Department of Geriatric Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
J Neuroimaging. 2011 Oct;21(4):340-7. doi: 10.1111/j.1552-6569.2010.00517.x. Epub 2011 Jan 13.
The breath hold maneuver is a convenient and frequently used method to assess cerebrovascular reactivity (CR). This study aimed to assess feasibility and reproducibility of this method in healthy older persons.
Twenty-five healthy volunteers, aged 75 (SD 4) years, performed 2 consecutive breath holds after careful instruction. Blood pressure (BP-Finapres), cerebral blood flow velocity (CBFV-Transcranial Doppler), and end-tidal CO(2) (capnography) were measured continuously. As reference standard, CR was determined by hyperventilation and CO(2) -inhalation. These measurements were repeated after 3 months in 11 randomly selected subjects.
Despite apparent compliance with instructions during performance of breath holding, only 29 of the 50 breath holds (58%) had been accurately executed, which was identified only from BP and end-tidal CO(2) measurements. Incorrect breath holds led to underestimation of CR. For valid breath holds, reproducibility was comparable to the reference method (coefficient of variation 19.4% and 17.6%, respectively).
The number of inaccurate breath holds was unacceptably high, moreover, these could not be identified from CBFV registrations alone. Therefore, reports of CR based on breath holds in older subjects without coregistration of BP and either end-tidal CO(2) or chest-expansion should no longer be acceptable.
屏气试验是一种方便且常用的评估脑血管反应性（CVR）的方法。本研究旨在评估该方法在健康老年人中的可行性和可重复性。
25 名健康志愿者，年龄 75（SD 4）岁，在经过仔细指导后进行了 2 次连续屏气。连续测量血压（Finapres）、脑血流速度（经颅多普勒）和呼气末二氧化碳（二氧化碳描记法）。作为参考标准，通过过度通气和 CO2 吸入来确定 CVR。在 11 名随机选择的受试者中，3 个月后重复这些测量。
尽管在进行屏气试验时明显遵守了指导，但只有 50 次屏气中的 29 次（58%）是准确执行的，这只能从血压和呼气末二氧化碳测量中确定。不准确的屏气会导致 CVR 的低估。对于有效的屏气，其可重复性与参考方法相当（变异系数分别为 19.4%和 17.6%）。
不准确的屏气次数高得令人无法接受，而且这些屏气仅凭 CBFV 记录无法识别。因此，对于没有血压和呼气末二氧化碳或胸式呼吸同步记录的老年受试者，基于屏气的 CVR 报告不应再被接受。
