IONEX was applied as heparin adsorbent. IONEX was aimed to remove heparin from blood in blood perfused artificial organs before the blood is retransfused to the patient. In in vitro studies, whole blood taken from dogs was added to 5U/ml of heparin. It was introduced into a small column containing 0.9g of IONEX at various blood flow rates (0.8, 1.6 and 3.2ml/min). According to the results, a possible explanation was gained that the heparin distributed in the blood cells was passed on gradually into the plasma and so was not adsorbed at the faster flow rates. In ex vivo studies, the 5 systemically heparinized dogs (500U/kg) were treated with IONEX columns (containing 35-40g) by direct hemoperfusion (DHP). the concentration of heparin was significantly reduced with IONEX from 15 to 60 minutes after the start of DHP.

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It is well known that hemolysis by extracorporeal circulation (ECC) is a major cause of renal failure after open heart surgery. The purpose of this study is to investigate the effects of administration of haptoglobin (Hp) during ECC. The patients were divided into two groups: Group I 5 patients underwent open heart surgery: Group II 5 patients underwent open heart surgery added 4000 IU of Hp to a priming solution. The serum level of total Hp was elevated in group II during bypass. but reduced at the first day in both groups. The level of total Hb was elevated in both groups during bypass, and reduced at the first day within normal limits. Free serum Hb was found in group I at 30min after start bypass and increased during bypass and urinary Hb was also found. However, in group II free Hb was not found during and after bypass. Urinary NAG and alpha 1M levels in group I were significantly higher than those in group II. The administration of Hp during ECC prevents the increment of serum free Hb and is effective for protection of renal function.

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The Complement activation pathway during cardiopulmonary bypass (CPB) and transpulmonary leukosequestration were investigated in 13 adult patients with open-heart surgery. The initiation of CPB rapidly activated the complement system presumably through the classical pathway, in which acute leukocytopenia accompanied with continuous leukosequestration in the lung. The MDA levels during CPB showed a significant biphasic increasel giving the peaks 30 minutes after the commencement of CPB and reperfusion. There was no statistically significant relationship between leukosequestration and MDA production in the lung. However the increased MDA levels of the left atrial blood following reperfusion might be indicative of the damage to the endothelial cells of the lung vessels, owing to oxygen free radicals derived from the activated neutrophils.

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In order to estimate the liver ischemia during cardiopulmonary bypass (CPB), we measured Keton Body Ratio (KBR) before, during and after CPB. KBR was significantly decreased during aortic clamp. Four of seven patients (56%) who showed the lowest KBR≤0.35 developed postoperative liver dysfunction (GPT≥100) while patients who showed the lowest KBR>0.35 didn t develop. In conclusion, KBR can be an useful predictive indicator of postoperative liver dysfunction in patients after CPB.

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Continuous monitoring of blood glucose concentration was compared with intermittent sampling in 15 non-diabetic adult patients undergoing open heart surgery with cardiopulmorary bypass using priming fluids free of glucose (group C) or with glucose (group G). Blood glucose concentration decreased immediatery on the institution of CPB, after several minutes increased and maintained the same level in group C. In group G, the blood concentration increased immediatery on the instition of CPB, and maintained that high concentration level or gradually decreased. Increase of flood glucoss contration always associated with enfusion of glucose contained fluids.

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IN 14 patients having cardiac surgery, samples of collected shed mediastinal blood (SMB) were hematologically examined and were defined the coagulation system. SMB were studied two to four hours after operation in six patients (Group A) and 17 to 20 hours after operation in eight patients (Group B). No bacterial contaminations were seen in all of SMB collected from Group B. It contained sufficient levels of hemoglobin and serum protein in both groups. It contained normal level of platelets in those groups, while the status of coagulation system was impaired and it demonstrated defibrinogenation in the pericardial cavity without anticoagulants. In this study, autotransfusion of SMB seemed to be possible. We suggest that when the postoperative autotransfusion is applied in addition to preoperative autologous blood collection and operative autotransfusion, the indication of cardiac operation with autologous blood seems to increase and reduce bank blood requirement in case of chest reopen after operation.

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An automatically controled recording sytem was designed as a previous step for an automatically controled extracorporeal bypass circulation (ECC) system. This sytem was practically used in eighteen cases of open-heart surgery from March '87. to October '87. This system seemed to be very useful to ameliolate reliability on data sampling and recording, and to enable the perfusionist to concentrate on manipulation of ECC. On besides, by using specially developed linkage software, we can translate these data to the popular multifunctional application (Lotus 1-2-3), so the data analysis became much more easier. We are now developing the second version of this system as a ECC guiding system including some safety driving criterea and emergency reactionary function.

