The effects of pulsatile flow on the leukocyte depleting qualities of the Pall LG6 leukocyte depleting arterial line filter: a laboratory investigation

The Pall LG6 arterial line filter has, in a previous publication, demonstrated its inherent leukocyte depleting qualities. This initial study was however carried out under continuous flow conditions. The present study was designed to assess the effectiveness of the LG6 filter in performing this leukocyte removal function under the more dynamic conditions of pulsatile flow. In addition to leukocyte depletion, the general blood handling and degree of energy absorption associated with the LG6 and Stat-Prime filters was also assessed. The results demonstrated that the LG6 filter was unaffected by the flow regime employed in terms of leukocyte removal and platelet depletion. There was a higher level of measured haemolysis associated with the use of pulsatile rather than nonpulsatile flow, however, this was the case with both filter types and was not found to be the case when generated values were computed. The LG6 filter absorbed more energy than the Stat-Prime filter as reflected by energy equivalent pressure (EEP) measurement, but this difference did not reach a level which was considered to be clinically significant.     

Ex vivo testing of the Quart arterial line filter

Arterial line filters are now routinely used in cardiac surgery in order to decrease the microemboli load to the patient. The Quart filter (Jostra, Hirrlingen, Germany) with a new planar construction design, an easy de-airing system and an integrated bypass, was tested for air filtration capacity and resistance to blood path in a standardized setting with surviving animals. Three calves (mean body weight: 71+/-3.4 kg) were connected to a standard cardiopulmonary bypass (CPB) circuit by jugular venous and carotid arterial cannulation with a mean flow rate of 3.5 l/min. The arterial line filter was challenged with upstream injections of boluses of air of 5, 10 and 15 ml, respectively. A Doppler ultrasound was positioned downstream on the arterial line to measure bubble count and size. The pressure drop through the filter was monitored at flow rates of between 1 and 6 l/min. At the end of the procedure the animals were weaned from the CPB and, thereafter, from the ventilator. After 7 days, the animals were sacrificed electively. This study shows that important quantities of air can be injected into the arterial line upstream of the filter with small volumes of small sized bubbles recorded downstream. With the 5 ml air bolus injection, mean values of 0.3+/-0.6 bubbles of 30 and 40 microm were detected, whereas with the 20 ml bolus, 32.6+/-8.7 bubbles of 10 microm, 3.7+/-1.1 bubbles of 30 microm, 3.3+/-0.6 bubbles of 40 microm and 0.7+/-1.1 bubbles of 50 microm were recorded. The blood path resistance at different blood flow rates was well within the acceptable range with a pressure drop of 20+/-0 and 26.6+/-5.7 mmHg at flow rates of 4 and 5 l/min, respectively. With its planar concept, the Quart filter offers good air filtering capacity both in terms of bubble count and size after injection of large boluses of air, without any increase of resistance to the blood path. Moreover, it offers a venting function and an integrated bypass system.     

白细胞髓过氧化物酶缺陷症的实验诊断

目的探讨白细胞髓过氧化物酶(MPO)缺陷症的病变特点及临床实验诊断策略。方法ADVIA 120血细胞分析仪分类计数白细胞和测定MPO指数(MPXI)，血涂片瑞氏染色观察白细胞形态和分类计数白细胞，血涂片过氧化物酶(POX)染色检测POX阳性细胞百分率和积分，流式细胞术单克隆抗体法分析白细胞MPO抗原表达水平。结果在5761例住院患者中，中性粒细胞MPO轻度缺陷病例占2．61％，部分缺陷占0．39％。3例典型MPO缺陷病例的ADVIA 120白细胞分析散点图出现特异性变化，MPXI减低，中性粒细胞和单核细胞的MPO活性和抗原表达呈不同水平减低，嗜酸性粒细胞正常。结论MPO活性减低是诊断白细胞MPO缺陷症的重要依据。Bayer ADVIA血细胞分析仪检查和血涂片白细胞过氧化物酶染色是其确诊的重要方法。     

