Blood Chamber Research Articles

A perfusion system for preparing the victim and the ischemic limb for reimplantation

We have developed and tested an original perfusion system for rapid and effect ive simultaneous preparation of the victim and the traumatically amputated limb, after a long period of ischemia, for reimplantation. The extracorporeal circuit of the circulatory system (Fig. 1) includes the main drainage channels 3 and 6, reservoirs for holding the perfusion fluid 7 and 14, peristaltic (roller) pumps 8 and 15, a column 9 containing the hemosorbent, a low-output membrane oxygenator with heat exchanger (LMO-HE) (International Standard) 10, the isolated donor's spleen 11, an ultraviolet source (UVS) 12 for irradiating the blood, the rotor of the RK-0.5 blood fractionator 13, and transducers for measuring perfusion pressure 16 and temperature 17 and 18. During development of the system we initially assumed that the hemosorbent and living isolated hepatocytes can temporarily perform the detoxicating function of the liver. Besides this function, hepatocytes utilize toxic substrates of lipoprotein complexes, which are essential for the restoration of disturbed metabolic processes (aerobic oxidation, etc.) in cells. The action of the donor's spleen, UV irradiation, the AUVM-Dnepr -MN-1 activated carbon fiber adsorbent, and of dioxidine was aimed at neutralizing the damaging action of microorganisms and leading to their elimination. In addition, the UVS stimulates processes of energy metabolism and oxidative phosphorylation, as well as transmembrane mass exchange in isolated hepatocytes, and this must unquestionably make the working of the whole system more efficient. The perfusion medium was obtained by diluting whole blood by one-third of its volume with native plasma, and also by adding heparin in a dose of 5000 U and 30 mi of a 1% solution of dioxidine for every 400 ml of fluid. The final hematoerit reading of the perfusion fluid was 28-32%. The extracorporeal circulation was filled with perfusion fluid, the volume of which corresponded to the mass of the amputated limb (1:1). The temperature of the perfusion fluid entering the main artery was 37"C, the perfusion pressure was 70-80 mm Hg, and the volume velocity of regional perfusion was 40-60 ml/(min.kg). The pO 2 of the perfusion fluid entering the arterial system of the amputated limb fluctuated from 160 to 300 mm Hg. The duration of isolated regional perfusion of the amputated limb and of the limb stump below the tourniquet was 1 h. The AUVM-Dnepr -MN-I activated carbon-f iber adsorbent, soaked with 1% dioxidine solution, was applied to the infected wound surface of the amputated limb. The extracorporeal system (Fig. 1) works in the following way. Perfusion fluid draining from the veins of the limb and stump enters the first reservoir 7, which may be equipped with a volume self-regulator, and it is pumped from the reservoir by the pump 8, through the column 9, which has a volume of 100-250 ml, and which is filled with hemosorbent ( S K N I K or SKN-2K) . Next, at the rate of 30-40 ml/min the perfusion fluid passes through the blood chamber of the LMO-HE (International Standard) chamber 10, where it is saturated with oxygen and heated. The perfusion fluid then passes through the regional vascular bed of the isolated donor's spleen 11 and, passing through the UV source 12, it enters the rotor 13 of the RK-0.5 blood fractionator, containing 100-350 ml of a dense suspension of hepatoeytes. The speed of rotation of the rotor is 600-800 rpm. The design of the RK-0.5 rotor is intended to ensure direct contact between the flowing perfusion fluid and hepatocytes. After the rotor the perfusion fluid drains into the second reservoir 14, which may be equipped likewise with a servo-operated volume regulator. From the reservoir the perfusion fluid is pumped by the roller pump 15 into the arteries of the isolated limb and stump. Isolated living xenogeneic hepatocytes were isolated by a combined enzymic-mechanical method [1, 2]. During regional perfusion of the limb, a dense suspension of hepatocytes containing 2 x 108 cells in 10 mi was used. Hepatocytes kept in the extracorporeal circuit by centrifugal force or by capsules of semipermeable membrane functioned actively on direct contact with the perfusion fluid throughout the period of perfusion (results of electron-

A unique left-right flow imbalance compensation scheme for an implantable total artificial heart.

A new method has been developed for accommodating the difference between pulmonary and arterial flows in a totally implantable, hydraulically actuated total artificial heart (TAH). The left and right sides are alternately pumped, with concurrent filling of one pump and ejection from the other. A small hydraulic fluid chamber is used to compensate for the higher left sided flow. This chamber is incorporated into the left inflow of the TAH, with the flexing bladder in contact with atrial blood, and the hydraulic fluid communicates with the right sided hydraulic chamber. The volume of hydraulic fluid that enters and exits the latter chamber constitutes a corresponding reduction in the right sided blood chamber stroke volume. Placement of this compensation chamber in the left side inflow provides a negative feedback of the right sided flow, based on the left atrial pressure (LAP). Higher LAP (indicating too much right sided flow) leads to higher fluid flow to and from the compensation chamber and a lower right sided blood flow and vice versa. The hydraulic flow resistance can be preadjusted to yield a 15% flow difference at an LAP of 15 mmHg.

