下腔静脉内氧合器的实验研究

检测静脉内氧合器（ＩＶＯＸ）的气体交换能力,了解ＩＶＯＸ植入体内后血栓形成、气检发生的情况。方法杂种大１２条,采用扩大死腔、气道给Ｎ２的方法造成低氧血症后,经髂总静脉向下腔静脉内植入ＩＶＯＸ,ＩＶＯＸ通Ｏ２。结果使用ＩＶＯＸ后ＰａＣＯ２明显降低（１９％,Ｐ＜０．０５）,但ＰａＯ２无明显升高（Ｐ＞０．０５）。８例ＩＶＯＸ有少许纤维蛋白形成,４例右房内有少许气栓形成。结论ＩＶＯＸ能较为有效地清除体内ＣＯ２,其加氧能力尚需进一步证实。     

不同氧合器对体外循环心脏手术患儿炎性反应的影响

体外循环（CPB）是由氧合器、血泵和其它装置组成的回路，在替代心肺功能、维持全身各脏器及组织代谢需要的同时，也诱发了机体全身炎性反应综合征（SIRS）。氧合器的应用是其诱发因素之一。氧合器的改进有助于降低CPB引起的SIRS。鼓泡式氧合器的工作原理是气血直接接触，膜式氧合器气血不直接接触，而是通过微孔型中空纤维膜将气体弥散入血进行氧合，中空纤维平行排列，内走气外走血。本研究拟比较鼓泡式氧合器和膜式氧合器对CPB下室间隔缺损修补术患儿炎性反应的影响，为合理选择氧合器提供参考。     

两种氧合器对心肺转流炎症反应的影响

目的动态监测室间隔缺损修补术患者在心肺转流(CPB)各时段血清可溶性细胞间粘附分子(sICAM-1)、可溶性E-选择素(sE-selection)及肿瘤坏死因子α(TNF-α)的变化规律,并比较西京-90鼓泡式氧合器和希健-Ⅱ膜式氧合器对其的影响。方法选择择期行室间隔缺损修补术的患者30例,随机均分为鼓泡式氧合器组(B组)和膜式氧合器组(M组)。所有患者分别在麻醉后CPB开始前(T1)、主动脉阻断开放前(T2)、CPB结束时(T3)、术后2h(T4)、6h(T5)、24h(T6)及48h(T7)取静脉血5ml用ELISA法测定sICAM-1、sE-selection及TNF-α的浓度。结果两组患者血清中的TNF-α于T2时开始显著升高,T4时达到峰值(P<0·01)。sICAM-1于T5时开始升高,T6时达峰值。sE-selection于T4时开始升高,T5时达峰值(P<0·01)。M组大部分时点TNF-α、sICAM-1、sE-selection的浓度均低于B组。结论希健-Ⅱ膜式氧合器引起的炎症反应较轻。     

不同氧合器对体外循环心脏手术患儿中性粒细胞凋亡的影响

目的 研究小儿体外循环(cardiopulmonary bypass,CPB)中不同氧合器对中性粒细胞(PMN)凋亡的影响,为减轻体外循环伞身炎症反应提供新的思路.方法 将60例室间隔缺损患儿随机分为两组(n=30):西京-90鼓泡式氧合器组(B组)和希健-Ⅱ膜式氧合器组(M组).分别于CPB前、CPB结束时、CPB结束后4、8、24 h 5个时点采取静脉血,以伞血细胞计数仪测定PMN数量,流式细胞仪测定PMN凋亡率和PMN表面黏附分子CD11b表达变化,ELISA法测定血浆弹性蛋白酶浓度.结果 两组患者CPB结束后PMN凋亡率明显降低(P<0.05),PMN数量、CD11b表达、血浆弹性蛋白酶浓度明显升高(P<0.05),在CPB结束时及CPB结束后4、8 h PMN凋亡率M组均高于B组(P<0.05);而PMN数量、CD11b表达、血浆弹性蛋白酶水平B组均高于M组(P<0.05).CPB结束后24 h PMN数量B组高于M组(P<0.05).结论 与西京-90鼓泡氧合器相比,应用希健-Ⅱ膜式氧合器可以减轻CPB对PMN凋亡的抑制,进而减轻全身炎症反应.     

