Enhanced Fluid Removal Guided by Blood Volume Monitoring During Chronic Hemodialysis

Fluid overload predisposes chronic hemodialysis patients to cardiovascular disease, a significant cause of morbidity and mortality in these patients. We evaluated the efficacy of monitoring changes in blood volume during routine hemodialysis to detect fluid overload. Intradialytic changes in blood volume were monitored by continuously measuring hematocrit in all 56 patients in a single dialysis unit over 7 weeks. After Week 1, patients were categorized into 2 separate groups depending on their maximum intradialytic decreases in blood volume. In Group 1, 46 of 56 or 82% had greater than a 5% decrease in blood volume while in Group 2, 10 of 56 or 18% had less than a 5% decrease in blood volume. During Weeks 2–7, dialytic fluid removal was intentionally increased in Group 2 patients by 0.80 ± 0.62 L (mean ± SD) or 47 ± 43%. This intervention resulted in a larger (p < 0.02) intradialytic decrease in body weight (2.7 ± 0.9 kg versus 2.0 ± 0.8 kg) and a larger (p < 0.02) intradialytic decrease in blood volume (15 ± 5% versus 4 ± 1%) than experienced during Week 1 with a low incidence of symptoms. We conclude that there is a significant percentage of chronic hemodialysis patients who can tolerate additional fluid removal without hypovolemic symptoms even though they are considered to be at dry weight by routine physical examination and that the identification of these patients can be facilitated by intradialytic blood volume monitoring.     

中国健康人两项血液流变学参考值与海拔高度的关系

为制定中国健康成年男性血沉参考值(温氏法)和中老年女性红细胞压积参考值(温氏法)的统一标准提供科学依据,本文研究了中国226个单位测定的22707例健康成年男性的血沉参考值(温氏法)和312个单位测定的15608例健康中老年女性的红细胞压积参考值(温氏法),并对其与海拔高度的关系进行了研究,发现随着海拔高度的逐渐增大,健康成年男性血沉参考值(温氏法)在逐渐的减小,而健康中老年女性红细胞压积参考值(温氏法)在逐渐的增大,相关性都很显著。用回归分析的方法推导出了二个一元回归方程。如果知道了中国某地的海拔高度,就可以用这二个回归方程,估算这个地区的健康成年男性血沉参考值(温氏法)和健康中老年女性红细胞压积参考值(温氏法)。     

Determination of blood viscosity in vitro with a microglass fiber viscosimeter

Summary The micro-rheological property of blood was investigated with a new micro method. Principle: a glass fiber ( 10 , l=2.0 cm), driven by a constant force, traverses a blood sample. The speed of the glass fiber is directly proportional to the viscosity of the blood. Because of the small diameter of the fiber, the method is considered to be more sensitive to the intercellular friction of the erythrocytes. The methodical error was less than ±2%. The values obtained with the new method resembled those of coaxial viscosimeters.     

Hemoglobin levels in Tibet: different effect of age and gender for Tibetans vs Han

Tibetans form a population which has resided on the Qinghai–Tibetan plateau for thousands of years, and are reported to have less hemoglobin than Han Chinese lowlanders who have migrated to the plateau. However, for various altitudes, detailed comparisons of hemoglobin in the two ethnic groups has not been reported. We investigated the hypothesis that the effects of altitude, age, and gender on hemoglobin concentration would differ between Han and Tibetan residents of the plateau. Hematological parameters for both genders were determined in healthy Tibetan adults (n=3,000) and children (n=332), and healthy Han Chinese adults (n=2,612) and children (n=275), aged 5–60 years living at four different altitudes (mean altitude of 2,664, 3,813, 4,525, and 5,200 m). Hemoglobin values increased with altitude for all ages in both ethnic groups and in both genders. The gain in hemoglobin with altitude had the rank order: Han males > Han females > Tibetan males and females. Even before puberty, Han children had more hemoglobin than Tibetan children. An effect of age on hemoglobin was seen at the time of puberty in men, but not in women. A positive correlation was found between hemoglobin concentration and age in adult Han males and females, but not in Tibetan males, and only at the higher altitudes, in Tibetan females. In both Tibetans and Hans, males had higher hemoglobin values than females at each altitude, but the gender differences increased with altitude in Han, whereas it either decreased or did not change in Tibetans. Examination of hemoglobin levels by histogram showed non-Gaussian distributions: Tibetan men and women had skewing to higher values, whereas Han men and women had skewing in the opposite direction. We conclude that increasing age and the effect of gender in Tibetans are associated with different hemoglobin responses to altitude than in Han, and we speculate that genetic influences may be involved.     

Quantitative displacement of blood acid base equilibrium in acutely water depleted dogs

Summary Dogs were water depleted 2% of their body weight by the intraperitoneal injection of a hyperosmotic solution of saline and glucose (550 mOsm/l). During a 3-h experiment these water-depleted (WD) animals showed a significant decrease in blood pH, base excess (BE) and plasma bicarbonate (Bic_p) and an increase in both hematocrit (Ht) and blood buffer capacity (BBC). These changes were quantitatively time-dependent. The rate change of pH, BE, and Bic_p were –0.072 units h^–1, –4.7 mEq/l h^–1, and 2.9 mEq/l h^–1, respectively. As control dogs showed no significant time-dependent changes in their blood acid-base status, the observed modifications in the experimental dogs were ascribed to water depletion. Increased endogenous acid production related to tissue hypoxia is suggested to be the mechanism that could explain the increased fixed acid accumulation observed in the water-depleted animals.     