A pulsatile pump for cardiopulmonary bypass and its clinical use.

A pulsatile pump driven by a coil spring, which was designed and constructed by us, is described in this report. It consists of two main parts, a disposable blood chamber and a driving section. The blood chamber has two leaflet valves and a piston, which is covered with two bellofram rolling diaphragms and moves into the housing to draw in and eject the blood. The driving section consists of three cams, an electric motor and a coil spring. The ejection force is wholly produced by the compressed coil spring and is transmitted to the piston in the blood chamber by a rod. This pump allows the ejection pressure, the beat rates, and the stroke volume all to be changed independently. The performance of the pump was tested by using a circulation model where the beat rate was adjusted from 30 to 250 bpm. The output subsequently increased from 0.8 l/min to 5.7 l/min and the stroke volume, from 20.4 ml to 36.7 ml. This new pump has been used for clinical cardiopulmonary bypasses in 24 patients of open heart surgery and the pressure traces during perfusion resembled those of the patients' own hearts.

Use of an ellipsoid artificial heart.

Experiments with the Poisk model of an ellipsoid artificial heart are reported. With a modified model of the diaphragm type made from polyurethane, calves survived for a mean of 55 days, with a maximum survival of 3 months. With adequate anticoagulation therapy, no thrombogenesis was observed in the blood chamber (except for the inlet valves); a low level of plasma hemolysis was observed postoperatively. Good correlation was demonstrated between the stroke volume and left and right atrial pressures. Changes in the blood coagulation indices are reported. Implantation of a clinical variant of this prosthesis into human cadavers demonstrated no difficulties in placing the heart in the pericardial cavity. Developmental efforts are continuing.

Paracorporeal assistance system for restoring cardiac activity.

Two series of experiments were conducted to assess the potential of artificial ventricular bypass in restoring cardiac activity. One series evaluated use of a paracorporeal left ventricle in 17 calves; the other evaluated biventricular bypass in 11 calves. Module pumps with a seamless blood chamber of polyurethane were used. Pump function and system parameters were controlled by a Sinus VK-2 control system. Assisted perfusion began with the induction of ventricular fibrillation. The experiments showed that left ventricular bypass was an effective method for long-term maintenance of the hemodynamics during fibrillation, leading to certain biochemical corrections and restored electrical activity and myocardial contractile function. The hemodynamic state was maintained at a higher level with biventricular bypass and was accompanied by a greater percentage of restored myocardial function. Uneven restoration of contractile activity in the left and right ventricles points to the need for adequate support of both ventricles.

Development of a seamless blood chamber assist pump

Development of a seamless blood chamber assist pump

A Three-dimensional Boundary ElementModel Of The Electric Field From ImplantableDefibrillators

The delivery of high energy shocks from implantable defibrillators is largely influenced by the design and configuration of the delivery electrodes. To optimise electrode design and placement, a 3-D boundary element model of the electric field from implantable defibrillators was developed. The model used approximately 3500 constant quadrilateral elements, constructed from MRI scans, and consisted of eight isotropic regions that represented the chest, heart, left and right blood chambers and vessels, lungs, spine and sternum. Additional regions represented epicardial, endocardial and subcutaneous electrodes. The governing Laplace equation was solved to find potentials and gradients throughout the thorax. This paper discusses the implementation of the model and presents results that show differences in the electric field between an endocardial and epicardial electrode configuration.

Cellular membrane formation by plasmatocytes of diapausing Cecropia pupae

The early phase of wound healing in diapausing Hyalophora cecropia pupae is dominated by the formation of an acellular membrane by plasmatocytes. Phase contrast microscopic observations of blood from unwounded pupae reveal few circulating haemocytes, approximately half of which are plasmatocytes of varying morphology. In the days following injury both the absolute and relative number of plasmatocytes increase. The initial increase in cell number is not attributable to mitosis because no mitotic figures are seen until 18–24 hr after wounding, whereas substantial increases in cell number are observed by this time. A relative increase in large fusiform plasmatocytes suggests instead that the initial cellular response to injury is the release of haemocytes from depots within the insect. Subsequently, mitoses of haemocytes, particularly plasmatocytes, become rather frequent, and further increases in cell number appear to result from these mitoses. Time lapse sequences of wound healing were photographed with phase optics through the optically flat surfaces of a plastic chamber which connected the haemocoeles of two pupae in telobiosis. As plasmatocytes touch the plastic surface of the chamber, they lose much of their heteromorphy. On these surfaces a cell typically flattens, produces a ruffled membrane, and migrates randomly over the plastic. As the population of attached haemocytes increases, movement of the individual cells is progressively restricted. A complete cellular sheet eventually covers the plastic surfaces. This cellular membrane is subsequently thickened by the deposition of additional plasmatocytes on the blood side. The cellular membrane then degenerates and tears free from the plastic. The broken membrane fragments are pulled into the wound areas by circulatory movements of the haemolymph and partially seal the pupae from the blood chambers. Wound closure is aided by the tendency of hyaline plasmatocytes to adhere to each other and to other cells and thereby to form large clumps of cells. These clumps attach to membrane fragments and form plugs that stop the flow of haemolymph into the blood chamber. Tracheae, accompanied by epithelial sheets, grow from the margins of the wound. The extending tracheal system aids in wound closure and is the means whereby a continuous epithelium is established across the injured area. Since hypodermal cells apparently do not undergo mitosis in the absence of ecdysone, and since only occasional hypodermal cells and a few tracheoblasts synthesize DNA in the absence of hormone, the ability of the cells of the tracheal system to migrate and produce an epithelial sheet assumes great importance for successful wound healing in diapausing pupae. Evidently the replacement of thinned-out epidermal cells as well as the secretion of a cuticle in the wound area is delayed until the hormonally mediated pupal-adult transformation.

