A Self-contained, Disposable Oxygenator of Plastic Sheet for Intracardiac Surgery: Experimental Development and Clinical Application

Abstract

Since the first months of 1955 more than 200 patients at the University of Minnesota Hospitals have undergone direct-vision intracardiac surgery, utilizing a bubble oxygenator (DeWall, Warden, Read, Gott, Ziegler, Varco, and Lillehei, 1956;Lillehei, DeWall, Read, Warden, and Varco, 1956) in combination with a pump for supporting the systemic circulation during this interval when the heart and lungs are totally by-passed.During this period of clinical experience this pump-oxygenator has passed through several stages of evolution, each design being more simple than its predecessor. All models have been constructed of expendable polyvinyl tubing and have employed the same principles of a vertical mixing tube, an antifoam-coated debubbling chamber, and a helix settling chamber for the final elimination of all bubbles. Our clinical experience with these models has been most encouraging. In order to facilitate the widest application of these advantages of open heart surgery, experiments have continued with the object of providing an equally effective and inexpensive oxygenator which also would be expendable and adaptable to commercial manufacture in quantity. THE SHEET OXYGENATORUsing the same tested principles as mentioned above, an oxygenator (Figs. 1, 2, and 3) has been developed. It is constructed of two thin sheets of polyvinyl plastic, the desired channels and chambers being delineated by a heat seal of the plastic sheets.This oxygenator is a self-contained unit with an oxygen disperser, heat sealed in the lower end of the * National Heart trainee, U.S.P.H.S.

Perfusion in Britain: the early days

“…34 Clinically, in April 1956, he operated on a patient with a ruptured ventricular septum following a myocardial infarct, who lived for six weeks. During those six weeks he did five more cases, all of whom survived.…”

“…His initial oxygenator consisted of a stainless steel oxygenating chamber and spiral defoamer, but he changed to Gott's 'Baxter bag', a commercially produced single plastic sheet development of the DeWall oxygenator, the great advantage of which was its ease of assembly and disposal. 34 Clinically, in April 1956, he operated on a patient with a ruptured ventricular septum following a myocardial infarct, who lived for six weeks. During those six weeks he did five more cases, all of whom survived.…”

Performance of Baffled Bubble Blood Oxygenators

“…In the present case, the resistance to oxygen transfer is obviously in the blood phase, since the gas phase is almost pure oxygen. The volumetric coefficient of oxygen absorption into blood based on the difference in the oxygen concentrations in the blood phase, K'La, can be defined by the following equation: (1) where r,, is the oxygen absorption rate, QB is the blood flow rate, Vo is the volume of the oxygenating column, and C is the concentration of oxygen physically absorbed in the whole blood. The value of C can be determined from readings of the oxygen l-0 2 = QB (CA -Cv) = K'La Vo (C* -CA) analyzer, i.e., Poz, the solubilities of oxygen in the plasma and in the red cells as reported by Sendroy et ~2 .…”

The history of extracorporeal oxygenators*

“…This was because of their many advantages: they were highly efficient because of the large cumulative surface area of the oxygen bubbles; they had a simple design without moving parts other than the mechanical pumps that drove the circulation; the components of the circuit were easily sterilised and they were disposable [2,6,38,45]. Their popularity was cemented with the advent of single-use, relatively inexpensive, presterilised and prepacked plastic versions [2,[45][46][47][48]. A further advantage was that the priming volume required for these disposable devices was so small that a saline prime would often suffice without the addition of donor blood.…”