不同氧合器对体外循环心脏手术患儿中性粒细胞凋亡的影响

Objective To evaluate the effect of two kind oxygenators on polymorphonuclear neutrophil (PMN) apoptosis, and to give a method of inhibting the systemic inflammatory response syndrome(SIRS) to cardiopulmonary bypass(CPB). Methods Sixty VSD patients undergoing open heart surgery with CPB were randomly divided into two groups(n = 30): group B(bubble oxygenator), group M(membrane oxygenator). Blood samples were drawn from the central venous line before starting CPB, at the end of CPB, 4, 8 and 24 h after CPB. The PMN counts were performed by blood cell counter. PMN apoptosis and the expression of CD11b were evaluated by flow eytometry. The plasma concentration of elastase was determined by enzyme linked immunosorbent assays. Results The rates of PMN apoptosis were significantly reduced (P<0.05) and the PMN counts, the expression of CD11b and the plasma con-centration of elastase were remarkably increased after CPB(P<0.05), but at the end of CPB, 4 h and 8 h after CPB the rate of PMN apoptosis was higher in group M than that in group B. PMN counts, the expression of CDI lb and the plasma concentration of elastase were higher in group B than in group M (P<0.05). The PMN counts were higher in group B than in group M 24 h after CPB (P< 0.05). Conclusion XiJian-Ⅱ membrane oxygenator can increase PMN apoptosis and depress systemic inflammatory response better than XIJing-90 bubble oxygenator.     

不同氧合器对体外循环心脏手术患儿中性粒细胞凋亡的影响

Objective To evaluate the effect of two kind oxygenators on polymorphonuclear neutrophil (PMN) apoptosis, and to give a method of inhibting the systemic inflammatory response syndrome(SIRS) to cardiopulmonary bypass(CPB). Methods Sixty VSD patients undergoing open heart surgery with CPB were randomly divided into two groups(n = 30): group B(bubble oxygenator), group M(membrane oxygenator). Blood samples were drawn from the central venous line before starting CPB, at the end of CPB, 4, 8 and 24 h after CPB. The PMN counts were performed by blood cell counter. PMN apoptosis and the expression of CD11b were evaluated by flow eytometry. The plasma concentration of elastase was determined by enzyme linked immunosorbent assays. Results The rates of PMN apoptosis were significantly reduced (P<0.05) and the PMN counts, the expression of CD11b and the plasma con-centration of elastase were remarkably increased after CPB(P<0.05), but at the end of CPB, 4 h and 8 h after CPB the rate of PMN apoptosis was higher in group M than that in group B. PMN counts, the expression of CDI lb and the plasma concentration of elastase were higher in group B than in group M (P<0.05). The PMN counts were higher in group B than in group M 24 h after CPB (P< 0.05). Conclusion XiJian-Ⅱ membrane oxygenator can increase PMN apoptosis and depress systemic inflammatory response better than XIJing-90 bubble oxygenator.     

840例复旦膜式氧合器的临床应用

复旦膜式氧合器是最早的国产膜式氧合器之一 ,上海市胸科医院自 1994年 9月至 2 0 0 0年 8月共应用 840例 ,现将临床应用经验总结如下。1　临床资料与方法本组共 840例 ,男 5 11例 ,女 32 9例。年龄 1.5～ 44岁 ,体表面积 0 .5～ 1.6 m2 。手术方式 :房间隔缺损修补术 34 5例 ,室间隔缺损修补术 32 8例 ,左心房粘液瘤摘除术 46例 ,肺动脉狭窄 39例 ,主动脉狭窄 31例 ,三房心纠治术 2 5例 ,其他复杂畸形纠治术 2 6例。全组病例采用常规体外循环方法 ,无血预充 ,中深度血液稀释 ,中度低温。2　结　　果全组病例体外循环时间 2 0～ 15 6分钟 ,…     

