# Ultrasonographic diaphragmatic assessment as an emergency mortality predictor in acute exacerbation of COPD

## TL;DR

This study explores how ultrasound of the diaphragm can predict mortality in patients with acute COPD flare-ups, comparing it to existing scoring systems.

## Contribution

The study introduces diaphragmatic ultrasound as a novel, non-invasive mortality predictor in acute COPD exacerbations.

## Key findings

- Diaphragmatic ultrasound metrics showed comparable or better mortality prediction than BAP65 and DECAF scores.
- Strong correlations were found between diaphragmatic measurements and established scoring systems.
- Mortality was associated with multiple comorbidities in the study population.

## Abstract

To evaluate the role of diaphragmatic ultrasound as a mortality predictor in acute exacerbation of chronic obstructive pulmonary disease (AECOPD), compared to the DECAF and BAP65 scoring systems.

The diaphragm is the primary muscle of respiration and is often compromised during AECOPD. Bedside ultrasound offers a non-invasive method to assess diaphragmatic function. Early identification of patients at high risk of mortality upon presentation may aid in appropriate triage and management.

This observational pilot study included 50 patients presenting to the emergency department with AECOPD. For each patient, the BAP65 score (Blood urea nitrogen, altered mental status, Pulse, Age ≥ 65), DECAF score (Dyspnea, Eosinopenia, Consolidation, Acidemia, Atrial fibrillation), diaphragmatic thickness fraction (diTF), and diaphragmatic excursion (diEX) were recorded at presentation.

Of the 63 patients initially enrolled, 50 completed the study, with a predominance of male participants. Mortality occurred in 16% of cases. Deceased patients were significantly more likely to have comorbidities such as diabetes mellitus, hypertension, atrial fibrillation, ischemic heart disease, cardiomyopathy, cerebrovascular stroke, chronic kidney disease, and reliance on home oxygen therapy (P < 0.05). Receiver operating characteristic (ROC) analysis identified cutoff values for each predictor: BAP65 ≥ 5, DECAF ≥ 3, diTF ≤ 21%, and diEX ≤ 2.5 cm. Corresponding area under the curve (AUC) values were: BAP65, 0.833, CI = 0.621 to 1.000; DECAF, 0.976, CI = 0.933 to 1.000; diTF, 0.848, CI = 0.670 to 1.026; and diEX, 0.884, CI = 0.787 to 0.981. Spearman’s rank correlation revealed a strong negative correlation between diEX and DECAF (r = -0.771, CI= -0.862–-0.628, p < 0.001), and between diEX and BAP65 (r = -0.626, CI = -0.757–-0.448, p < 0.001). Moderate negative correlation was also observed between diTF and DECAF (r = -0.451, CI = 0.616–-0.241, p < 0.001), and weak negative correlation between diTF and BAP65 (r = -0.341, CI =-0.570–-0.069, p = 0.01). However, these finding should be interpreted with caution due to small sample size.

Diaphragmatic ultrasound is a rapid and reliable tool for predicting mortality in patients with AECOPD presenting to the emergency department. It demonstrates comparable or superior predictive value to established scoring systems such as BAP65 and DECAF. However, this finding should be interpreted with caution and further studies with larger sample sizes are warranted to validate these findings.