去白细胞滤器滤除白细胞失败原因分析

目的研究去白细胞滤器滤除白细胞时导致滤盘不通的血液因素。方法选择40份去白细胞滤器滤白失败的血液标本和50份正常的血液标本,分别检验其血液流变学指标(全血黏度,红细胞刚性指数,红细胞聚集指数),血细胞比容,纤维蛋白原浓度,三酰甘油浓度。若疑有冷凝集素的血样做血清冷凝集素效价试验。结果全血黏度(低切、高切)和红细胞刚性指数增高(P<0.05),以及冷凝集素水平增高对白细胞滤器滤除白细胞有影响。血细胞比容、纤维蛋白浓度、三酰甘油浓度的高低不会影响白细胞滤除(P>0.05)。结论全血黏度、红细胞刚性指数、冷凝集素是导致去白细胞滤器滤除白细胞失败的主要血液因素。     

Strategy of leukocyte filtration for immunomodulation: development of stainless steel leukocyte filter.

Commercially available leukocyte filters are frequently used to prepare leukocyte depleted blood products for prevention of transfusion reactions. Recently, immunomodulation by using leukocyte filtration was evaluated. At this time, a new leukocyte filter was fabricated with a 4 microm diameter stainless steel fiber. The goal of this study was to assess the efficiency of the stainless steel filter for leukocyte and platelet removal by comparison with the polyester filter that is commercially available. The production of humoral factors, including interleukin-1 beta, tumor necrosis factor-alpha, and interleukin-1 receptor antagonist (IL-1 Ra), was also evaluated. The results show that the stainless steel filter has more than 2 times greater efficiency in leukocyte removal than the polyester filter. Furthermore, the cytokine studies indicate good biocompatibility of the filter, and the stainless steel filter has a possibility of inhibiting inflammatory cytokines by inducing interleukin-1 receptor.     

Laboratory evaluation of the bleeding patient

The laboratory evaluation of bleeding patients is often inaccurate and incomplete when the history and physical examination are not adequately evaluated. Using such information the next step is to use screening tests to evaluate platelet numbers and function, clot formation and clot stability and then to proceed to appropriate follow-up testing when indicated. In this way the number of tests can be significantly reduced and an accurate diagnosis becomes more likely.     

Thrombolyzer Compact-X全自动血凝仪的性能评价

目的 评价Thrombolyzelyzer Compact—X全自动血凝仪的技术性能。方法 参照ICSH和NCCLS有关文献对该仪器所检测的凝血酶原时间、活化部分凝血酶原时间、凝血酶时间及纤维蛋白原等项目作了精密度、准确性、交叉污染率和抗干扰能力测试。结果 该仪器的检测精密度达到NCCLSC24-A的要求，纤维蛋白原的平均回收率达105．7％，并显示出较强的抗干扰能力和极微的交叉污染率。结论 该仪器完全能满足临床实验室的要求。     

去白细胞输血器对新鲜冰冻血浆中凝血因子的影响

目的　探讨经白细胞过滤器过滤后的新鲜冰冻血浆 ( fresh frozen plasma,FFP)中凝血因子的生物活性变化。方法　随机抽取 A型、B型、O型、AB型新鲜冰冻血浆各 1 0 0 ml× 5袋 ,3 7℃水浴融化 ,在净化台内留取滤过前后血浆样本各 1 ml,使用德国 BE全自动血凝仪测定活化部分凝血酶时间 ( APTT)、凝血酶原时间 ( PT)、凝血酶时间 ( TT)、纤维蛋白原( Fbg)、凝血因子 ( F ∶C)、凝血因子 ( F ∶C)、凝血因子 ( F C)∶水平。结果　过滤前后的新鲜冰冻血浆 APTT、PT、TT、F ∶ C、F ∶ C、Fbg水平的差异均无显著性 ( P>0 .0 5 )。 F ∶ C过滤前后的差异有显著性 ( P<0 .0 5 ) ,但仍在参考值范围内。结论　过滤前后新鲜冰冻血浆中凝血因子的活性差异变化在参考值范围内 ,适用于临床治疗     

