Ventilatory variables during intermittent positive pressure ventilation (IPPV) and negative pressure ventilation (NPV)
| Variable | IPPV | NPV |
|---|---|---|
| Minute volume (ml/kg) | 150 to 220 | 140 to 220 |
| Frequency (breaths/min) | 15 to 22 | 30 to 50 |
| Tidal volume (ml/kg) | 10 to 15 | 5 to 7 |
| Pinsp (cm H2O) | ||
| Group 1 | +16 to +20 | −18 to −24 |
| Group 2 | +18 to +23 | |
| Pexp (cm H2O) | 0 to 2 | +1 to + 4 |
| Paw (cm H2O) | + 5 to + 9 | − 6 to −9 |
| Pressure support (cm H2O) | + 3 to + 5 | |
| Fio 2 Group 1 | 0.25 to 0.35 | as IPPV |
| Group 2 | 0.3 to 0.6 | as IPPV |
Pinsp, inspiratory pressure; Pexp, expiratory pressure; Paw, mean airway pressure; Fio 2, inspired oxygen fraction.