## 3 Results  
The presented _P_aw and _Flow_ waveforms (Figure 7) indicate no change in the performance of the CoroVent ventilator after 24 h of continuous ventilation under unfavorable conditions. The mean measured _VTi_ at the beginning of the 24 h test period was 380.8 \(\pm\) 5.6 mL, and at the end of the test period, it was 382.0 \(\pm\) 4.1 mL, demonstrating consistent ventilator performance over time. In a separate battery runtime test, the ventilator operated for 126 \(\pm\) 8 min.  
The measured _VTi_ by independent reference demonstrates a strong correlation with the set _VT_, exhibiting near-perfect trendline dependence (Figure 8). Furthermore, all measured _VTi_ values fall within the required accuracy defined by the ISO standard [22].  
Figure 9 indicates an excellent stability of _PEEP_ across different _VT_ settings over the 20 min period. The measured _PEEP_ values were as follows: 4.96 \(\pm\) 0.25 cmH\({}_{2}\)O for _VT_ = 225 mL, 4.90 \(\pm\) 0.24 cmH\({}_{2}\)O for _VT_ = 375 mL, 5.01 \(\pm\) 0.21 cmH\({}_{2}\)O for _VT_ = 525 mL, and 5.04 \(\pm\) 0.21 cmH\({}_{2}\)O for _VT_ = 675 mL (mean \(\pm\) SD).  
Figure 8: Reference _VTi_ versus set _VT_ for four _VT_ settings ranging from 225 to 675 mL and variable _TiO_\({}_{2}\) at _PEEP_ = 5 cmH\({}_{2}\)O, _RR_ = 20 min\({}^{-1}\), and _IE_ = 1.2. The blue dotted line represents the determined trendline and the black solid line represents the perfect trendline. The black dotted lines represent the maximum acceptable deviation from the set tidal volume value required by international standard ISO 80601-2-12:2020 for critical care ventilators [22].  
Figure 7: (**A**) _P_aw waveforms and (**B**) _Flow_ waveforms recorded at the beginning of the 24 h test period (blue) and at the end of the 24 h test period (red) under unfavorable conditions. The waveforms are intentionally shifted in time by approximately 50 ms to allow the waveforms to be compared with each other.  
A comparison of measured _VTi_ values between the CoroQuant of the CoroVent ventilator and the independent reference V900A gas flow analyzer is presented in Figure 10. The results indicate that CoroVent consistently measured _VTi_ 7.6-9.0 mL lower than the reference, depending on the set _VT_. Additionally, as the _VT_ increases, the variability in _VTi_ differences also increased. Lower average _VTi_ values were observed at a preset _FiO_2 of 21% across all _VT_ settings.  
Figure 11 illustrates the effect of increasing _PEEP_ on Paw, _MV_, and _VTi_ when the _P_lim was set to 30 cmH2O. As shown in Figure 11A, inspiratory pressure started to be limited as _PEEP_ was gradually increased during respiratory cycles. The corresponding reductions in _MV_ and _VTi_, dependent on the _PEEP_ setting, are presented in Figure 11B.C. Under the given ventilation setting and test lung configuration, pressure limitation became evident at _PEEP_\(\geq\) 10 cmH2O. When _PEEP_ was increased to 20 cmH2O, _MV_ decreased from 7.5 L/min to 4 L/min.  
Figure 10: Bland–Altman plot of differences in _VTi_ measurements between CoroVent and the reference Fluke Biomedical VT900A gas flow analyzer (Fluke Biomedical LLC, Everett, WA, USA). The differences are plotted against the mean of the _VTi_ values obtained for each set _VT_.  
Figure 9: _PEEP_ recorded over a 20 min period for _VT_ settings ranging from 225 to 675 mL and variable _FiO_2.