Table 2.
Determination of meeting E-Vent Key Ventilation Technical Specifications [74].
| Key Ventilation Specifications | E-Vent Recommendations | RepRapable OS Design |
|---|---|---|
| 2.1. Control of Breathing Rate (breaths per minute) | 8–30 BPM | 5–45 BPM, controlled by user interface |
| 2.2 Control of Tidal Volume (air volume pushed into lung in mL) | 200–800 mL based on patient weight | 100–846 mL, controlled by user interface |
| 2.3 Control of I/E Ratio (inspiratory/expiration time ratio) | best if adjustable between range of 1:1–1:4 | Adjustable between range of 1:1–1:4, controlled by user interface |
| 2.4 Assist detection pressure. When a patient tries to inspire, they can cause a dip on the order of 1–5 cm H2O, with respect to PEEP pressure (not necessarily = atmospheric). | Required | Can be added based on pressure [132] or temperature [66] feedback |
| 3. Airway pressure must be monitored | Required | Contains two pressure sensors connected between the ventilator and patient via an airway tube, pressures are shown on the LCD screen |
| 3.1.1 Pressure limits: Max pressure | 40 cm H2O | Alarms sound if pressure exceeds 40 cmH2O |
| 3.1.2 Pressure limits: Plateau pressure | 30 cm H2O | Can be added by introducing a pause at the end of the inspiratory phase [132] |
| 3.2 Passive mechanical blow-off valve | 40 cm H2O | Can be purchased together with the self-inflating bag kit |
| 3.3.1 Monitor plateau pressure | Clinician viewable | Can be added by modifying the control algorithm |
| 3.3.2 Monitor PEEP | Clinician viewable | Can be added, need software to see the quantitative value |
| 3.4 PEEP | 5–15 cm H2O | 2–11 cm H2O based on observed data during testing |
| 4. Manual clinician override | Failure of automatic ventilation allows conversion to immediate ventilation. | Yes |
| 5. Ability to use ventilation on room air. Implemented with an oxygen/air gas blender that some hospitals already have. |
Required for emergencies | Yes |
| 6. HEPA filtration on the patient’s exhalation | Required because COVID-19 can be aerosolized | Can be added, HEPA filters can usually be purchased alongside manual resuscitator bags. |
| 8. Failure conditions result in alarm | Required | Alarms sound if pressure exceeds the allowed limits from 5 to 40 cmH2O |