慈大式人工腎臓の研究

In order to improve the dialysis efficiency of the Jikei Electro-Dialyzer, the author constructed a new type of electro-dialyzer with many dialysis chambers. This new apparatus consist of three blood chambers and two bath fluid chambers. Each of them is placed alternately and combined with bolt and nut. Then, all the chambers are set into an outer bath fluid chamber with an electric board. The blood chambers are thin in thickness and consist of many more chambers as compared with the D-Type blood chambers. Consequently a larger dialysing surface can be obtained without enlargement in scale. Each chambers is place three dimentionally against the electric field, in order to maintain the characteristic function of the electro-dialysis.The author carried out various in vitro experiments on the fundamental dialysing efficiency of the apparatus with three blood chambers, and for in vivo experiments the author used six nephrectomized dogs to study the practical dialysing efficiency of the apparatus. Six nephrectomized dogs were hemodialyzed for 2 hours respectively, and observation were made on the changes of B. U. N. and blood electrolyte value before and after hemodialysis. Among the six dogs, three were hemodialyzed after 24 hours and two after 48 hours following bilateral nephrectomy. One was hemodialyzed by using two blood chambers after 24 hours following bilateral nephrectomy.The results obtained in vitro experiments are summarized as follows.1) This apparatus has a larger dialysing area as compared with the D-Type Electro-Dialyzer without enlargement of its scale.2) It needs a larger amount of bath fluid than the D-Type Electro-Dialyzer during 2 hours hemodialysis (about 271)3) Limitation of blood flow is 170cc/min, and the suitable flow is 100-120cc/min.4) When the temperature of this apparatus chamber reaches 35-37°C, an electric current density similar to that of D-Type Electro-Dialyzer can be obtained.5) Series connection proved more satisfactory than the parallel method.6) The dialysing efficiency of nonelectrolyte and electrolyte substance was better than the D-Type Electro-Dialyzer.7) Furthermore, there is a possibility that this apparatus can remove the body fluid by ultrafiltration. Ultrafiltration is caused by a rise of inner pressure of the blood chamber.The experimental results of bilaterally nephrectomized dogs are as follows.1) Approximately 15mg/dl B. U. N. can be removed hourly.2) As to the corrective ability of blood electrolyte imbalance, especially hyperpotassemia which was observed all nephrectomized dogs, a return to normal level was found after 2 hours of hemodialysis.3) When two blood chambers are applied, the B. U. N. dialysis efficiency consisted in the capacity to remove 7mg/dl hourly.This new apparatus which has many adventages as an effective artificial kidney can be used clinically for the treatment of uremia.

On the Nature of the Cellular Elements present in Milk

That cellular elements are found normally in milk has been known for many years, but it is only comparatively recently that any importance from a public health point of view has been attached to their presence. These cellular elements being usually regarded as leucocytes or pus cells, it is natural that their occurrence in milk should be looked on as indicative of an inflammatory process in the udder of the cow or cows from which the milk was obtained. The first observers to make any attempt to arrive at the numbers of these cells in milk seem to be Stokes and Wegefarth (1) in 1897. Their method, however, was very crude, and is not suited for making a true enumeration. Stewart (2) and Slack (3) followed with a very similar method, except that special tubes were used for obtaining the deposit. This “smeared sediment method” as it is called, is, however, capable of great inexactitude. Later observers have, by the use of ordinary blood counters, made the counting of the cells in milk a scientific measurement of reasonable accuracy. To Doane and Buckley (4) belongs the credit for the first published use of such a method. Savage (5) however has made the process still more accurate by first diluting the milk before centrifugalisation, and also by counting all over the field of the blood chamber, two innovations which are of very great importance, as has been borne out by our investigations. Error is easily introduced if counting is confined to the ruled divisions of the counter. Recently, Trommsdorff 6 has used a methodbased on the measurement of the deposit obtained on rotation in agraduated tube, and this method, probably on account of its ease and speed, has found much favour in Germany. It has been severely criticised by several investigators, such as Schuppius 7 and one of us 8. Riihm 9 and some others believe that it is useful if used as a routine control method. We are of opinion that it might be used in such away as an “indicator,” but for the purposes of public health control it isquite hopeless.