| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Ann Thorac Surg 2002;74:612-614
© 2002 The Society of Thoracic Surgeons
a Department of Cardiothoracic Surgery, Mount Sinai Medical Center, New York, New York, USA
* Address reprint requests to Dr Litwak, Department of Cardiothoracic Surgery, Mount Sinai Medical Center (Box 1028), One Gustave Levy Pl, New York, NY 10029-6574, USA
 |
Introduction |
|---|
 Top Introduction References |
|---|
The oxygenator investigation began at the Fels Research Institute for the Study of Human Development at Antioch College where Dr Clark, the chairman of the Department of Biochemistry, Gollan, and a research associate, Vishwa Gupta, devised and described an efficient bubble oxygenator [4–6]. Although the apparatus was slightly modified later [7], there were three essential features: a multi-perforated disc, a coalescence ("def oaming") chamber, and a combined bubble trap and oxygenated blood residence component (Figs. 1 and 2). Oxygen under pressure was dispersed through the porous disc into a venous blood column that instantly created arterialized foam. A key feature of the system was the capacity to efficiently coalesce the oxygenated foam by contact with glass beads that had been coated with DC Antifoam A, a methylpolysiloxane resin, which, only 2 years earlier, had been reported by the Dow Corning Laboratories to be both effective and innocuous [8]. The critical importance of DC Antifoam A in oxygenator performance was emphasized by Clark, Hooven, and Gollan:
[The gas dispersion] oxygenator is based upon the knowledge that a huge gas-liquid interface can be created in a relatively small volume by bubbling gas through the liquid. Its inherent difficulty is that of completely removing these bubbles... . Although many methods, such as continuous centrifugation or even filtration, may be devised to remove these bubbles, the simpler method of coalescence and trapping is used in the present apparatus. The availability of a nontoxic, nearly water-insoluble polymethylsiloxane "defoaming" compound has been utilized as the surface for this coalescence [7]... .
View larger version (35K):
[in this window]
[in a new window]
Fig 1. Design of bubble oxygenator (Reprinted from Clark LC, et al, Proc Soc Exp Biol Med; 1950;74:268–71 [5], with permission).
View larger version (167K):
[in this window]
[in a new window]
Fig 2. Clark (on left), Gollan (on right), and Gupta (right arm) conducting early bubble oxygenator experiment (circa 1949 to 1950) at Fels Institute.
It is pertinent that an earlier attempt to oxygenate blood by bubbling the gas into venous blood had been made by von Schroder [9] in 1882 but foaming was a major impediment. Concerning this effort, Gollan commented "Schroder did not have an efficient bubble oxygenator but he had a very good idea" [10]. Seventy years later, with the availability of an effective means of dealing with the foaming problem, clinical use of a bubble-oxygenator in open cardiac operations could be envisaged. Indeed, Helmsworth and colleagues [11] reported in 1953 use of the equipment in closure of a ventricular septal defect in a 4-year-old child who unfortunately succumbed after operation. But the potential was clearly apparent. It was the fabrication of a simple, disposable bubble-oxygenator system several years later by Richard DeWall and colleagues [12] that made possible the world-renowned open cardiac surgical program led by C. Walton Lillehei at the University of Minnesota.
It is of interest that a young C. Walton Lillehei had written Gollan in 1951 concerning the need for a pump-oxygenator and solicited the assistance of the Fels investigator:
January 22, 1951Dear Dr. Gollan:
Dr R. L. Varco and myself are particularly interested in heart surgery and have been performing most of that type of surgery being done at the University Hospitals. In the course of these experiences, we have come to appreciate the great need for [a] simple pump-oxygenator apparatus. For many of the intracardiac operations we would not need at the most more than 10 to 12 minutes. in a relatively dry field. Therefore, the apparatus does not need to be unduly complicated.
I have had occasion several times recently to discuss these thoughts with Dr Visscher [Professor and Chairman, Department of Physiology] and he has told me of the fine progress that you people have made in this field, and he suggested that I communicate with you.
I would greatly appreciate receiving any reprints, pictures or technical information that would enable us to build an apparatus modeled after yours, or by any chance, are any of your latest pump-oxygenators available for purchase?
Finally, would you or anyone in your group be interested, provided the necessary arrangements can be made in coming here to Minneapolis with your pump-oxygenator with the idea of giving it a clinical trial. We have several patients here who are otherwise doomed to an early death unless such an approach can be made for repair of their intracardiac defects.
I shall await your comments on these suggestions with interest.
Yours Sincerely,
C. W. Lillehei, MD
CWL:KRL
Parenthetically, the "secretary" who executed the letter for C. Walton Lillehei was a nurse—Kaye R. Lillehei! Unfortunately, a recent search made by her of C. Walton Lillehei’s files failed to reveal any correspondence from Gollan (personal communication). That there must have been prompt and presumably continuing communication between the two is attested by the known contact which DeWall subsequently had with Gollan (personal communication).
Appreciating the important studies of Bigelow and colleagues [13, 14], who documented the linear decrease in oxygen consumption in surface-cooled hypothermic animals, Gollan reasoned that metabolic stability under these conditions could be readily provided with substantially lower ECC flow rates. He and his colleagues undertook a series of investigations using a bubble-oxygenator and what proved to be a key technical advance: a heat exchange device that was incorporated in the ECC unit. In a report published in 1952, they described their approach:
In [prior] experimental investigations on hypothermia, the body temperature of animals has been lowered by immersion in cold water, covering with ice packs, contact with refrigerated coils or exposure to cold air. In the present study, a method is described by which the animals’ blood can be cooled or warmed while it circulates through an extracorporeal circuit... . By inserting a silver-tube coil into the venous part of the extracorporeal circuit the temperature of the circulating blood could be rapidly altered by immersing the coil in stirred ice water or in water of about 45°C [15].
This was the first of a number of studies in which it was documented that low flow ECC and cooling with an integral heat exchanger could efficiently establish conditions of profound hypothermia and rewarming (Fig 3) with survival [16, 17]. Using this methodology, Gollan and colleagues continued to investigate how low a reduction in temperature could be achieved with survival of the animal. Remarkably, survival was shown to be possible at both 0°C [18] and 1.5°C [19]. Although conclusive biophysical data did not exist at that time, one can discern from Gollan’s 1955 publication [19] his hypothesis that the combination of profound levels of hypothermia and low ECC flow rates in high or normal hematocrit circumstances would significantly increase blood viscosity. This hypothesis led him to prime the ECC apparatus used in these survival experiments with Ringer’s solution, a hemodilution approach that is virtually routinely used today in priming pump-oxygenators. Indeed, much of the technical and conceptual approaches developed by Clark, Gollan, and colleagues so many years ago is being used today in the operative management of complex cardiac and aortic pathology.
|
It is my hope that all those who attack the monumental problem of heart substitutes ... may see their work converted into means to relieve human suffering, because we live under the unforgettable command [of Horace Mann, Retired president of Antioch College in commencement address at that institution, 1859]: Be ashamed to die until you have won some victory for humanity.
|
References |
|---|
|
TopIntroductionReferences |
|---|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ANN THORAC SURG | ASIAN CARDIOVASC THORAC ANN | EUR J CARDIOTHORAC SURG |
| J THORAC CARDIOVASC SURG | ICVTS | ALL CTSNet JOURNALS |