Development of a New Hollow Fiber Silicone Membrane Oxygenator: In Vitro Study

An experimental silicone hollow fiber membrane oxygenator for long-term extracorporeal membrane oxygenation (ECMO) was developed in our laboratory using an ultrathin silicone hollow fiber. However, the marginal gas transfer performances and a high-pressure drop in some cases were demonstrated in the initial models. In order to improve performance the following features were incorporated in the most recent oxygenator model: increasing the fiber length and total surface area, decreasing the packing density, and modifying the flow distributor. The aim of this study was to evaluate the gas transfer performances and biocompatibility of this newly improved model with in vitro experiments. According to the established method in our laboratory, in vitro studies were performed using fresh bovine blood. Gas transfer performance tests were performed at a blood flow rate of 0.5 to 6 L/min and a V/Q ratio (V = gas flow rate, Q = blood flow rate) of 2 and 3. Hemolysis tests were performed at a blood flow rate of 1 and 5 L/min. Blood pressure drop was also measured. At a blood flow rate of 1 L/min and V/Q = 3, the O2 and CO2 gas transfer rates were 72.45 +/- 1.24 and 39.87 +/- 2.92 ml/min, respectively. At a blood flow rate of 2 L/min and V/Q = 3, the O2 and CO2 gas transfer rates were 128.83 +/- 1.09 and 47.49 +/- 5.11 ml/min. Clearly, these data were superior to those obtained with previous models. As for the pressure drop and hemolytic performance, remarkable improvements were also demonstrated. These data indicate that this newly improved oxygenator is superior to the previous model and may be clinically acceptable for long-term ECMO application.     

Simple Evaluation Method of Biocompatibility of Artificial Oxygenator Hollow Fiber

Abstract: We made miniature modules filled with artificial oxygenator hollow fibers and conducted a simple experiment to study the effect of different membrane structures on the blood. Three types of modules were made: one filled with polyolefin, one filled with polypropylene, and a blank module. The 3 modules were connected through 3 fine tubings to one needle so that the same blood that passed through the 3 modules could be analyzed simultaneously. Nonheparinized blood was continuously withdrawn from 6 healthy volunteers using a small pump and passed through the circuit by a single pass (10 ml/min, for 10 min). Platelet count, thrombin-anti-thrombin complex, and complement-3 were measured in the blood collected at 10 min from the outlet of each module. The results showed significantly better biocompatibility of polyolefin than polypropylene, which is attributable to the dense layer of the blood contact surface of polyolefin fibers. This method is useful in assessing biocompatibility of various hollow fibers in a simple and safe manner.     

Gas Transfer Performance of a Hollow Fiber Silicone Membrane Oxygenator: Ex Vivo Study

Based on the results of in vitro studies of many experimental models, a silicone hollow fiber membrane oxygenator for pediatric cardiopulmonary bypass (CPB) and extracorporeal membrane oxygenation (ECMO) was developed using an ultrathin silicone hollow fiber with a 300 microm outer diameter and a wall thickness of 50 microm. In this study, we evaluated the gas transfer performance of this oxygenator simulating pediatric CPB and ECMO conditions. Two ex vivo studies in a pediatric CPB condition for 6 h and 5 ex vivo studies in an ECMO condition for 1 week were performed with venoarterial bypass using healthy calves. At a blood flow rate of 2 L/min and V/Q = 4 (V = gas flow rate, Q = blood flow rate) (pediatric CPB condition), the O2 and CO2 gas transfer rates were maintained at 97.44 +/- 8.88 (mean +/- SD) and 43.59 +/- 15.75 ml/min/m2, respectively. At a blood flow rate of 1 L/min and V/Q = 4 (ECMO condition), the O2 and CO2 gas transfer rates were maintained at 56.15 +/- 8.49 and 42.47 +/- 9.22 ml/min/m2, respectively. These data suggest that this preclinical silicone membrane hollow fiber oxygenator may be acceptable for both pediatric CPB and long-term ECMO use.     

Semipermeable Hollow Fiber Membranes in Hepatocyte Bioreactors: A Prerequisite for a Successful Bioartificial Liver?

