The PASE Study: The Prevalence and Associations of Bendopnoea in Patients with Pneumothorax

Background: We recently established that bendopnoea (breathlessness upon bending forward) is common with pleural effusion; however, it has never been reported or investigated in patients with pneumothorax. This exploratory study investigated the prevalence and clinical relevance of bendopnoea in pneumothorax. Methods: Patients with pneumothorax of any aetiology or size were eligible. The presence of bendopnoea and time-to-bendopnoea was measured by bending the patient forward for 60 s and was assessed at baseline and post lung re-expansion. Results: Fifty patients (median age 48 years; 78% male) with primary spontaneous (48%), secondary spontaneous (24%) or iatrogenic (28%) pneumothorax were included. Pneumothorax size ranged from 7 to 99% of the hemithorax on chest radiographs. Most patients (74%) received conservative management. On a questionnaire, 48% (24/50) patients reported they experienced bendopnoea which "impacted daily life". When bent forward, 32% (16/50) developed bendopnoea within 60 s. Patients with bendopnoea reported more breathlessness than those without bendopnoea on a 100 mm Visual Analogue Scale (VAS): median 46 [Q1-Q3 = 25-54] vs. 12 [3-32] mm, respectively, p = 0.0089; median difference -23 mm (95% CI -35 to -6). Those with bendopnoea showed a signal with worse chest pain on a 100 mm VAS for pain: median 28 [13-48] vs. 10 [2-42] mm, p = 0.0528; median difference -15 mm (95% CI -27 to 0). Shorter time-to-bendopnoea (i.e., worse bendopnoea) correlated with worse breathlessness (r_s = -0.38, 95% CI -0.6 to -0.1; p = 0.0072) and more severe chest pain (r_s = -0.29, 95% CI -0.5 to -0.007; p = 0.039). Conclusions: Bendopnoea can occur with pneumothorax, correlates with breathlessness and demonstrates a signal with worse chest pain.