A new portable apparatus was developed for non-invasive monitoring of the oxygenation state in human brain. Oxy Hb, deoxy Hb and total Hb content in the brain was measured by near infrared spectrophotometry. Brain oxygenation and blood volume change were continuously monitored in cardiopulmonary bypass (CPB) patients in reflectance mode. During CPB, the brain oxygenation level was maintained roughly constant at mean perfusion pressure over 60mmHg, whereas below 50mmHg the apparent decrease in oxy Hb content was observed. In conclusion, non-invasive monitoring of cerebral oxygenation using NIR light can provide valuable data at bed side about tissue metabolism and allow for the proper management of critical surgical patients.

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Blood flow velocity of the middle cerebral artery (VMCA) was monitored during extracorporeal circulation (ECC) by means of transcranial Doppler ultrasonography (TCD). Mean VMCA measured before ECC was 14.0cm/sec. VMCA during ECC and after ECC increased significantly to 18.4cm/sec, 27.0cm/sec (p<0.01). Oxygen transport index calculated by oxygen content X VMCA, was 254.9 before ECC and changed to 197.1, 326.6 during ECC and after ECC.

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The computer monitors central venous pressure (CVP), aortic pressure (AoP), reservoir blood level and collapse status with a sampling period of 1 second, blood and patient's temperature with a sampling period of 30 seconds. The change of blood volume (blood transfusion, medicine, urine, etc.), are entered by keying operation. The computer checks that parameters are within limits and displays the change of parameters. The computer is able to control both infusion and withdrawal pumps to maintain CVP to the desired level. The system is operated as a recording system in five clinical cases, and can be operated easily and quickly.

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Between January 1986 and July 1989, cardiopulmonary bypass without blood priming was attempted in 55 patients, During the course of hospitalization no blood transfusion was used in five of seven patients with the body weight under 20kg, in nine of 11 patients weighing between 20 and 30kg, and in 30 out of 37 patients weighing more than 30kg. With proper case selection, open heart surgery without blood transfusion was possible even in patients weighing less than 20kg.

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In open heart surgery, cold blood cardioplegia and blood conservation seemed to be incompatible. To solve this problem, we made a new independent cold blood cardioplegia circuit with miniaturization of extracorpoleal circulation circuit. In addition, we used an autologous blood transfusion circuit (cell saver) intra- and postoperatively. In 94 patients treated after the adoption of this method, blood conservation and incidence of hepatitis were compaired with those in prior 82 patients. The avarage volume of blood transfusion was reduced to 1048.8ml from 3362.0ml. In 30 patients (31.9%) including 2 Bentall operations and 2 surgery for thoracic aneurysm, no blood transfusion was required. Incidence of hepatitis was reduced to 3.2% from 23.2%. Consequently, it was concluded that complete non-transfusion surgery is not always incompatible with cold blood cardioplegia by using this method.

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To determine whether the CELL SAVER (CS) could reduce blood transfusion volume in the open heart surgery, multiple regression analysis for the transfusion volume and discriminant analysis for non-blood transfusion surgery, were performed using perioperative 21 factors including a factor of CS use in 106 patients open heart surgery. Both analysis revealed that CS use remained significant factor for transfusion volume reduction or non-blood transfusion surgery even after reduction of 21 to 6 factors in multiple regression analysis and 21 to 4 factors in discriminant analysis, in addition to the fact that the transfusion volume reduced 3288 to 1473ml by the introduction of CS and that the incidence of resultant serum hepatitis reduced 25.9 to 12.5%. Thus these results suggest that CS might be of clinical use in terms of reduction of transfusion blood volume in open heart surgery and the incidence of resultant hepatitis.

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In randomized prospective study of patients having cardiac surgery, Autotransfuse utilizing was employed during the open-heart surgery and residual blood in the heart-lung circuit was collected and administered in 62 patient (group I), whereas 30 patients underwent operation without autotransfusion (group II). Comparison of the two groups showed no significant difference in regard to age, sex, operation performed or operative time. Although mean postoperative bleeding was similar in the two groups (postoperative blood loss; 149±93ml in group I versus 220±131ml in group II), homologous blood transfusion was reduced significantly in group I (672±623ml in group I compaired with 2593±1964ml in group II)(p<0.01). Although plasma free hemoglobin measured before and after reinfusion of residual blood increased from 30±18mg/dl to 55±27mg/dl, postoperative renal failure did not develop in any patients of group I and there was no significant difference of serum creatinine between the two groups. We conclude that usage of Cell Saver and reinfusion of residual blood can reduce the volume of transfused homologous blood and are useful aids to blood conservation.