Abstract: Recent studies have shown that liver support systems based on viable hepatocytes can prolong life in animal models of acute liver failure. Now the time has come to elucidate the design characteristics that are essential to construct an efficient bioreactor. The gold standard remains the intact liver. Despite the very high cell density in this organ, individual cell perfusion is guaranteed resulting in low diffusional gradients which are essential for optimal mass transfer. These conditions are not met in bioreactors based on hollow fiber membranes. Moreover, the semipermeable membranes can foul and act as a diffusional barrier between the hepatocytes and the blood or plasma of the recipient. We devised a novel bioreactor for use as a bioartificial liver that does not include hollow fiber membranes for blood or plasma perfusion. The device is based on an integral oxygenator and a nonwoven polyester matrix material for hepatocyte culture as small aggregates. The efficacy of this original design was tested in rats with liver ischemia. Preliminary results show statistically significantly improved survival; life was prolonged 100% compared to the control experiments.     

A New Hollow-Fiber Oxygenator for Clinical Cardiopulmonary Bypass

Abstract: A new hollow-fiber oxygenator has become available for clinical cardiopulmonary bypass. It is available in three sizes for adult use, ranging from 3.3 to 5.4 m². The surface area is dependent on the number of fibers, with blood and oxygen effecting very efficient gas transfer throughout the length of each of the fibers. The clinical experience now covers 100 patients, using the 3.3-m² device in 16 patients, the 4.3-m² device in 12 patients, and the 5.4-m² device in 72 patients. In all cases, the oxygenator has proven highly efficient in gas transfer. The addition of an oxygen-blending unit was found to be necessary to prevent overoxygenation. It is a safe and effective device to use in routine clinical practice.     

A Novel Blood Viscosity Estimation Method Based on Pressure‐Flow Characteristics of an Oxygenator During Cardiopulmonary Bypass

During cardiopulmonary bypass (CPB), blood viscosity conspicuously increases and decreases due to changes in hematocrit and blood temperature. Nevertheless, blood viscosity is typically not evaluated, because there is no technology that can provide simple, continuous, noncontact monitoring. We modeled the pressure‐flow characteristics of an oxygenator in a previous study, and in that study we quantified the influence of viscosity on oxygenator function. The pressure‐flow monitoring information in the oxygenator is derived from our model and enables the estimation of viscosity. The viscosity estimation method was proposed and investigated in an in vitro experiment. Three samples of whole bovine blood with different hematocrit levels (21.8, 31.0, and 39.8%) were prepared and perfused into the oxygenator. As the temperature changed from 37°C to 27°C, the mean inlet pressure (P_in) and outlet pressure (P_out) of the oxygenator and the flow (Q) and viscosity of the blood were measured. The estimated viscosity was calculated from the pressure gradient (ΔP = P_in ? P_out) and Q and was compared to the measured blood viscosity. A strong correlation was found between the two methods for all samples. Bland‐Altman analysis revealed a mean bias of ?0.0263 mPa.s, a standard deviation of 0.071 mPa.s, limits of agreement of ?0.114–0.166 mPa.s, and a percent error of 5%. Therefore, this method is considered compatible with the torsional oscillation viscometer that has plus or minus 5% measurement accuracy. Our study offers the possibility of continuously estimating blood viscosity during CPB.     

The Superiority of Hollow Fiber Membrane over Bubble Oxygenator in a Perfusion Circuit for the Evaluation of Small Caliber Endothelialized Arterial Prostheses

Abstract: A perfusion circuit was constructed from a pneumatic ventricular assist device, 2 compliance chambers, 4 small-diameter silicone tubes (ID 4 mm) simulating shear inducing vascular prostheses, and an oxygenator with a heat exchanger. A bubble oxygenator (in a BO circuit) and a hollow fiber membrane oxygenator (in an MO circuit) were studied. The circuits were perfused with 30% human serum containing culture medium for 7 days at 37^oC. The pH, Po₂, Pco₂, Na⁺, K ⁺, Ca^{2 +}, CI^-, glucose, and total protein concentrations remained the same in BO and MO circuits during the 7 days of perfusion. The differences between the values measured in the perfusion medium and in the medium maintained in the static conditions of cell culture were not significant. In the BO circuit, the amount of cholesterol and triglyceride concentrations decreased whereas the relative amounts of albumin, α1, α2, p, and γ globulins remained stable in the perfusion medium. The medium from the BO circuit did not promote the proliferation of cultured human saphenous vein endothelial cells. In the medium from the MO circuit, the cholesterol and triglyceride concentrations did not change with perfusion time; the proliferation rate and anticoagulant function of endothelial cells were maintained. The hollow fiber membrane oxygenator preserves the biological characteristics of the cell culture medium in a perfusion circuit. The MO circuit permits the performance of relevant studies on shear stress resistance and functional activity of human endothelial cells seeded onto vascular prostheses.     

