Diaphragm Ultrasound and Surface Electromyography as Predictors of Clinical Deterioration in Acute Exacerbations of COPD: A Prospective Observational Study

Introduction Acute exacerbations of chronic obstructive pulmonary disease without respiratory acidosis lack reliable and practical physiological markers to monitor treatment response or predict clinical deterioration. Methods In this prospective observational study, 51 hospitalised AECOPD patients without respiratory acidosis underwent diaphragm ultrasound and surface electromyography within 48 h of admission and at discharge. Associations between study parameters and dyspnea (Borg scores and mMRC scales) were assessed, and their predictive value for clinical outcomes (progression to non-invasive ventilation or in-hospital death, and 30-day readmission). Results An increase in DE during maximal inspiration associated weakly, yet significantly, with improvements in Borg scores (r s −0.365, p 0.011). A higher diaphragmatic excursion tidal breathing/maximal inspiration ratio at admission was associated with in-hospital deterioration (OR per 0.1-unit increase 1.59; 95% CI: 1.05 to 2.41; p 0.029) and exploratory analysis suggested discriminative value of the Excursion-to-sEMG ratio (0.941; 95% CI 0.855 to 1.000; p 0.013), although interpretation is limited by few events.. Higher Borg scores (OR 2.19; 95% CI 1.22 to 3.94; p 0.009) and lower thickening fraction (AUROC 0.807; 95% CI 0.687 to 0.927; p 0.004) at discharge were independently associated with 30-day readmission. Conclusion Bedside ultrasound and sEMG provide potential physiological markers associated with clinical deterioration in non-acidotic AECOPD patients. These exploratory findings suggest a role in identifying at-risk patients and guiding personalised care. Validation in larger cohorts with more events is needed. Furthermore, we found that short-term readmission risk may be predicted by a simple bedside question: “How breathless do you feel right now?”