Table 3 Diaphragmatic ultrasound
Parameter | Setting | Target | Cut-off values | Number of patients (n) |
|---|---|---|---|---|
Excursion | Healthy subjects | Normal values | Quiet breathing: 0.9–1 cm Voluntary sniffing: 1.6–1.8 cm Deep breathing: 3.7–4.7 cm | (210) |
Dysfunction |  < 2 cm |  | ||
ICU-IMV | Successful extubation |  > 1.1 cm | (52) | |
ICU-IMV | Dysfunction |  < 11 mm | (34) | |
Thickness | Healthy subjects | Normal values | 1.8–3.0 mm A side-to-side difference in thickness at end expiration of > 0.33 cm is abnormal Minimally affected by age, gender, body habitus, or smoking history | (150) (109) |
Successful extubation |  > 1.7 | (63) | ||
Covid-19 spontaneously breathing | Need of IMV | 2.2Â mm | (77) | |
ICU-IMV | Diaphragmatic weakness | 2.4 ± 0.8 mm | (107) | |
ICU-IMV | Atrophy | 1.9 ± 0.4 mm | (54) | |
ICU | Atrophy | Reduction > 10% within the first 5 days | (97) | |
Thickening fraction | Healthy subjects | Normal values with tidal breathing | 20% ± 16% right side 23.5% ± 24.4 left side | (150) |
ICU COVID-19 CPAP | CPAP failure | 21% | (27) | |
ICU-IMV | Successful SBT | 36% | (46) | |
ICU-IMV | Successful weaning | 26% | (34) | |
ICU-IMV | Diaphragm dysfunction; Length of IMV | 29% | (112) | |
ICU-IMV | Successful extubation | 34% | (52) | |
ICU-IMV | Successful extubation | 20% | (56) | |
ICU-IMV | Successful extubation | 30% | (63) | |
Diaphragmatic Kinetics by TDI | ICU-IMV | Extubation failure | Inspiratory peak velocity: ≥ 3.1 cm/s Inspiratory mean velocity: ≥ 1.6 cm/s Inspiratory acceleration time: ≥ 8.8 cm/s2 Peak relaxation velocity:  > 2.6 cm/s Expiratory mean velocity: ≥ 1.1 cm/s Expiratory acceleration time: ≥ 11.2 cm/s2 | (100) |