Major Findings from the Clinical Trials of the Intravascular Oxygenator

Abstract: Major clinically relevant findings have been extracted and summarized from the database developed from the international multicenter clinical trials of the intravascular oxygenator (IVOX) as a means for augmenting the deficient blood gas transfer of patients in advanced acute respiratory failure (ARF). Between February 1990 and May 1993, a total of 164 IVOX devices were utilized in 160 clinical trial patients who were hypoxemic and/or hypercarbic while receiving closed system positive pressure mechanical ventilator support at or exceeding generally accepted minimum safe levels of intensity. The average rates of oxygen and carbon dioxide transfer into and out of circulating venous blood by means of the IVOX device varied from 40–70 ml/min. Evidence of patient benefit during IVOX utilization includes improvement in blood gas partial pressures associated with decreased intensity of mechanical ventilation, improved hemodynamics in patients with mechanical ventilator depressed cardiovascular function, and decreased indices of lung dysfunction. Clinically recognized IVOX–related complications or adverse events were reported in 24. 5% of the clinical trials patients. At necropsy examination of 68 clinical trials patients who died during or after I VOX utilization, forensic pathologists reported 4 cases in which IVOX utilization could have been a primary or contributing cause of death. Significant IVOX device mechanical and/or performance malfunction problems were recognized in 29 (17. 7%) of the IVOX devices utilized in clinical trials. IVOX clinical trials data collected and analyzed to date indicate IVOX utilization has a favorable risk/benefit ratio in patients in severe, acute, potentially reversible ARF.     

Development of an Intravascular Pumping Oxygenator Using a New Silicone Membrane

Abstract: A new intravascular pumping oxygenator (IVPO) was developed for intravascular gas exchange and circulatory assistance in critically ill patients with respiratory and circulatory failure. The IVPO utilizes new silicone hollow fibers (diameter. 1 mm: membrane width, 50 μm) and consists of two driving tubes for the oxygenation and pumping of circulating blood. The performance characteristics of the IVPO were studied using an experimental ex vivo model. With a mean hemoglobin concentration of 10.5 ± 2.3 g/dl, total oxygen transfer was 5.6 ± 1.5 ml/min at a blood flow of 200 ml/min and 6.3 ± 2.2 ml/min at a blood flow of 250 ml/min. Total CO₂ transfer was 3.8 ± 1.4 ml/min at a blood flow of 200 ml/min and 4.2 ± 1.6 ml/min at a blood flow of 250 ml/min during IVPO pumping. This preliminary experiment demonstrated that the IVPO has the capacity to function both as a circulatory assist pump and as an intravascular hollow fiber oxygenator.     

Long-Term Circulatory and Respiratory Support Using Two Artificial Ventricles and a Fluorocarbon Oxygenator

Using a new heart-lung machine developed at our Institute, experiments were conducted on dogs, donkeys, and monkeys, providing complete and assisted artificial circulation, assisted oxygenation, and perfusion preservation of the heart. The new apparatus consists of two sequentially mounted artificial ventricles working in an antiphase mode; blood oxygenation is accomplished by a reusable oxygenator with a fluorocarbon preoxygenator. Experimental results indicate that clinical use of the apparatus is promising and deserves consideration. The conditions of perfusion were close to physiological conditions and provided long-term survival of the animals. Performance in left ventricular bypass was optimized by monitoring myocardial PO2 and the state of the quick-connect/cut-off assemblies.