Diaphragm ultrasound and surface electromyography as predictors of clinical deterioration in acute exacerbations of COPD: a prospective observational study.
Source: PubMed, NCBI / U.S. National Library of Medicine
Acute exacerbations of COPD without respiratory acidosis lack reliable and practical physiological markers to monitor treatment response or predict clinical deterioration. In this prospective observational study, 51 hospitalised acute exacerbations of COPD (AECOPD) patients without respiratory acidosis underwent diaphragm ultrasound and surface electromyography within 48 h of admission and at discharge. Associations between study parameters and dyspnoea (Borg scores and modified Medical Research Council scales) were assessed, and their predictive value for clinical outcomes (progression to noninvasive ventilation or in-hospital death, and 30-day readmission). An increase in diaphragm excursion during maximal inspiration associated weakly, yet significantly, with improvements in Borg scores (r=-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-surface electromyography (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 (area under the receiver operating characteristic curve 0.807, 95% CI 0.687 to 0.927; p=0.004) at discharge were independently associated with 30-day readmission. Bedside ultrasound
Abstract
Acute exacerbations of COPD without respiratory acidosis lack reliable and practical physiological markers to monitor treatment response or predict clinical deterioration. In this prospective observational study, 51 hospitalised acute exacerbations of COPD (AECOPD) patients without respiratory acidosis underwent diaphragm ultrasound and surface electromyography within 48 h of admission and at discharge. Associations between study parameters and dyspnoea (Borg scores and modified Medical Research Council scales) were assessed, and their predictive value for clinical outcomes (progression to noninvasive ventilation or in-hospital death, and 30-day readmission). An increase in diaphragm excursion during maximal inspiration associated weakly, yet significantly, with improvements in Borg scores (r=-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-surface electromyography (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 (area under the receiver operating characteristic curve 0.807, 95% CI 0.687 to 0.927; p=0.004) at discharge were independently associated with 30-day readmission. 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?"