Leblanc M, Fedak S, Mokris G, Paganini E P
Cleveland Clinic Foundation, Ohio 44195, USA.
Clin Nephrol. 1996 May;45(5):315-9.
The low-flow method has been shown as a reliable evaluation of access recirculation. Few data is available on temporary central catheter blood recirculation; results of 2% and 4% have been reported in subclavian, 10% in 24 cm long femoral, and 18% in 15 cm long femoral catheters, mostly in indwelling catheters for chronic hemodialysis. The purpose of this prospective study was to evaluate blood recirculation in a larger number of recently inserted temporary intravenous catheters for acute hemodialysis, comparing subclavian and femoral sites. Fifty blood recirculation measurements were performed in 38 different temporary central venous dialysis catheters inserted in thirty-one critically ill patients from medical and surgical intensive care units presenting acute renal failure supported by intermittent hemodialysis. All the catheters used were well-functioning 11.5 French dual lumen Quinton of 13.5 or 19.5 cm length. Catheters presenting mechanical dysfunction, which did not allow a blood flow rate of 300 ml/min or for which lines had to be reversed were excluded from the analysis. Access blood recirculation was measured shortly after catheter insertion according to the low flow method applied after the first 30 minutes of hemodialysis at a blood flow rate of 300 ml/min. Mean blood recirculation for the 50 measurements was 10.3 +/- 9.2%. It was significantly higher in the 26 femoral catheters than in the 24 subclavian catheters, reaching respective means of 16.1 +/- 9.1% and 4.1 +/- 3.6% (p = 0.0001). Blood recirculation rate was not different between 13.5 cm and 19.5 cm long subclavian catheters (3.0 +/- 2.6%, n = 13, versus 5.4 +/- 4.3%, n = 11, respectively), but was significantly higher in 13.5 cm long femoral catheters (22.8 +/- 9.1%, n = 9, versus 12.6 +/- 6.9%, n = 17) (p = 0.004). Blood recirculation was measured on two separate occasions in 12 catheters randomly selected (5 femoral and 7 subclavian catheters); the obtained results were reproducible with a mean difference of only 2.1 +/- 1.8% between the two measurements and a correlation of 0.96. The mean time elapsed between catheter insertion and recirculation assessment was 2.2 +/- 3.1 days and was similar for femoral and subclavian catheters. No correlation was found between the percentage of recirculation and the arterial and venous resistances recorded during dialysis session or with the time from catheter insertion. Mean urea reduction ratio (URR) for the 50 dialysis sessions was 57.8 +/- 13.0%. It was significantly higher for sessions performed with subclavian than with femoral catheters (62.5 +/- 10.9%, n = 24, versus 54.5 +/- 14.2%, n = 26) (p = 0.03). In conclusion, the expected blood recirculation in well-functioning and recently inserted temporary dialysis catheters is under 5% for subclavian, over 12% in 19.5 cm femoral, and over 22% in shorter 13.5 cm femoral catheters at a blood flow rate of 300 ml/min. The consequently reduced dialysis efficiency with femoral catheters is another factor to be considered in the choice of a site for temporary dialysis catheter insertion in acute renal failure patients, particularly when dialysis dose delivery is a priority, such as intoxication cases treated by extracorporeal therapy.
低流量法已被证明是评估通路再循环的可靠方法。关于临时中心静脉导管血液再循环的数据较少；锁骨下导管的再循环率报告为2%和4%，24厘米长的股静脉导管为10%，15厘米长的股静脉导管为18%，这些大多是慢性血液透析的留置导管。本前瞻性研究的目的是评估大量近期插入的用于急性血液透析的临时静脉导管的血液再循环情况，比较锁骨下和股静脉部位。对31例来自内科和外科重症监护病房的急性肾衰竭患者进行间歇性血液透析支持，在插入的38根不同的临时中心静脉透析导管中进行了50次血液再循环测量。所有使用的导管均为功能良好的11.5法国双腔昆顿导管，长度为13.5或19.5厘米。出现机械功能障碍、无法达到300毫升/分钟血流速度或需要更换管路的导管被排除在分析之外。在血液透析开始30分钟后，以300毫升/分钟的血流速度，根据低流量法在导管插入后不久测量通路血液再循环。50次测量的平均血液再循环率为10.3±9.2%。26根股静脉导管的再循环率显著高于24根锁骨下导管，分别为16.1±9.1%和4.1±3.6%（p = 0.0001）。13.5厘米和19.5厘米长的锁骨下导管之间的血液再循环率无差异（分别为3.0±2.6%，n = 13，和5.4±4.3%，n = 11），但13.5厘米长的股静脉导管的再循环率显著更高（22.8±9.1%，n = 9，和12.6±6.9%，n = 17）（p = 0.004）。在随机选择的12根导管（5根股静脉导管和7根锁骨下导管）上进行了两次单独的血液再循环测量；两次测量结果具有可重复性，平均差异仅为2.1±1.8%，相关性为0.96。导管插入与再循环评估之间的平均时间为2.2±3.1天，股静脉导管和锁骨下导管相似。再循环百分比与透析过程中记录的动脉和静脉阻力或与导管插入后的时间之间未发现相关性。50次透析治疗的平均尿素清除率（URR）为57.8±13.0%。锁骨下导管进行的透析治疗的URR显著高于股静脉导管（62.5±10.9%，n = 24，和54.5±14.2%，n = 26）（p = 0.03）。总之，在血流速度为300毫升/分钟时，功能良好且近期插入的临时透析导管的预期血液再循环率为：锁骨下导管低于5%，19.5厘米长的股静脉导管超过12%，较短的13.5厘米长的股静脉导管超过22%。股静脉导管导致的透析效率降低是急性肾衰竭患者选择临时透析导管插入部位时需要考虑的另一个因素，特别是在透析剂量输送至关重要的情况下，如体外治疗的中毒病例。
