van den Heuvel Ingeborg, Vlasselaers Dirk, Wouters Pieter J, Milants Ilse, Ellger Björn, Vanhorebeek Ilse, Van den Berghe Greet
Department of Intensive Care Medicine, Catholic University of Leuven, Belgium.
Pediatr Crit Care Med. 2009 Jan;10(1):66-70. doi: 10.1097/PCC.0b013e31819374b0.
Serial postoperative blood lactate (BL) concentrations have been shown to predict outcome of children after congenital heart surgery (CHS), and interventions aimed at lowering lactate can improve the outcome of these children. The cumulative blood loss for diagnostic purposes, such as repetitive arterial blood sampling in the intensive care unit, contributes, especially in small children, to anemia. Techniques to limit blood loss can therefore be of use. Microdialysis is a technique to monitor tissue chemistry in various clinical settings, and we hypothesized that it may be a valuable alternative for frequent blood sampling to monitor lactate in children after CHS.
Fifteen children with a mean age of 40 months (range, 4-118 months) were prospectively enrolled after CHS. A CMA double lumen microdialysis catheter was inserted into the subcutaneous adipose tissue of the abdominal wall and infused with an isotone mannitol 5% solution at 1 microL/min via the inlet tubing. Microdialysate fluid was collected every hour for 48 hrs and stored at -80 degrees C for lactate determination (interstitial fluid lactate, IFL). Every hour arterial blood was taken for lactate determination. Individual profiles, correlation coefficient, and Bland-Altman analysis were used to compare BL and IFL results.
There were no complications with the microdialysis technique. All patients were discharged alive from hospital. Six hundred twenty paired samples were analyzed. Mean recovery of microdialysate fluid was 84%. Median (interquartile range) was 0.95 (0.70-1.15) mmol/L for BL and 1.13 (0.86-1.48) mmol/L for IFL (p < 0.0001). Individual profiles showed that IFL follows changes in BL in some, but not all children. With this study, we could not explain this discrepancy. The correlation between BL and IFL was poor (r = .77 (p < 0.0001) r = .59). Bland-Altman analysis confirmed the insufficient performance of the current microdialysis-based procedure compared with BL.
Serial lactate measurements in microdialysis fluid of subcutaneous adipose tissue are feasible, but cannot be used as a reliable interchangeable method for plasma lactate analysis in children after CHS at this time. Whether this technique has its own place in the assessment of the overall hemodynamic status and tissue perfusion in children after CHS needs to be addressed in future studies.
术后连续血乳酸（BL）浓度已被证明可预测先天性心脏病手术（CHS）后儿童的预后，旨在降低乳酸的干预措施可改善这些儿童的预后。用于诊断目的的累积失血量，如在重症监护病房重复进行动脉血采样，尤其在幼儿中会导致贫血。因此，限制失血的技术可能会有用。微透析是一种在各种临床环境中监测组织化学的技术，我们假设它可能是CHS后儿童频繁采血监测乳酸的一种有价值的替代方法。
15名平均年龄40个月（范围4 - 118个月）的儿童在CHS后被前瞻性纳入研究。将一根CMA双腔微透析导管插入腹壁皮下脂肪组织，并通过进液管以1微升/分钟的速度注入5%的等渗甘露醇溶液。每小时收集微透析液48小时，并储存在-80℃用于乳酸测定（组织间液乳酸，IFL）。每小时采集动脉血用于乳酸测定。使用个体曲线、相关系数和Bland - Altman分析来比较BL和IFL结果。
微透析技术无并发症发生。所有患者均存活出院。分析了620对样本。微透析液的平均回收率为84%。BL的中位数（四分位间距）为0.95（0.70 - 1.15）毫摩尔/升，IFL为1.13（0.86 - 1.48）毫摩尔/升（p < 0.0001）。个体曲线显示，在部分但并非所有儿童中，IFL随BL变化。通过本研究，我们无法解释这种差异。BL与IFL之间的相关性较差（r = 0.77（p < 0.0001），r = 0.59）。Bland - Altman分析证实，与BL相比，当前基于微透析的方法性能不足。
皮下脂肪组织微透析液中连续乳酸测量是可行的，但目前不能用作CHS后儿童血浆乳酸分析的可靠替代方法。该技术在CHS后儿童整体血流动力学状态和组织灌注评估中是否有自身的作用，有待未来研究探讨。
