Depner T A, Krivitski N M
Division of Nephrology, University of California, Davis, Sacramento 95817, USA.
ASAIO J. 1995 Jul-Sep;41(3):M745-9. doi: 10.1097/00002480-199507000-00112.
Blood flow is a fundamental property of the hemodialysis access device. Periodic monitoring of flow could be useful for detection of impending access failure and prevention of underdialysis, but simple measurements of access flow during hemodialysis are not currently available. Flow in peripheral arteriovenous fistulas and grafts was examined using an indicator dilution technique while the patient's blood lines were reversed. The indicator was a bolus of normal saline detected by an ultrasound flow sensor clamped onto the patient's blood line. The ultrasound sensor measured blood flow in the tubing using an established transit-time method and simultaneously detected saline dilution of the blood from changes in the average cross sectional velocity of an ultrasound beam that illuminated the blood flowing through the tubing. Access flow was measured 110 times in 25 patients, 16 with loop grafts and 9 with native fistulas. Measured access flow ranged from 125 to 2860 ml/min. The mean error of duplicate measurements within patients was 5.0 +/- 3.8%. To assess the adequacy of saline mixing with the blood, access flow was measured at three dialyzer blood flow rates. In paired studies, no significant difference was observed in access flow measured at two lower dialyzer blood flow rates when compared to flow measured at 350 ml/min. A comparison with access flow measured by a duplex color Doppler technique in seven patients gave a mean error of 9.2 +/- 7.2% in paired studies. These data show that blood flow in peripheral arteriovenous grafts and fistulas can be measured accurately during hemodialysis using ultrasound velocity dilution.
血流量是血液透析通路装置的一项基本特性。定期监测血流量有助于检测即将发生的通路故障并预防透析不充分，但目前尚无法在血液透析期间对通路血流量进行简单测量。在患者的血液管路反转时，使用指示剂稀释技术检测了外周动静脉内瘘和移植物中的血流。指示剂是通过夹在患者血路上的超声流量传感器检测到的生理盐水团注。超声传感器采用既定的渡越时间方法测量管路中的血流量，并同时通过照射流经管路的血液的超声束平均横截面速度的变化来检测血液中的生理盐水稀释情况。对25例患者（16例使用袢形移植物，9例使用自体动静脉内瘘）的通路血流量进行了110次测量。测得的通路血流量范围为125至2860毫升/分钟。患者重复测量的平均误差为5.0±3.8%。为评估生理盐水与血液混合的充分性，在三种透析器血流量下测量了通路血流量。在配对研究中，与在350毫升/分钟时测得的血流量相比，在两种较低透析器血流量下测得的通路血流量无显著差异。在七名患者中，与采用双功彩色多普勒技术测得的通路血流量进行比较，配对研究中的平均误差为9.2±7.2%。这些数据表明，在血液透析期间，使用超声速度稀释法可准确测量外周动静脉移植物和内瘘中的血流量。
