| SnapShot perturbations (lung: single compartment) |
Single frequency (150 breath/min) forced oscillation waveform (sinusoidal) |
resistance (R) |
cmH2O.s/ml |
indicative of whole thorax |
dynamic lung resistance |
| compliance (C) |
ml/cmH2O |
ease with which lungs can be extended |
| elastance (E) |
cmH2O/ml |
elastic rigidity of the lungs |
| Primewaves (lung: multiple compartments) |
Broadband (multi-frequency) forced oscillation waveforms, typically denoted by duration (e.g., ‘Prime-8’) that also reflects frequency content |
tissue elasticity (H) |
cmH2O/ml/s |
indicative of lung tissue |
reflects energy conservation in the lungs |
| tissue damping (resistance) (G) |
cmH2O/ml/s |
reflects energy dissipation in the lungs |
| tissue hysteresivity |
Î=G/H |
|
| Newtonian resistance (Rn) |
cmH2O.s/ |
indicative of large airways |
resistance of the central airways |
| |
ml |
|
| Pressure-volume loops |
Slow (stepwise or continuous) inflation to total lung capacity (TLC) and deflation back to functional residual capacity |
elasticity index in Salazar-Knowles equation (K) |
/cmH2O |
|
|
| Maximum volume in Salazar-Knowles equation (A) |
ml |
|
indicative of total lung capacity |
| quasi-static compliance (Cst) |
ml/cmH2O |
|
elastic recoil at given volume |
| quasi-static elastance (Est) |
cmH2O/ml |
|
elastic recoil at given volume |
| hysteresis (area in PV loops) |
cmH2O/ml |
|
measure of atelectasis |
| Positive end-expiratory pressure |
Positive end-expiratory pressure of 2–3 cm H2O is adequate to maintain a normal end-expiratory lung volume in small animals |
end-expiratory lung volume (Vtr end) |
ml |
|
|
| Negative pressure forced expiration |
Lungs are inflated to TLC and then rapidly switched to a negative pressure reservoir, resulting in an expiratory flow |
forced expiratory volume in 0.1 s (FEV0.1) |
ml |
|
|
| forced expiratory volume in 0.2 s (FEV0.2) |
ml |
|
|
| forced vital capacity (FVC) |
ml |
|
|
| FEV0.1/FVC |
% |
|
|
| FEV0.2/FVC |
% |
|
|