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The centrifugal pump (Bio Pump) have been widely used in many bypass circuits, because of its advantages of low hemolysis, protect of platelet and duarability of long term uses, in comparison with the roller pump. We evaluated new Bio Pump (model BP 80) which had lower priming volume than usual type (model 600), undergoing two-hour-cardiopulmonary bypass with ten mongrel dogs. The results were obtained as follows, no significant differences in hemodynamics, platelet count, hemolysis and prostaglandins between BP 80 and model 600. So this study suggested that LVAD and EGMO would be more useful by introduce of the new Bio Pump.

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We have been developing a pulsatile roller pump for infant's cardio-pulmonary bypass. The pump has following feathers: (1) a specially designed head-casing for improving output pressure waveform, (2) micro-processor controlled servo motor system for both precise flow control and high pumping rate (60-240[bpm]), (3) micro-processor aided operational-guide. The reliability of the pump was proved by 12 clinical cases (2 mo-7 yr). The pump produced pulsatile pressure waveform satisfactorily while the clinical experiences.

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Flows in the tube gap occluded by roller were analized by two-dimensional viscous theory. The results shows that there exists the optimum gap clearance in which the shear stress becomes minimum. This clearance corresponds to the well-known optimum occlusion gap. A profile of head casing, in which the change rate of displacement volume to roller rotation angle becomes much smaller than that of the conventional U-type, is proposed in order to suppress the pressure fluctuation in the tube. The pressure and flow rate were measured at the inlet, outlet and intermediate positions of roller pump compared between the U-type and the improved type. The fluctuations proved to be reduced for the improved type. The larger inner diameter of the tube, equivalent to the low rotational speed under the same flow rate, is efficient in suppressing the fluctuations. In the hemolysis test circuit for centrifugal pump, if the throttle ressistance is replaced by the inverse roller pump with the optimum gap, the shear stress in the gap becomes almost null.

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Availability of the regenerative pump as a blood pump for heart lung machine was evaluated through in vitro tests using a newly designed prototype pump. Dimensions of the impeller and the flow passage of the pump were determined so as to obtain the maximum pump efficiency at the design point; outlet pressure: 400mmHg, outflow rate: 81/min. Clearances between the impeller disk and the casing were varied and the influence of the clearance on the pump characteristics, flow pattern in the pump and hemolysis was evaluated. It was demonstrated that this prototype pump could attain the design point at a low pump speed (less than 2000rpm) and occurrence of hemolysis by the pump was relatively low and would be reduced in the clinicaly acceptable range by improving the pump structure and making the blood-contacting surface of the pump smoother.

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The purpose of this study is to examine the ability of the arterial line membrane oxygenator to preserve a pulse flow waveform. The inlet peak pressure was changed from 240mmHg to 510mmHg accompanied by the palsatile blood flows 2.0 to 4.0L/min. The loss of energy across the membrane oxygenator was abut 100mmHg, but the ideal physiologic arterial pressure waveform was obtained with the M-2000 membrane oxygenator. It was considered that effectire pulsatile extracorporeal circulation, as well as in cases of bubble oxygenator, could be achieved by using palsatile roller pump.

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Study was carried on cardiopulmonary bypass (CPB) without donor blood. Cellulose acetate (CA, 1.3m²) and Polypropylene (PP, 1.0m²) hemoconcentrator were used during and after CPB. PP showed lower proteinemia during and after CPB compared with CA (PP 4.2±0.8g/dl, CA 5.6±0.7g/dl at 90min of CPB). However, we never experienced disadvantages of low proteinemia. After CPB, the value of total bilirubin was lower in PP. PP might be beneficial for CPB instead of protein loss.

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In a case of recirculation (rec.) of blood priming for cardiopulmonary bypass (CPB) with a large quantity of alkalizing agents, a blood mass was formed on the surface of membrane oxygenator. Echinocytes, were found on the surface of the membrane through electromicroscope. Researching echinocyte formation, experiments were performed with 7%NaHCO3 and fresh, stored or remained circit blood after CPB. When PH was above 8.625, under 3.0mmHg of PCO2 and above +6.3 of Base Ex., blood mass were created without fresh blood. ATP values (nmoles/ml) in RBC at before and after rec. were showed 1811-845 in fresh glood and 995-654 in stored blood. Deformability index of RBC after rec. showed 56.7% of before rec. It was suggested blood mass formation was caused by echinocyte formation due to alkalosis.

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From July, 1984, to June, 1987, 16 infants weighing under 6kg were operated upon for congenital heart disease in our three inst tutes using newerly developed infantile heart lung machine (MSH, Senko Co., Tokyo) with membrane oxygenator (Capiox II, Terumo Co., Tokyo). Upon using them, priming volune was as low as 666±74ml (mean±SD). Oxygenation capacity was excellent with PaO₂ 493.5±132.0mmHg in cooling and 403±124.5mmHg in rewarming. PaCO₂ value was 35.9±8.2mmHg during cooling, however, it decreased below normal range of 23.8±5.7mmHg during rewarming. Platelet count was reduced to 11.1±5.1×10³/mm³ at the first postoperative day. Upon arrival to ICU, A-aDO₂ was high value of 508±113mmHg or of not satisfactory. We feel that it needs more improvement of ECC with other factors for open heart surgery in small infants accordingly to the clinical results.