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We examined the effect of intraoperative autotransfusion (Cell Saver-4 or Stat) on harologous blood usage with or without preoperative autologous blood preservation. The results demonstrated combined intraoperative autotransfusion and preoperative blood preservation method could significantly reduce blood usage, however, autotransfusion method alone could not reduce it enough. Our data suggest that we will be asked to preserve a little more autologous blood and to salvage platelet and plasma in order to complete cardiac operation without homologous blood transfusion.

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Intraoperative blood salvaging autotransfusion using a Haemonetics Cell Saver IV was performed in 14 adult patients undergoing open heart surgery, and the blood aspirated from the surgical field (the aspirated blood) and the residual blood in the cardiopulmonary bypass circuit (the residual circuit blood) were separated, washed, and retransfused with the Cell Saver. Hemolysis in the aspirated blood and the residual circuit blood was compared and discussed in relation to salvage rates, their Free-hemoglobin concentrations in the salvaged blood, and the free-hemoglobin volume in waste. In the aspirated blood the salvage rate was lower, the freehemoglobin concentration in the salvaged blood was higher, the free-hemoglobin volume in the waste was larger than in the residual circuit blood. Therefore, in the autotransfusion of the residual circuit blood, the direct retransfusion or the ultrafiltration method can be used, but in the autotransfusion of the aspirated blood, cell separation and washing of the blood appear necessary.

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We developed intraoperative multi-functioned blood saving system (Hemosaver) which incorporated ultrafiltration volume controlled hemoconcentrator, intraoperative autotransfusion unit and blood cardioplegia delivery unit in order to save blood during the operation. This system is consisted of two roller pumps, two infusion pumps, digital flow meters and a cold water supply unit. Autotransfusion unit is non-washing and regional heparinization in the circuit of the unit. Hemoconcentrator allowed easy estimation of hematocrit after ultrafiltration.

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A clinical study of the hollow fiber membrane type oxygenator with systemized defoamer was performed on 15 patients. This oxygenator contains approximately 71000 microporous, polypropylene hollow fibers, with a total membrane surface area of 5.8m². The pressure drop between inlet and outlet of the oxygenator was 80mmHg. Blood gas analysis during perfusion showed good oxygenation. In the hematological data, platelet index (platelet counts/hematocrit) did not significantly decrease during perfusion. The plasma free hemoglobin increasing rate was 0. 50±0. 19mg/dl/min. This oxygenator easily breaks up gaseous macro and microemboli at the time of priming and during perfusion. The present study indicates that this oxygenator would be suitable for clinical application.

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We used MERA hollow fiber membrane oxygenator Excelungα in 18 cases to study gas transfer, hemolysis, and pressure drop during extracorporeal circulation. The ratio of the effective blood flow of the oxygenator was 0, 79-0.91. The ratio of CO2 partial pressure during 30-150min.from start was 0, 09-0.12 and at 180min.was 0.14. Free hemoglobin in the control was 3.9±2.7mg/dl, decreasing to about 50% of the control. The platelets decreased from 56.3±1.4 (×10/%) to 2.85±0.9(×10/T). Pressure drop increased from 10mmHg at flow rate of 11/min. to 136mmHg at 61/min.

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The performance of gas transfer, heat exchange efficiency and pressure drop of a new oxygenator, HF-5000 was evaluated. This oxygenator is extracapillary blood flow type hollow fiber membrane oxygenator (sureface area: 3.7m², priming volume: 560ml) and has a heat exchanger made of polyurethane. HF-5000 has excellent O₂ transfer performance, good CO₂ transfer performance, good heat exchange efficiency and low pressure drop. This study indicates that this oxygenator would be adaptable for clinical application.

