Dynamic measurements of phonation valve with simulated patient breaths produced by a sinusoidal pump#
| Phonation valves | Pmin cmH2O | R cmH2O·L−1·s−1 | WOB J·min−1 | PTP cmH2O·s−1·min−1 | tD ms | VL mL |
| V0 | −0.09 | 0.1 | 1.60 | |||
| V1 | −3.59 | 5.9 | 2.2 | 51.7 | 170 | 3.5 |
| V2 | −2.32 | 3.8 | 1.5 | 36.1 | 0 | 0 |
| V3 | −1.47 | 2.3 | 0.9 | 24.0 | 60 | 0.48 |
| V4 | −1.32 | 2.1 | 0.9 | 21.5 | 45 | 0.3 |
| V5 | −2.24 | 3.4 | 1.5 | 34.0 | 60 | 0.42 |
| V6 | −0.95 | 1.3 | 0.5 | 14.6 | 25 | 0.2 |
Pmin: minimal pressure observed during inspiration; R: resistance; WOB: work of breathing; PTP: pressure time product; tD: delay between beginning of expiration and closure of the valve; VL: leak volume observed between the beginning of expiration and closure of the valve; V0: measurements realised without any phonation valve. #: using a tidal volume of 0.5 L, a peak flow rate of 0.5 L·s−1 and a respiratory rate of 20 breaths·min−1.