current state of the art with artificial hearts and lungs as compared to other methods used when performing open-heart surgery in the 1950s. He predicted that heart-lung machines would enable the new field of cardiac surgery to develop with less risk than using either hypothermia or cross-circulation. He talked about problems in obtaining accurate diagnoses and of poorly understood results of surgical correction of some congenital lesions. He alluded to patients of his who did not survive open-heart surgery after the one successful case, and even suggested that a heart-lung machine might not be necessary for closure of a simple atrial septal defect. Expanding on his review of the current status of the apparatus, he qualified it as being “…a perfectly adequate method of gas exchange without any danger of air embolism,” and went on to say that the problem of handling coronary venous return had been solved and that blood pH was automatically controlled.

He mentioned younger workers several times in his paper and said he felt like an old man (he was just 51 years old). He believed the new investigators within ASAIO’s ranks would carry on with refinements in the technology and “make significant contributions to this field in the future.” In hindsight, his prediction was spectacularly prescient. – Mark Kurusz, CCP

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2. Clark LC Jr: Monitor and control of blood and tissue oxygenation. TASAIO 2:41-45, 1956.

Commentary: Dr. Leland C. Clark, Jr. is the developer of the Clark oxygen electrode and is considered as the father of the biosensor concept.  This development has served as the standard in the field.  In this paper he discribes inprovement in the use of his electrode for the continuous monitoring of oxygen tension in blood in a bubble-defoam device for blood oxygenation.  The basic principle of his electode employs the polarographic measurement of oxygen using a barrier (oxygen permeable membrane) that does not require tissue or blood contact with the electrode's cathode or anode.

He pioneered woork in the development of oxygenating systems in the early 1950's with Frank Gollan and Vishwa Gupta as well as chronic monitoring of oxygen in perfusion. In an 1962 address to the New York Academy of Sciences he described how to make electrochemical sensors (pH,polarographic, potentiometric or conductometric ) more intelligent by adding enzyme tranducers as membrane enclosed sandwiches.  He coined the term enzyme electrode.  Clark's ideas became a commercial reality with a successful re-launch of the Yellow Springs Instrument Company (Ohio) glucose analyzer based on amperometric detection of hydrogen peroxide.  This was the first of many biosensor - based laboratory analyzers to be built by companies around the world. -- Paul S. Malchesky, D.Eng.

Commentary: Two issues were paramount for those performing extracorporeal circulation in the 1950s: first, the need for reliable monitors of adequacy of perfusion and, second, simplicity of device design. In this regard, the Clark electrode for measurement of oxygen tension in either flowing blood or organs fulfilled these two goals. Dr. Clark’s rationale for developing the small glass and polyethylene membrane probe was based on his belief that, “…the more information we can obtain concerning the physiological status of the patient or animal, the more intelligently the [heart-lung machine] can be designed and controlled.”

He discussed the optimum size of bubbles for oxygenation and carbon dioxide removal for a bubble or “dispersion”-type oxygenator, which he and colleagues, Frank Gollan and Vishwa Gupta, described in 1950. Helmsworth, Clark and others subsequently used it clinically in 1952 on a 45-year-old man with fibrotic lungs and cor pulmonale. The patient’s symptoms improved during the 75-minute period of partial respiratory support. One year later, the same group used the apparatus for cardiac surgery on a 4-year-old boy with a preoperative diagnosis of atrial septal defect. Despite large volumes of coronary venous blood that led to hemodynamic problems, the patient was weaned after 33 minutes of extracorporeal support. He awoke, was extubated and responded, but died 16 hours after surgery from renal failure and brain damage, which was attributed to prolonged hypotension during perfusion. The congenital lesion was also found at surgery to be a partial arteriovenous canal.

Despite these early disappointments, the heart-lung machine functioned “perfectly”, due in part to use of the Clark electrode. Today, inline sensors, several versions improved over that first described by Dr. Clark, are indispensable tools to monitor blood gases and safely manage perfusion. In the discussion following this paper, Dr. Clark noted that the response time for the probe and recorder to equilibrate was a matter of 3-4 seconds and that oxygen tension values were continuously displayed. Another discussant called the Clark electrode a “fundamental contribution” in studying organ physiology during acute or chronic experiments. – Mark Kurusz, CCP

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