Figure 6.

Effect of different ventilator respiratory settings and respiratory rate on mean tidal volume delivered to the helmet (VTinsp Helmet) and to the Active Simulator Lung (VTinsp Lung) with HF-BiPAP, BiVent, and PSV ventilation. Measurements were made in normal (compliance 90 ml/cmH₂O, resistance 3 cmH₂O/l/s), restrictive (compliance 30 ml/cmH₂O, resistance 3 cmH₂O/l/s), and obstructive lung conditions (compliance 90 ml/cmH₂O, resistance 15 cmH₂O/l/s) at low (2.5 cmH₂O) and high inspiratory efforts (10 cmH₂O) at a respiratory rate of 15 and 30 breaths per minute. Grey columns = inspiratory VT to the Active Lung Simulator (VTinsp Lung); white columns = inspiratory VT to the Helmet (VTinsp helmet). BiVent = time-cycled pressure controlled switching between two continuous positive airway pressure levels; HF-BiPAP = high flow biphasic positive airway pressure; PSV = pressure support ventilation.