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Non haemic cardioplumonary bypass is profitable, but in case of extreme hemodilution, is against a living body. While in operative and postoperative immune responses with car dioplumonary bypass (CPB) is specific-Now we investigated inoperative and and postoperative immune response of non-haemic CPB with new Sara membanouse oxgenator (SMO) which total priming volume is 1500ml-GroupI and compared with those of hemic CPB with oxgenator as before-GroupII. Result (1) There was no significant difference of in operative and postoperative immune responses betwen two Groups. (2) In CPB, the ratio of NK-cell to Lymphocytes in GroupII is higher than one in Group I. The ratio of T-cell to lymphocytes in Group I is higher bran in GroupII. Thease finding in GroupII presumably indicate that Increase of NK-cell, nonspecific immune response matter, makes relative dicrase of T-cell in lymphocytes. So GroupI in CPB will be preferable for a living body. (3) SMO with non-haemic CPB can start without extreme hemodilution will be preferable for a living.

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Hollow fiber oxygenator “MAXIMA” is extracapillary blood flow type, and charactaristic of minor pressure drop. Effective pulsatile extracorporeal circulation was derived by trans-lung pulsatile perfusion. This oxygenator had excellent capacity of gas exchange under pulsatile perfusion as well as that under continuous perfusion. Δplasma free Hgb was heigher than that of continuous perfusion. Administration of Haptoglobin could reduce hemoglobinuria.

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Clinical study of extracapillary blood flow type “Sarns” hollow fiber membrane oxygenator, and campard with Capiox II Sarns 16310 membrane oxygenator (group-C) which was extracapillary blood flow and low priming volume type used for open heart surgery in 22 adult patients, and was compared with intracapillary blood flow type Capiox II 43 (group-C) in 14 patients. The following vesults were obtained. The priming volume of group-S was remarkably decreased (P<0.05) than that of group-C. The amount of bank blood for group-S tended to be less than that for group-C. When the Sarns oxygenator is used, the cases with clear water priming for ECC in creases. In group-S O₂ transfer was better than that in group C and both PaO₂ and PaCO₂ were easily changed only by O₂ flow control. In group-S showed the bubble in oxygenator removed better than the other. It yield fewer micro-bubble during ECC and was easily operated. This study indicates that the Sarns oxygenator is suitable for clinical application.

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SMO was compared with COBE membrane oxygenator (CML) on 15 patients. SMO incorporates an integral heat exchanger and microporous, polypropylene hollow fiber membrane oxygenator. Though the effective gas exchange surface area of 1.8m² was small, SMO showed good oxygen and carbon dioxide transfer rates. SMO was useful in platelet reserve and red blood cell protection, too. In open heart surgery, the amount of blood transfusion is usually so much that serious post-transfusional troubles such as hepatitis often occur. Recently open heart surgery without blood transfusion is practiced in some hospitals. In such as situation, the low priming volume of only 320ml of SMO seems to be useful to reduce the amount of blood transfusion and to practice open heart surgery without blood transfusion.

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We have applied these two newly developed extracapillary blood flow type hollow fiber oxygenator (MAXIMA and SARNS). Both oxygenators had excellent gas transfer capability during the whole phase of cardiopulmonary bypass. Total priming volume including circuit was 1800ml in MAXIMA, 1500ml in SARNS respectively. So the use of SARNS had more advantage for the non-hemic primed extracorporeal circulation. The adverse effect on blood component such as hemolysis was observed especially in SARNS. It seemed to be due to high blood side pressure drop in Sarns. Both oxygenators, characteristic in lower priming volume provides suitability for non-hemic primed extracorporeal circulation.

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The present study elucidates gas transport in outside and inside blood flow oxygenators from the standpoint of boundary layer resistance. Overall gas transfer resistance was calculated, and the rate-determining step was determined by a Wilson plot. This may be attributed to the obliquely wound hollow fibers and complicated flow patterns on membrane surfaces in outside blood flow oxygenators. It is concluded that outside blood flow oxygenators are superior to the inside blood flow type because of significant differences in liquid-side boundary layer resistance.

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Thirty-nine patients were divided into the three groups; S group, Sarns membrane oxygenator (extracapillary); M group, MAXIMA (extracapillary); C group, Capiox (intracapillary). S group demonstrated significantly higher platelet counts compared with M and C group (p<0.01) and lower level of plasma free hemoglobin. M group also demonstrated higher platelet counts and lower level of plasma free hemoglobin. Leukocytosis and lactate levels were almost same among the three groups. In this study extracapillary type membrane oxygenators have lower priming volume, good gas transfer and better biocompatibility.

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