Laboratory evaluation of anatomic disorders of the thyroid

Thyroid function tests, radioiodine uptake and scintiscanning, and antithyroid antibody titers are the main laboratory tests useful in the management of goiter. Scintiscanning and ultrasonography aid in differentiating a functioning adenoma from a "cold" solid nodule--a crucial distinction since the incidence of cancer in a cold nodule is 20 percent. Radioiodine scanning and serum thyroglobulin help in the diagnosis of a well-differentiated thyroid cancer. Serum calcitonin serves as a reliable tumor marker for medullary carcinoma.     

Laboratory and clinical evaluation of the MAX transport ventilator

Transport of critically ill, mechanically ventilated patients from intensive care units for diagnostic and therapeutic procedures has become common in the last decade. Maintenance of adequate oxygenation and ventilation during transport is mandatory. We evaluated the Hamilton MAX transport ventilator in the laboratory and in the clinical arena to determine its usefulness during in-hospital transport. METHODS: In the laboratory, we determined the MAX's ability to assure tidal volume (VT) delivery in the face of decreasing compliance of a test lung, and we tested the alarm system. Using a two-compartment lung model modified to simulate spontaneous breathing, we also evaluated the responsiveness of the demand valve. The clinical evaluation was accomplished by comparing arterial blood gases and ventilator settings in the intensive care unit to those during transport. RESULTS: As lung compliance was reduced from 0.1 to 0.02 L/cm H2O [1.0 to 0.20 L/kPa], delivered VT fell significantly at each set VT. The alarm systems performed according to manufacturer's specifications. The demand valve triggered appropriately without positive end-expiratory pressure (PEEP), but as PEEP was increased, triggering became more difficult. The demand valve is referenced to ambient pressure and cannot compensate for elevated end-expiratory pressures. During patient transport, arterial blood gases were comparable to those achieved in the ICU. Because an inspired oxygen concentration of 1.0 was used during transport, arterial oxygenation (PaO2) was significantly greater (123 +/- 75 vs 402 +/- 85 torr [16.4 +/- 10 vs 53.6 +/- 11 kPa]). A higher ventilator rate was required during transport to prevent tachypnea (7 +/- 3 vs 12 +/- 6 breaths/min), and peak inspiratory pressure (PIP) was higher during transport (40 +/- 8 vs 52 +/- 11 cm H2O [3.9 +/- 0.8 vs 5.1 +/- 1.1 kPa]). CONCLUSIONS: The MAX is a reliable transport ventilator, capable of maintaining adequate ventilation and oxygenation in a majority of mechanically ventilated patients. Care should be taken to assure adequate VT delivery at high PIP, and ventilator rate may require adjustment to prevent tachypnea associated with triggering the non-PEEP-compensated demand valve when PEEP greater than 8 cm H2O [0.8 kPa] is used.     

Investigation of a new in-line leukocyte reduction filter for packed red blood cells

Background and objectivesOccasionally there are adverse transfusion reactions in the therapeutic use of packed red blood cells. Some of those reactions are caused by the presence of white blood cells (WBCs). Both immunogenic and infectious transfusion reactions are significantly influenced by the level of white blood cell contamination.Materials and methodsThe flexible in-line red cell filtration system Leucoflex LCR Diamond (Macopharma) was investigated. According to manufacturer information the system has a smaller filter surface (46 cm²) than the previous filter LCR-5 (53 cm²). Main difference with the previous model is the rhomboid design. The filter tube connections are not at the level of the centre edge, but at two opposite corners. Eighteen red cell concentrates were produced under Good Manufacturing Practice conditions in routine operation. To ensure the quality of the filter system every 7 days metabolic parametres such as WBC count, haemoglobin content, haemolysis rate, potassium load, pH and ATP content were analysed over a storage period of 49 days.ResultsThe mean product volume was 260.7 mL after filtration. Average haemoglobin content was 51.8 g per unit and WBC contamination was 0.02 × 10⁶ per unit. Haemolysis rate was 0.05% directly after filtration and 0.20% at the end of storage. Immediately after filtration the potassium concentration was 1.3 mmol/L and the pH was 7.37. During whole storage time the ATP level was maintained above 2.0 μmol per g haemoglobin.ConclusionThe tested filtration system is suitable for quality-assured production of red blood cell concentrates meeting national and international guidelines.     

