Table 1 Modelling details for breathing sequences
From: Contemporary portable oxygen concentrators and diverse breathing behaviours -- a bench comparison
Scenario and modelling guidance | Breath rate /min | Effort | Nasal Tidal Volume | Rin / Rex cmH2O/ L/sec | Crs mL/ cmH2O |
|---|---|---|---|---|---|
COPD patient, onset of exertion: Progressive increase in breath rate, inspiratory effort amplitude, and expiratory effort contribution, guided by references [13, 14]. | 20–34 | Figure 2(b) | 234 mL–700 mL (100% nasal) | 8 / 13 | 75 |
Low demand COPD patient at rest: Lower-than-typical volume for adult COPD. From Fig. 1 of reference [15], the lowest minute ventilation for an awake COPD patient in this cohort was 5.1L/min. A chronic stable COPD resting breath rate of 17/min was adopted [16]. | 17 | Figure 2(a) dashed curve | 304 mL (100% nasal) | 6 / 11 | 75 |
COPD patient, reduced nasal fraction: Sleeping COPD patient with average minute ventilation, breathing through both nose and mouth. Oronasal breath partitioning guided by Fig. 4 of [17]: for their subjects over 45 years old, oral proportion was 51% (median) or 45% (mean). An oral proportion within this span was used: 47%. Median ventilation for a COPD patient during REM sleep: 5.9 L/min from Fig. 1 of reference [15]. Mean breath rate during REM for nocturnal desaturators, Fig. 3 of [15]: 17.6/min. Compliance reduced and resistance increased consistent with supine posture and sleep [18]. | 17.6 | Figure 2(a) solid curve | 182 mL (53% nasal, total VT of 343 mL) | 12/ 15 | 65 |