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Problems of long-term perfusion with membrane oxygenator are adsorption of plasma protein on the surface of the membrane and plasma leakage through micropore. A study of membrane lung oxygenated with high frequency positive pressure ventilation (HFPPV) is described. Membrane lung was vibrated by HFPPV and 6Hz was most effective in oxygenation in vitro. Extracorporeal circulation (ECC) of membrane lung for 8hr with HFPPV revealed efficiency of oxygenation maintained continuously in animal experiments, although oxygenation without HFPPV was also sufficient. SEM study after ECC showed that the membrane with HFPPV absorbed less protein layer involving fibrin than that without HFPPV. Protein layer on polypropylene melnbrane was suspected to consist of r-globulin and fibrinogen.

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The high peak flow velocity of the extremely effective pulsatile monoroller pump (MRP) recently described (Jpn J Artif Organs 17 (3): 1248-54, 1988) precludes its direct use in conjunction with commercially available membrane or hollow fiber type oxygenators. A new hybrid coaxial pump (DUAL PUMP) combining in-series a conventional biroller pump placed upstream the MRP has been developed to solve such shortcomings. The biroller pump propels the blood FROM or THROUGH ANY TYPE OF OXYGENATOR into a small bag type reservoir connected to the inlet side of the MRP. The diameter of both pump head raceways has been calculated so that the biroller pump flow is 10% to 20% higher (overflow) than the MRP flow. A simple mechanical flow mode selector externally placed around the tubings of the circuit between the pumps and the bag reservoir capable to convert the in-series arrangement of both pumps into two circuits in-parallel has been incorporated, thus allowing changing mode of perfusion (pulsatile to non-pulsatile or vice versa) instantaneously. The stroke volumes obtained in the mock circuitare dependent on the internal diameter (ID) of the tubing: a) 18mm ID=122-142ml, b) 15mm ID=80-90ml, c) 12mm ID=45-65ml, and d) 9mm ID=33-35ml. The lowest overflow is obtained with the best matching tube of 15mm ID for which the raceways were originally calculated, and considered to be the most adequate size for use in adults. The ideal pump head tube eleasticity to be used in the MRP is that offered by the MS-MERA PVC tubing.

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Camparative studies on SARNS-16310 and Masterflo 50 membrane oxygenator.New method of pumpless ECMO using two different membrane oxgenator was done in 13 dogs. During ltPA-LA bypass, blood pressure is stable, bypass flow was 20-60% of C. O., and gas transfer was efficient. There was no significant difference between two different oxygenator abut these parameters. This method maybe usefull for the implantable artificial lung.

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In order to examine the influence of cardiopulmonary bypass (CPB) on extravascular lung water volume (ELWV), the measurement of extravascular thermal volume (ETV) by a double indicator dilution was evaluated in patients who underwent mitral valve replacement and coronaryartery bypass operation. The results were as follows. 1) Post operative ELWV in patients was not increased. 2) The immediate postoperative ELWV in patients who underwent mitral valve replacement was significantly decreased. 2) It was difficult to assess the ELWV quantitatively with cardiopulmonary functional parameters.

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This study, included 20 patients undergoing cardiac surgery with extracorporeal circuration (ECC), was performed to investigate the effect of Aprotinin (AP) on hemostatic mechanisms during ECC. Eleven of these patients were control group. AP group included other 9 patients who had administrated AP (1500KIU/kg) at start of ECC. In both group, TAT and α₂ PI-PmC were increased immediateiy after the start of ECC. TAT was less in AP group than in control group, and the fibrinolytic parameters indicated the prevention of fibrinolytic activity by AP. Perioperative blood loss were significatnly less in AP group than in control group. But there was no significant differnce in platelet activity between both groups.

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The efficacy of three different membrane oxgenators (Capiox II, Capiox E, Sarns 16310) in decreasing the blood requirements in cardiacoperations was studied in 39 patients. There were no significant differences in preoperative body weight, preoperative and postoperative hematocrit value, platelet counts, duration of extracorporeal circulation and the amount of post operative drainage. The blood requirements during hospitalization were 13.9±1.7 units in Capiox II group, 11.4±1.6 units in Capiox E group, 5.5±1.3 units in Sarns 16310 group. The use of the membrane oxygenator with a small amount of priming volume is very usefull in reduction of blood utilization.