On the dynamic performance of the Abbott Safeset blood-conserving arterial line system

Objective. Critically ill patients frequently have indwelling arterial lines placed during their Intensive Care Unit stay. The lines are used to monitor blood pressure continuously, administer drugs and to draw blood for a variety of physiologic tests. Several blood-conserving arterial line systems have been developed to eliminate the need to discard blood in the process of obtaining undiluted and uncontaminated blood samples. The purpose of this study was to evaluate the dynamic performance of one such system – the Abbott Clinical Care System Safeset blood conserving arterial line system – in comparison to a conventional arterial line system. Methods. We studied ninety-nine patients who had indwelling arterial lines placed during surgery and who were admitted to our Surgical Intensive Care Unit (SICU). The patients were randomly placed into one of two groups. The control group received a conventional indwelling arterial line system; the experimental group received the Abbott Safeset system. We measured the damping coefficient and resonant frequency daily in order to evaluate and compare the dynamic performance of the two systems. We also measured discard volumes (in the control group) and blood sample sizes during the patients stays in the SICU. Results. The two patient groups were similar in regards to demographics and baseline clinical characteristics. A median 3 ml of blood per draw and 17.5 ml of blood per patient was discarded in purging the conventional arterial line system while, by design, no blood was discarded with the experimental system. There was no difference between the two groups with regard to damping coefficient. Both systems were underdamped. However, the conventional arterial line system had a significantly higher resonant frequency (16.7 Hz) compared to the Safeset system (12.5 Hz). Conclusions. Because the Abbott Safeset blood-conserving arterial line system is underdamped and has a lower resonant frequency compared to the traditional arterial system, it may overestimate systolic blood pressure, particularly in patients with high heart rates.     

Laboratory evaluation of hyper- and hypoglycemic states

Appropriate use of test strategies requires not only an appreciation of analytic considerations and the ability of the tests to confirm or exclude the hypotheses, but also an understanding of the underlying pathophysiology and clinical features of the problems to be addressed. This discussion covers disease definition, pathophysiology, analytic considerations, and strategies for diagnosis and management.     

不同滤器制得的去白细胞悬浮红细胞在不同保存期的相关指标比较

目的探讨不同生产厂家滤器制得的去白细胞悬浮红细胞在不同保存时间时相关指标优劣。方法随机使用4个厂家带白细胞滤器的一次性采血袋采集200、300、400mL全血,然后分别制备为1U、1.5U及2U的去白细胞悬浮红细胞共240袋,分别按照不同规格保存于(4±2)℃储血专用冰箱。使用无菌接驳器分别取同一规格、不同厂家的保存期为0、7、14、21、28和35d的悬浮去白细胞悬浮红细胞标本共计240份,测定其血容量、血细胞比容、白细胞残留量、血浆游离血红蛋白(FHb)水平、血红蛋白水平、并计算其储存期末溶血率。结果同一厂家滤器制备不同规格悬浮去白细胞红细胞效果差异无统计学意义(P0.05);不同厂家滤器制备的同一规格悬浮去白细胞红细胞在血容量、血浆FHb水平方面比较,差异有统计学意义(P0.05);同一厂家滤器制备的悬浮去白细胞红细胞在不同储存期的FHb、保存期末溶血率差异有统计学意义(P0.05)。结论应从血细胞比容、FHb水平、溶血率等指标综合考虑,选择带白细胞滤器的一次性采血袋,以确保去白细胞效果及红细胞输注的安全性和有效性。