RT Journal Article SR Electronic T1 Relieving dyspnoea by non-invasive ventilation decreases pain thresholds in amyotrophic lateral sclerosis JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 230 OP 235 DO 10.1136/thoraxjnl-2016-208544 VO 72 IS 3 A1 Laurence Dangers A1 Louis Laviolette A1 Marjolaine Georges A1 Jésus Gonzalez-Bermejo A1 Isabelle Rivals A1 Thomas Similowski A1 Capucine Morelot-Panzini YR 2017 UL http://thorax.bmj.com/content/72/3/230.abstract AB Background 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.Methods 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).Results 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).Conclusion 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.