Sorbonne Universités, UPMC Univ Paris 06, INSERM, UMRS1158 Neurophysiologie respiratoire expérimentale et clinique, Paris, France.
Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Service de Pneumologie et Réanimation Médicale (Département 'R3S'), AP-HP, Paris, France.
Thorax. 2017 Mar;72(3):230-235. doi: 10.1136/thoraxjnl-2016-208544. Epub 2016 Aug 9.
Dyspnoea is a threatening sensation of respiratory discomfort that presents many similarities with pain. Experimental dyspnoea in healthy subjects induces analgesia. This 'dyspnoea-pain counter-irritation' could, in reverse, imply that relieving dyspnoea in patients with chronic respiratory diseases would lower their pain thresholds.
We first determined pressure pain thresholds in 25 healthy volunteers (22-31 years; 13 men; handheld algometer), during unloaded breathing (BASELINE) and during inspiratory threshold loading (ITL). Two levels of loading were used, adjusted to induce dyspnoea self-rated at 60% or 80% of a 10 cm visual analogue scale (ITL6 and ITL8). 18 patients with chronic respiratory failure due to amyotrophic lateral sclerosis (ALS) were then studied during unassisted breathing and after 30 and 60 min of non-invasive ventilation-NIV30 and NIV60-(same dyspnoea evaluation).
In healthy volunteers, pressure pain thresholds increased significantly in the deltoid during ITL6 (p<0.05) and ITL8 (p<0.05) and in the trapezius during ITL8 (p<0.05), validating the use of pressure pain thresholds to study dyspnoea-pain counter-irritation. In patients with ALS, the pressure pain thresholds measured in the deltoid during unassisted breathing decreased by a median of 24.5%-33.0% of baseline during NIV30 and NIV60 (p<0.05).
Relieving dyspnoea by NIV in patients with ALS having respiratory failure is associated with decreased pressure pain thresholds. Clinical implications have yet to be determined, but this observation suggests that patients with ALS could become more susceptible to pain after the institution of NIV, hence the need for reinforced attention towards potentially painful diagnostic and therapeutic interventions.
呼吸困难是一种威胁性的呼吸不适感觉，与疼痛有许多相似之处。在健康受试者中进行的实验性呼吸困难会引起镇痛。这种“呼吸困难-疼痛对抗刺激”反过来可能意味着，缓解慢性呼吸系统疾病患者的呼吸困难会降低他们的疼痛阈值。
我们首先在 25 名健康志愿者（22-31 岁；13 名男性；手持压痛计）中确定了压力疼痛阈值，分别在无负荷呼吸（基线）和吸气阈负荷（ITL）期间。使用两种负荷水平，调整至引起自我报告的呼吸困难程度为 10cm 视觉模拟量表的 60%或 80%（ITL6 和 ITL8）。然后，在自主呼吸期间以及接受无创通气 30 分钟（NIV30）和 60 分钟（NIV60）后，对 18 名因肌萎缩侧索硬化症（ALS）导致慢性呼吸衰竭的患者进行了研究（使用相同的呼吸困难评估）。
在健康志愿者中，在 ITL6（p<0.05）和 ITL8（p<0.05）期间三角肌的压力疼痛阈值显着增加，在 ITL8 期间斜方肌的压力疼痛阈值也显着增加（p<0.05），验证了使用压力疼痛阈值来研究呼吸困难-疼痛对抗刺激的有效性。在 ALS 患者中，在自主呼吸期间三角肌测量的压力疼痛阈值在 NIV30 和 NIV60 期间降低了基线的中位数 24.5%-33.0%（p<0.05）。
在患有呼吸衰竭的 ALS 患者中，通过 NIV 缓解呼吸困难与压力疼痛阈值降低有关。临床意义尚未确定，但这一观察结果表明，在开始 NIV 后，ALS 患者可能更容易受到疼痛的影响，因此需要加强对潜在疼痛诊断和治疗干预的关注。
