Booth John, Pinney Jennifer, Davenport Andrew
Center for Nephrology, Royal Free Hospital, London, UK.
Int J Artif Organs. 2010 Dec;33(12):900-5.
Intradialytic hypotension remains the commonest complication for outpatient hemodialysis. The majority of relative blood volume (RBV) monitoring techniques monitor changes in hematocrit. As hematocrit can potentially be affected by changes in red cell size and hemolysis we studied the change in red blood cell size (MCV) during dialysis and hemolysis.
MCV was prospectively measured in 176 stable regular adult hemodialysis outpatients (56% male, 27.8% diabetic, mean age 59.5 ±16.2 years) dialyzing against a range of dialysate sodiums (136-145 mmol/L), with cooled dialysate (35-36°C), containing 1 g/L glucose, with constant ultrafiltration profiles. Red cell fragmentation was studied in 41 of the cohort.
Logistical regression analysis showed that the absolute change in MCV was related to the change in hematocrit (F=4.92, β=0.111, p=0.031), and inversely with red cell shrinkage associated with predialysis osmolality (F=5.06, β=0.83, p=0.029), and dialysate sodium (F=4.7, β=0.34, p=0.035). There was no significant increase in red cell fragments during the dialysis sessions.
Indirect assessment of RBV based upon the relative change in hematocrit, depends not only upon the change in plasma water and red blood cell numbers, but also upon MCV. Changes in MCV may theoretically lead to potential effects on RBV measurements.
透析中低血压仍然是门诊血液透析最常见的并发症。大多数相对血容量（RBV）监测技术监测血细胞比容的变化。由于血细胞比容可能会受到红细胞大小和溶血变化的潜在影响，我们研究了透析和溶血过程中红细胞大小（平均红细胞体积，MCV）的变化。
前瞻性地测量了176例稳定的成年规律血液透析门诊患者（男性占56%，糖尿病患者占27.8%，平均年龄59.5±16.2岁）的MCV，这些患者使用一系列不同钠浓度（136 - 145 mmol/L）的透析液、冷却的透析液（35 - 36°C）、含1 g/L葡萄糖且超滤曲线恒定的透析液进行透析。对该队列中的41例患者研究了红细胞碎片情况。
逻辑回归分析显示，MCV的绝对变化与血细胞比容的变化相关（F = 4.92，β = 0.111，p = 0.031），并且与透析前渗透压相关的红细胞收缩呈负相关（F = 5.06，β = 0.83，p = 0.029），还与透析液钠浓度呈负相关（F = 4.7，β = 0.34，p = 0.035）。透析过程中红细胞碎片没有显著增加。
基于血细胞比容相对变化对RBV进行的间接评估，不仅取决于血浆水量和红细胞数量的变化，还取决于MCV。MCV的变化理论上可能会对RBV测量产生潜在影响。
