Department of Anesthesiology and Pain Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50, Ilwon-Dong, Kangnam-Ku, Seoul, 135-710 Korea.
Anesth Analg. 2011 Apr;112(4):924-30. doi: 10.1213/ANE.0b013e31820d93d8. Epub 2011 Feb 2.
Movement of the cerebrospinal fluid (CSF) is one of the most important factors in determining the intrathecal spread of isobaric spinal anesthetics. Preanesthetic administration of either crystalloid or colloid immediately before spinal anesthesia (preload) may result in different CSF pulsatile movement because of their different physical properties. We examined whether preload of crystalloid versus colloid may have different effects on the intrathecal spread of isobaric spinal anesthetics as a result of their different CSF dynamics regarding its pulsatile movement.
In a clinical study of isobaric spinal anesthesia, patients were allocated into 1 of 2 groups according to preload with either crystalloid (n = 30) or colloid (n = 30) before spinal anesthesia with 0.5 isobaric tetracaine. The pulsatile movements of CSF at the L2-3 intervertebral space and midportion of the aqueduct of Sylvius were also examined by magnetic resonance images in healthy volunteers (n = 23) at 0, 30, and 60 minutes after administering either crystalloid or colloid.
In the clinical study, the time to reach the peak sensory block level was delayed significantly in the crystalloid preload group (27.2 ± 17.8 minutes; P < 0.01) compared with the colloid preload group (13.9 ± 7.0 minutes). The median sensory block levels of the crystalloid preload group at 15 minutes (T10, P < 0.05) and 20 minutes (T9.5, P < 0.05) were significantly lower than those (T8, T7, respectively) of the colloid preload group. In the magnetic resonance imaging study, cranially directed CSF pulsatile movement decreased significantly at the L2-3 intervertebral intrathecal space at 30 minutes after crystalloid administration, but not after colloid administration. The CSF production rate significantly increased at 30 minutes (637 μL/min, P < 0.05) after crystalloid preload compared with the baseline measurement (448 μL/min), and then slightly decreased (609 μL/min) at 60 minutes. In the colloid preload group, the CSF production rate was not statistically significant compared with the baseline measurement (464, 512, and 542 μL/min at baseline, 30, and 60 minutes, respectively).
Compared with a colloid preload, which may be comparable to the no-preload condition, crystalloid preload prolonged the time to reach the peak sensory block level in isobaric spinal anesthesia, which might have been caused by a significant decrease in CSF pulsatile movement. This attenuated CSF pulsatile movement in the crystalloid preload group might have resulted from significant increases of CSF production.
脑脊液（CSF）的流动是决定等比重椎管内麻醉中药物向蛛网膜下腔扩散的最重要因素之一。在椎管内麻醉前即刻给予晶体液或胶体液（预负荷）可能会因不同的物理特性而导致不同的 CSF 搏动性运动。我们研究了晶体液与胶体液的预负荷是否会由于其 CSF 动力学中搏动性运动的不同而对等比重椎管内麻醉中药物的向蛛网膜下腔扩散产生不同的影响。
在一项等比重椎管内麻醉的临床研究中，根据麻醉前用晶体液（n=30）或胶体液（n=30）预负荷，将患者分为 2 组。在 0.5 等比重的四卡因椎管内麻醉前，通过磁共振成像（MRI）还检测了健康志愿者（n=23）L2-3 椎间空间和 Sylvius 导水管中段的 CSF 搏动性运动。在给予晶体液或胶体液 0、30 和 60 分钟后，也分别进行了检测。
在临床研究中，与胶体预负荷组（13.9±7.0 分钟；P＜0.01）相比，晶体预负荷组达到感觉阻滞最高水平的时间显著延迟（27.2±17.8 分钟）。晶体预负荷组在 15 分钟（T10，P＜0.05）和 20 分钟（T9.5，P＜0.05）的感觉阻滞水平中位数明显低于胶体预负荷组（T8、T7）。在 MRI 研究中，晶体液给药 30 分钟后，L2-3 椎间蛛网膜下腔内的 CSF 搏动性运动向头侧显著减少，但胶体液给药后无此变化。与基线测量值（448μL/min）相比，晶体预负荷后 30 分钟（637μL/min，P＜0.05）的 CSF 生成率显著增加，60 分钟时略有下降（609μL/min）。胶体预负荷组与基线测量值相比，CSF 生成率无统计学意义（分别为基线、30 和 60 分钟时的 464、512 和 542μL/min）。
与胶体预负荷相比，晶体液预负荷可能会导致 CSF 搏动性运动明显减少，从而延长等比重椎管内麻醉中达到感觉阻滞最高水平的时间，这可能是由于 CSF 搏动性运动显著减少所致。晶体预负荷组 CSF 搏动性运动减弱可能是由于 CSF 生成量显著增加所致。
