Diaphragm ultrasound: a bedside test for functional pulmonary assessment

Abstract

Background
Evaluation of diaphragm when combined with spirometry, can be useful to respiratory function assessment. Forced expiratory diaphragm excursion in the first second (FEDE1)/EDEmax % is a novel diaphragm kinetics index that is related to lung function assessed by diaphragm ultrasound.


Aim
To rate the credibility of FEDE1/EDEmax % as a screening test in the assessment of chronic obstructive pulmonary disease (COPD) and interestitial lung fibrosis (ILD) patients compared with healthy control.


Patients and methods
This case-control study included three groups: COPD, ILD, and control groups. All included patients were exposed to full spirometry and diaphragm ultrasound (to be done after and within 24 h from spirometry maneuver). Measures of spirometry included forced expiratory volume in one second (FEV1), forced vital capacity (FVC) and FEV1/FVC%. Measures of ultrasound included FEDE1, EDEmax and FEDE1/EDEmax% (recorded during forced expiration maneuver). Results: FEV1, FVC and FEV1/FVC%. had significant positive correlations with FEDE1, EDEmax and FEDE1/EDEmax%, respectively. FEV1, FVC, and FEV1/FVC were crucially lower in COPD and ILD compared with control group. However, FEV1/FVC was comparable to the control group in ILD. Cut off values of FEDE1/EDEmax% less than or equal to 74.1 in COPD and greater than or equal to 78.7 combined with EDEmax less than or equal to 2.6 cm in ILD were detected on the receiver operating curve to discriminate them from the control group.


Conclusion
Diaphragm excursion evaluated by ultrasound during forced expiration is correlated with spirometeric values in both COPD and ILD patients. It can be used as an add-on screening tool for the diagnosis of both COPD and ILD patients.