Ultrasound analysis of diaphragm kinetics and the diagnosis of airway obstruction: the role of the M-mode index of obstruction.
Diaphragm motion in forced expiration can be analyzed using M-mode ultrasound in an anterior subcostal approach. Maximum expiratory diaphragmatic excursion (EDEMax) and forced expiratory diaphragmatic excursion in the first second (FEDE1) are considered the physiopathological analogues of vital capacity (VC) and forced expiratory volume in the first second (FEV1). As the FEV1/VC % ratio is used as a marker of obstruction, our aim was to determine if the ratio FEDE1/EDEMax (M-mode index of obstruction [MIO]) differs between healthy subjects and patients with airway obstruction. One hundred twenty-four outpatients were examined by diaphragm ultrasound after spirometry. The MIO, expressed as the mean ± standard deviation (range), was 87.08 ± 6.64 (72.84-100) in the healthy group (N = 61) and 67.09 ± 12.49 (33.33-91.30) in the group with obstructed airways (N = 63). The difference between the two groups was significant (p < 0.0001), and MIO was significantly correlated with FEV1/VC (p < 0.0001). A MIO <77 was identified as a possibile cutoff for suspecting an obstructive spirometric pattern with a 95.5% positive predictive value. The MIO can be interpreted as a speed index of diaphragmatic relaxation that seems to be slower in obstructed patients and could be used to screen for obstructed airway diseases.
Muldisciplinary Medicine Unit, General Hospital "San Luca," Trecenta (Rovigo), Rovigo, Italy. Electronic address: alessandro.zanforlin@gmail.com.
Alessandro
A
Zanforlin
Pulmonary Medicine Department, University Hospital "A. Gemelli," Università Cattolica del Sacro Cuore, Rome, Italy.
Andrea
A
Smargiassi
Pulmonary Medicine Department, University Hospital "A. Gemelli," Università Cattolica del Sacro Cuore, Rome, Italy.
Riccardo
R
Inchingolo
Pulmonary Medicine Department, University Hospital "A. Gemelli," Università Cattolica del Sacro Cuore, Rome, Italy.
Alessandro
A
di Marco Berardino
Pulmonary Medicine Department, University Hospital "A. Gemelli," Università Cattolica del Sacro Cuore, Rome, Italy.
Salvatore
S
Valente
Muldisciplinary Medicine Unit, General Hospital "San Luca," Trecenta (Rovigo), Rovigo, Italy.
Emilio
E
Ramazzina
D000368:Aged; D000402:Airway Obstruction / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003964:Diaphragm / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging / Q000503:physiopathology; D013147:Spirometry; D014463:Ultrasonography; D014797:Vital Capacity
Airway obstruction; Chronic obstructive pulmonary disease; Diaphragm; Spirometry; Ultrasound