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Effect on two method which post bypass hemoconcentration, post bypass cell saver method on wllite blood cell function were studied in each 15 patients. Both methods concentrated white blood cell like as red blood cell. Lymphocyte was not inflenced in the hemoconcentration method. The number of neutrophil was decreaced and the production of super oxide was also decreased in the hemoconcentration method. Neutrophil was not inflenced in the Cell saver method. The stimulation index of lymphocyte transformation (PHA) was decreaced by the elvation of control value.

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In 62 cases of open heart surgery, autotransfusion of concentrated selected washed red cells from surgical field was carried out. The use of automated Cell Saver made it possible to save 621ml of homologous blood. In 54% of these cases, the open heart surgery was performed without any homologous blood transfusion.
There was no difference in intraoperative and post operative laboratory examinations between cases with no blood transfusion and with homologous blood transfusion.
Plasma free hemoglobin level was high in the Cell Saver processed blood. Bacterial culture was possitive in 51.7% of processed blood. It was concluded that these findings should be in mind when Cell Saver processed blood is used.

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Clinical application of centrifugal pump was reported in conparison with roller pump. We analyzed the Changes on red cell deformability and some other hematological parameters. Results were obtained as follows, in centrifugal pump group, red cell deformability was preserved better than in roller pump grroup. But there was no significant difference between two groups. Red cell resistance to osmolality was preserved during cardiopulmonary bypass in both groups. No significant difference was noticed in regard to the amunt of hemolysis and platelet Count.
In this cliniCal application, it is considered that centrifugal pump has no hematological advantage in comparison with roller pump during cardiopulmonary bypass.

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Arterial or left heart bypass using Bio-pump with Anthron shunt tube (Bio-pump bypass) was performed for the recent descending aorta operations (8 cases) as temporary bypass. Haemodynamical differences during aortic clamp between Bio-pump bypass and axillo-femoral temporary bypass without use of Bio-pump (simple bypass) which had carried out before (4 cases) were compaired. In the results, peripheral blood flow and urinary output during aortic clamp were signifficantly increased in the Bio-pump bypass group compaired with the simple bypass group. These results indicated that the Bio-pump bypass was usefull method as temporary bypass especially for high risk patients having lower renal functions or hypertentions. And, it seems that complications caused by thrombus formations would be reduced by use of Anthron shunt tube which has superior antlthrombogenecity.

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Left heart assist deviced. eveloped in our laboratory has been substituted for a roller pump in heart lung machine. This system has been tested in mock circulation and in 7 dogs in total extracorporeal circulation. Circulation was maintained automatically in the entire course of profund hypothermia and rewarming in all dogs. No manual adjustment of the pumping was necessary.

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We investigated safety and blood compartibility of a prolonged veno-venous extracorporeal lung assist (ECLA) with a heparin bonded artificial membrane lung and circuit (CARMEDA, SWEDEN) in 18 goats. ECLA was performed with a non-heparin bonded lung in group I, a heparin bonded lung re-sterilized by ethylene oxide gas in group II, a heparin bonded lung in group III. Activated coagulation time was maintained about 200 seconds in group I, 120-130 seconds in groupII, III by continuous infusion of a small amount of heparin solution. An average of bypass bl00d flow and bypass duration was 46.0ml/kg/min., 6.7 days in group I, 36.5ml/kg/min., 7.8 days in group II, 41.3ml/kg/min., 7.8 days in group III. A meandose of heparin administered was 26 units/kg/hr. in group I, 17 units/kg/hr. in group II, 14 units/kg/hr. in group III. The dose of heparinin group II, III were less significantly (p‹0.05) than in group I. Among three groups, there were no large difference in platelet-coagulation system except fibrinopeptide A which increased significantly (p‹0.05) in group II compared with group III. A reexporsure of a heparin bonded membrane lung to ethylene oxide gas may decrease antithrombogenecity, however, the heparin bonded surface provides excellent blood compartibility during a prolonged ECLA.

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Investigated was the effectiveness of ECUM during CPB to manage the kidney function of the cardiac surgical patients with renal failure. Mean removal of water and solute by ECUM was 67.3ml/kg and215.8mOsm and average ECUM-to-urine excretion ratio of water and solute was 9.7 and 10.7 respectively and reduction of plasma osmolarity (azotemia) was observed in these patients. Patients with chronicrenal failure tend to be olyguria in both hyper- and hypo-osmolar condition. So the reduction of exessive solute/water intake during CPB by ECUM is important in patients whose urine is watery and little.

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