Quality validation of platelets obtained from the Haemonetics and Trima Accel automated blood-collection systems

BackgroundPlatelet transfusion is required to treat haemo-oncology or trauma patients. Platelet apheresis (PA) performed with apheresis equipment has increased rapidly in recent years. Leucocyte-reduced platelet apheresis (LRPA) can reduce the risk of platelet refractoriness and febrile nonhemolytic transfusion reactions (FNHTRs) for transfusion. Accordingly, this study aimed to investigate and compare the platelet metabolic and functional responses between PA performed with Haemonetics and LRPA performed with Trima Accel cell separator.MethodsThe qualities of platelets collected through PA and LRPA were evaluated in terms of visual appearance, morphology, platelet-aggregation changes, metabolic activities, and bacterium-screening test during 5-day storage. Statistical analyses included two-sample t-test and generalised estimating equation(GEE) method.ResultsDuring 5-day storage in LRPA, residual leucocytes were all <1.0×10⁶, and the parameters of platelet function were as follows: platelet aggregated to agonists such as adenosine 5′-diphosphate (ADP) and collagen, and the extent of shape change and pO₂ showed no statistically significant difference between PA and LRPA. The hypotonic shock reaction (HSR) on days 0, 1, and 3 were significantly higher in LRPA than in PA (71.78±6.92 vs. 64.10±7.42; P=0.002; 71.53±8.98 vs. 62.96±9.84; P=0.007; 68.05±7.28 vs. 57.76±6.80; P<0.0001, respectively). Values of mean platelet volume (MPV) were statistically larger in PA than in LRPA on days 0, 1, and 3. On day 5, the swirling score was higher in LRPA than in PA. The mean lactate levels had no statistically significant difference between PA and LRPA. Moreover, no growth was observed through bacterium-screening test conducted on 40 samples.ConclusionComparison of LRPA and PA products collected from the Trima Accel and Haemonetics automated blood-collection systems, respectively, revealed that both products possessed good platelet qualities even though additional processes are needed to reduce leucocytes. Furthermore, investigating the outcomes of other apheresis instruments with focus on the safety of donors, products, and recipients is necessary.     

睾酮对低氧小鼠红细胞比容和血清促红细胞生成素的影响

为了观察性激素对红细胞生成的作用,应用低压舱(0.42atm,22h/d)分别给小鼠注射人重组促红细胞生成素(rhEPO)、睾酮、皮质醇,检测红细胞比容(Hct)和血清促红细胞生成素(sEPO)的变化。结果表明:低氧6d后,各组sEPO均显著升高(P<0.05);注射rhEPO或睾酮组的Hct显著增加(P<0.05);注射rhEPO或睾酮组的Hct显著增加(P<0.05),而注射皮质醇组Hct改变不显著(P>0.05)。     

Mega-Liposuction: Analysis of 1520 Patients

Fifteen hundred and twenty cases of liposuction/liposculpture were performed at Dr. M. Erfan & Bagedo Hospitals and King Abdulaziz University Hospital in Jeddah from January 1983 to December 1994. These cases were mostly females. The age group was from 16–65 years. Multiple procedures were performed in 11.68% of these cases. The change in hemoglobin and the hematocrit ratio pre- and post-operatively, and the incidence of complications, were studied. The percentage of surface area operated upon rather than the amount of fat removed was the most important relevant factor.     

Restrictive Transfusion Practice During Extracorporeal Membrane Oxygenation Therapy for Severe Acute Respiratory Distress Syndrome

Recommendations concerning the management of hemoglobin levels and hematocrit in patients on extracorporeal membrane oxygenation (ECMO) still advise maintenance of a normal hematocrit. In contrast, current transfusion guidelines for critically ill patients support restrictive transfusion practice. We report on a series of patients receiving venovenous ECMO (vvECMO) for acute respiratory distress syndrome (ARDS) treated according to the restrictive transfusion regimen recommended for critically ill patients. We retrospectively analyzed 18 patients receiving vvECMO due to severe ARDS. Hemoglobin concentrations were kept between 7 and 9 g/dL with a transfusion trigger at 7 g/dL or when physiological transfusion triggers were apparent. We assessed baseline data, hospital mortality, time on ECMO, hemoglobin levels, hematocrit, quantities of packed red blood cells received, and lactate concentrations and compared survivors and nonsurvivors. The overall mortality of all patients on vvECMO was 38.9%. Mean hemoglobin concentration over all patients and ECMO days was 8.30 ± 0.51 g/dL, and hematocrit was 0.25 ± 0.01, with no difference between survivors and nonsurvivors. Mean numbers of given PRBCs showed a trend towards higher quantities in the group of nonsurvivors, but the difference was not significant (1.97 ± 1.47 vs. 0.96 ± 0.76 units; P = 0.07). Mean lactate clearance from the first to the third day was 45.4 ± 28.3%, with no significant difference between survivors and nonsurvivors (P = 0.19). In our cohort of patients treated with ECMO due to severe ARDS, the application of a restrictive transfusion protocol did not result in an increased mortality. Safety and feasibility of the application of a restrictive transfusion protocol in patients on ECMO must further be evaluated in randomized controlled trials.