Prevalence and outcomes of diaphragmatic dysfunction assessed by ultrasound technology during acute exacerbation of COPD: A pilot study

ABSTRACT Background and objective The prevalence and clinical consequences of diaphragmatic dysfunction ( DD ) during acute exacerbations of COPD ( AECOPD ) remain unknown. The aim of this study was (i) to evaluate the prevalence of DD as assessed by ultrasonography ( US ) and (ii) to report the impact of DD on non‐invasive mechanical ventilation ( NIV ) failure, length of hospital stay and mortality in severe AECOPD admitted to respiratory intensive care unit ( RICU ). Methods Forty‐one consecutive AECOPD patients with respiratory acidosis admitted over a 12‐month period to the RICU of the University Hospital of Modena were studied. Diaphragmatic ultrasound ( DU ) was performed on admission before starting NIV . A change in diaphragmatic thickness ( ΔTdi ) less than 20% during spontaneous breathing was considered to confirm the presence of dysfunction ( DD +). NIV failure and other clinical outcomes (duration of mechanical ventilation MV , tracheostomy, length of hospital stay and mortality) were recorded. Results A total of 10 out of 41 patients (24.3%) presented DD +, which was significantly associated with steroid use ( P = 0.002, R‐squared = 0.19). DD + correlated with NIV failure ( P < 0.001, R‐squared = 0.27), longer intensive care unit (ICU) stay ( P = 0.02, R‐squared = 0.13), prolonged MV ( P = 0.023, R‐squared = 0.15) and need for tracheostomy ( P = 0.006, R‐squared = 0.20). Moreover, the Kaplan–Meyer survival estimates showed that NIV failure (log‐rank test P value = 0.001, HR = 8.09 (95% CI : 2.7–24.2)) and mortality in RICU (log‐rank test P value = 0.039, HR = 4.08 (95% CI : 1.0–16.4)) were significantly associated with DD +. Conclusion In hospitalized AECOPD patients submitted to NIV , severe DD was seen in almost one‐quarter of patients. DD may cause NIV failure, and impacts on the use of clinical resources and on the patient's short‐term mortality.