Fig. 4. Differential tidal volume and PEEP during ventilation of two pigs on the iSAVE with closed-circuit ventilation.

(A) Summary of ventilatory and respiratory parameters. Mean ± SD was calculated from 300 breathing cycles. No significant differences were found between ventilation with and without differential PEEP (homoscedastic two-tailed t test, P > 0.05). (B) Pressure, flow, and volume waveforms for the two animals. Pig A (blue) and pig B (black) were ventilated with PEEP of 5 and 10 cmH₂O, respectively.