Background

Deterioration of vital capacity (VC) in amyotrophic lateral sclerosis (ALS) signifies disease progression and indicates need for non-invasive ventilation. Weak facial muscles consequent to ALS, with resulting poor mouth seal, may interfere with the accuracy of VC measurements.

Objectives

To determine whether different interfaces affect VC measurements in ALS patients and whether the interface yielding the largest VC produces an even higher VC when re-measured after one week (learning effect). To explore the relationship between optimal interface VC and sniff nasal pressure (SNIP), a measurement of global inspiratory muscle strength.

Methods

Thirty-five patients (17 bulbar and 18 spinal ALS) were studied. Three interfaces (rigid-cylindrical, flanged, oronasal mask) were tested. One week after the first visit, VC was recorded using the optimal interface. SNIP recordings were also obtained.

Results

In the bulbar ALS group, median (interquartile range) VC with the flanged mouthpiece was 8.4% (3.9–15.5) larger than with the cylindrical mouthpiece (p < 0.001). VC values with oronasal mask were intermediate to VC with the other two interfaces. In spinal ALS, flanged mouthpiece VC was 4.6% (2.3–7.5) larger than with oronasal mask (p < 0.0006). The latter was 4.5% (0.6–5.2) smaller than with the cylindrical mouthpiece (p = 0.002). In both groups, VC during the second visit was greater than during the first visit (p < 0.025). SNIPs were logarithmically related to VC values recorded with the flanged mouthpiece.

Conclusion

A flanged mouthpiece yields the largest values of VC in patients with bulbar and spinal ALS.

中文翻译：

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测量肌萎缩侧索硬化的肺活量：界面和再现性的影响

背景

肌萎缩侧索硬化 (ALS) 肺活量 (VC) 的恶化表明疾病进展并表明需要无创通气。ALS 导致的面部肌肉无力，导致口腔密封不良，可能会干扰 VC 测量的准确性。

目标

确定不同的界面是否影响 ALS 患者的 VC 测量，以及产生最大 VC 的界面在一周后重新测量时是否会产生更高的 VC（学习效果）。探索最佳界面 VC 与鼻嗅压 (SNIP) 之间的关系，SNIP 是整体吸气肌力的测量值。

方法

研究了 35 名患者（17 名延髓 ALS 和 18 名脊柱 ALS）。测试了三个界面（刚性圆柱面罩、法兰面罩、口鼻面罩）。第一次访问后一周，使用最佳界面记录VC。还获得了 SNIP 录音。

结果

在延髓 ALS 组中，带凸缘咬嘴的中位（四分位距）VC 比带圆柱形咬嘴的 VC 大 8.4% (3.9-15.5)（p < 0.001）。口鼻面罩的 VC 值介于其他两个界面的 VC 之间。在脊柱 ALS 中，带法兰的咬嘴 VC 比使用口鼻面罩时大 4.6% (2.3-7.5) (p < 0.0006)。后者比圆柱形吹嘴小 4.5% (0.6-5.2) (p = 0.002)。在两组中，第二次访问期间的 VC 都大于第一次访问期间 (p < 0.025)。SNIP 与使用带法兰的咬嘴记录的 VC 值呈对数相关。

结论

在延髓和脊柱 ALS 患者中，带法兰的咬嘴产生最大的 VC 值。