Moist Louise M, Hemmelgarn Brenda R, Lok Charmaine E
London Health Science Centre-Victoria Hospital, 800 Commissioners Road E, Room A2-338, London, Ontario, Canada, N6A 5W9.
Clin J Am Soc Nephrol. 2006 Sep;1(5):965-71. doi: 10.2215/CJN.01090306. Epub 2006 Jun 28.
Central venous catheter dysfunction is a frequent problem and often is defined as a blood flow <300 ml/min. This prospective, cross-sectional study included 259 patients and examined the relationship between catheter blood flow and dialysis adequacy as measured by urea reduction ratio (URR), single pool urea kinetics, and online effective ionic dialysance clearance. Dialysis adequacy at blood flow rates of <300, <275, and <250 ml/min; sensitivity; specificity; and positive and negative predictive values were calculated. Mean blood flow was 352 ml/min (SD +/- 48.8). Mean blood flow <300 ml/min occurred in 10.5% of the patients, and only 26% had a URR of <65%. Maximum blood flows <300 ml/min occurred in 6.9% of patients, and only 22.2% had URR <65%. The positive predictive value of mean blood flow of <300 and <275 ml/min to predict a URR <65% was 22 and 40%, respectively. Using receiver operator characteristic curves, the area under the curve was not significantly different for blood flows of 300, 275, or 250 ml/min. This study indicates that mean blood flows <300 ml/min are not commonly associated with dialysis inadequacy. Setting a single blood flow cut point of <300 ml/min to define the need for intervention will result in a significant number of unnecessary interventions. There is a need to reexamine the definition of catheter dysfunction and expand the definition beyond blood flow rates.
中心静脉导管功能障碍是一个常见问题，通常被定义为血流量<300 ml/分钟。这项前瞻性横断面研究纳入了259例患者，研究了导管血流量与通过尿素清除率（URR）、单池尿素动力学和在线有效离子透析清除率衡量的透析充分性之间的关系。计算了血流量<300、<275和<250 ml/分钟时的透析充分性、敏感性、特异性以及阳性和阴性预测值。平均血流量为352 ml/分钟（标准差±48.8）。10.5%的患者平均血流量<300 ml/分钟，只有26%的患者URR<65%。6.9%的患者最大血流量<300 ml/分钟，只有22.2%的患者URR<65%。平均血流量<300和<275 ml/分钟预测URR<65%的阳性预测值分别为22%和40%。使用受试者工作特征曲线，300、275或250 ml/分钟血流量的曲线下面积无显著差异。这项研究表明，平均血流量<300 ml/分钟通常与透析不充分无关。设定<300 ml/分钟的单一血流量切点来定义干预需求将导致大量不必要的干预。有必要重新审视导管功能障碍的定义，并将定义扩展到血流量率之外。
