Haematocrit and plasma volume during induction of anaesthesia
Haematocrit and plasma volume during induction of anaesthesia
复制标题
麻醉诱导期间的血细胞比容和血浆容量
DOI：
10.1111/aas.13202
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发表时间：
2018
影响因子：
2.1
通讯作者：
K. Hirota
中科院分区：
文献类型：
--
作者：
J. Saito;K. Hirota
致编辑：我们怀着极大的兴趣阅读了damsamen等人关于血压依赖性红细胞压积（Hct）和血浆容量变化的报告。作者评估了在无液体麻醉诱导期间输注去甲肾上腺素对Hct和血浆容量（PV）的影响。他们发现，在诱导过程中维持诱导前的血压水平可以抑制Hct和PV的变化。我们重新评估了我们的两项临床研究，证实了在不麻醉（n = 37）或以0.05 μg/kg/min持续输注苯肾上腺素（n = 15）诱导麻醉时类似的现象。Hct分别下降了9.8±4.6%和2.9±2.7% (P < 0.01，图1A)，对应于PV分别增加了18.2±10.2%和5.0±4.4% （P < 0.001）。此外，未使用苯肾上腺素的小鼠白细胞（WBC）和血小板的变化（- 1333±928/μL和- 2.4±2.5 × 104/μL）显著大于使用苯肾上腺素的小鼠白细胞（- 107±628/μL和1.4±0.15 × 104/μL, P < 0.001）（图1B， C）。damsamen等人假设PV的增加可能是由于“自身输血”。虽然PV的变化是用Hct的标准公式计算的，但Hct不仅受PV的影响，还会受到其他因素的影响。众所周知，脾脏对循环血细胞计数的变化具有重要作用。O'Brien等人发现，在使用几种麻醉药物后，可以观察到脾肿大。此外，Ojiri等人报道，血管扩张剂输注脾动脉增加脾直径，脾静脉红细胞浓度立即降低，随后全身红细胞减少，而α - 1肾上腺素刺激剂（包括去甲肾上腺素和苯肾上腺素）输注脾直径降低，脾静脉红细胞浓度立即增加，随后全身红细胞增加。这些结果提示麻醉诱导时Hct和PV的变化可能主要是由于脾收缩和充血所致。虽然在麻醉诱导过程中PV可能增加，但用标准公式计算PV的变化可能被高估。
To the Editor, With great interest, we read the report regarding blood pressure‐ dependent changes in haematocrit (Hct) and plasma volume by Damén et al The authors evaluated the effect of norepinephrine infusion on Hct and plasma volume (PV) during induction of anaesthesia without fluid administration. They revealed that maintaining pre‐induction levels of blood pressure during the induction suppressed changes in Hct and PV. We have re‐assessed our two clinical studies and confirmed similar phenomenon during induction of anaesthesia without (n = 37) or with continuous infusion of phenylephrine at 0.05 μg/kg/min (n = 15). The Hct decreased by 9.8 ± 4.6% and 2.9 ± 2.7% without and with phenylephrine (P < 0.01, Figure 1A), which corresponds to increase in PV by 18.2 ± 10.2% and 5.0 ± 4.4% (P < 0.001), respectively. In addition, changes in white blood cells (WBC) and platelets without phenylephrine (−1333 ± 928/μL and −2.4 ± 2.5 × 104/μL) were significantly larger than those (−107 ± 628/μL and 1.4 ± 0.15 × 104/μL, P < 0.001) with phenylephrine respectively (Figure 1B, C). Damén et al hypothesised that increases in PV could be due to “autotransfusion”. Although changes in PV were calculated with standard formula using Hct, The Hct can be affected by not only PV but also other factors. It is well known that the spleen has important role for changes in circulating blood cell counts. O'Brien et al found that splenic enlargement is observed after administration of several anaesthetic drugs. In addition, Ojiri et al reported that vasodilator infusion into splenic artery increased splenic diameter with immediate reductions in splenic venous concentrations of red blood cell (RBC) followed by reductions in systemic RBC whilst α1 adrenoceptor stimulator including noradrenaline and phenylephrine infusions decreases in splenic diameter with immediate increases in splenic venous concentrations of RBC followed by increases in systemic RBC. These results suggest that changes in Hct and PV during induction of anaesthesia may be mainly due to splenic contraction and congestion. Although PV may increase during induction of anaesthesia, changes in PV calculated with standard formula could be overestimated.