Porter J M, Swain I D, Shakespeare P G
Odstock Hospital, Salisbury, Wiltshire, UK.
J Biomed Eng. 1987 Oct;9(4):367-73. doi: 10.1016/0141-5425(87)90086-0.
The range of pulsatile arm and finger blood flow, measured by electrical impedance plethysmography, has been investigated in a hospital ward. The range of absolute blood flows, in ml min-1, was found to be too wide to be used as a standard for identifying single blood flow readings as being abnormal. A blood flow ratio was calculated by dividing the blood flow in the right forearm or middle finger by the blood flow in the left forearm or middle finger. This ratio was found to have a clearly defined range. A blood flow in a unilaterally injured or otherwise abnormal arm or finger was considered to be significantly altered if the blood flow ratio fell outside the previously defined normal range. The diagnosis of significantly altered arm and finger blood flow from abnormalities in the blood flow ratio was tested in a series of experiments, in which artificial changes in upper limb flow were created by high elevation of the right hand. The ratio was measured in 11 patients with unilateral upper limb injuries and in 3 patients who required an urgent assessment of the upper limb circulation. Abnormalities in the ratio were identified in 12 out of 18 subjects after high elevation of the hand and in 8 out of the 14 patients.
在医院病房中，通过电阻抗体积描记法测量了搏动性手臂和手指的血流范围。发现以毫升每分钟为单位的绝对血流范围太宽，无法用作识别单个血流读数是否异常的标准。通过将右前臂或中指的血流除以左前臂或中指的血流来计算血流比率。发现该比率有明确界定的范围。如果血流比率超出先前定义的正常范围，则认为单侧受伤或以其他方式异常的手臂或手指中的血流有显著改变。在一系列实验中测试了根据血流比率异常诊断手臂和手指血流显著改变的方法，在这些实验中，通过将右手高高举起人为改变上肢血流。对11例单侧上肢损伤患者和3例需要紧急评估上肢循环的患者测量了该比率。在抬高手部后，18名受试者中有12名、14名患者中有8名的比率出现异常。
