Diffusing capacity: how to get it right.
Diffusing capacity: how to get it right.
复制标题
扩散能力：如何正确实现。
作者：
R. Jensen;R. Crapo
一氧化碳弥散量测试（D（LCO））是一种常用的肺功能测试，需要专业技术和对细节的关注才能获得可接受的结果。随着自动化设备和功能强大的计算机程序的出现，D（LCO）测量已迅速获得广泛的临床认可。但是执行测试有许多微妙的方面会降低其准确性和可重复性。临床医生必须确保：D（LCO）仪器校准正确;吸气量至少为之前测量的最大肺活量的90%;患者在2秒内快速、平稳吸气;屏气时间为9-11秒;屏气没有紧张（无Valsalva或Müller动作）;呼气快速平稳;从呼气的正确部分获得代表性气体样本;并且D（LCO）测试之间至少间隔5分钟。应进行至少2次但不超过5次D（LCO）试验，当2次试验彼此相差10%或3个D（LCO）单位（mL CO/min/mm Hg）时，试验完成。报告的D（LCO）值是符合再现性标准的前2次测试的平均值，但如果进行了5次测试，但没有2次测试符合再现性标准，则报告的值是具有最高吸气量的2次测试的平均值。这些质量控制将帮助实验室实现一致的高D（LCO）精度。
The carbon monoxide diffusing capacity test (D(LCO)) is a commonly performed pulmonary function test that requires technical expertise and attention to detail to get acceptable results. With the advent of automated devices and powerful computer programs, D(LCO) measurement has rapidly gained wide clinical acceptance. But there are many subtle aspects to performing the test that can diminish its accuracy and repeatability. The clinician must ensure: that the D(LCO) instrument is correctly calibrated; that inhalation is least 90% of the largest previously measured vital capacity; that the patient executes a quick, smooth inhalation within 2 seconds; that the breath-hold is 9-11 seconds; that the breath-hold is without straining (no Valsalva or Müller maneuvers); that exhalation is quick and smooth; that a representative gas sample is obtained from the correct portion of the exhalation; and that at least 5 minutes elapse between D(LCO) tests. At least 2 but no more than 5 D(LCO) tests should be conducted, and testing is complete when 2 tests are within 10% or 3 D(LCO) units (mL CO/min/mm Hg) of each other. The reported D(LCO) value is the average of the first 2 tests that meet the reproducibility criteria, but if 5 tests are performed and no 2 meet the reproducibility criteria, the reported value is the average of the 2 tests with the highest inspiratory volumes. These quality controls will help laboratories achieve consistent high D(LCO) accuracy.