Updated 2 May 2020
This page summarizes the minimum set of controllable parameters and recommended ranges, in order to ventilate a patient, summarized from Clinical.
Note: These are more aggressive than the Emergency Use Ventilator (EUV) Design Guidance from AAMI/CR501:2020. Please consult this document.
Caution: Patients must be under the management of a trained clinician.
- Respiratory Rate (RR) (breaths per minute): between 6 – 40. Note that the low RRs of 6 – 9 are only applicable to Assist Control.
- Tidal Volume (TV) (air volume pushed into lung): between 200 – 800 mL based on patient weight.
- I/E Ratio (inspiratory/expiration time ratio): recommended to start around 1:2; best if adjustable between range of 1:1 – 1:4*.
- Assist Control is based on a Trigger Sensitivity: When a patient tries to inspire, they can cause a dip on the order of 2 to 7 cm H2O, with respect to PEEP pressure (not necessarily equal to atmospheric pressure).
- Airway pressure must be monitored continually. Maximum pressure should be limited to 40 cm H2O at any time
- Plateau pressure should be limited to max 30 cm H2O.
- The use of a passive mechanical blow-off valve fixed at 40 cm H2O is strongly recommended. This is integrated into most manual resuscitators.
- Clinician require readings of plateau pressure and PEEP (refer to Clinical tab).
- PEEP of 5–15 cm H2O required; many patients need 10–15 cmH2O.
- Failure conditions must result in an alarm and permit conversion to manual clinician override, i.e. if automatic ventilation fails, the conversion to immediate ventilation must be immediate.
*Range determined based on several COVID-19 patients’ ventilator settings reported from Boston area ICUs.
This is a minimum requirement set for emergency use. Equipment designed for more regular use, even if for emerging markets, will require additional features to be used on a regular basis.
Ventilation on room air is better than no ventilation at all. Blending of oxygen and air gas mixture to adjust FiO2 is not important in an emergency scenario. It is certainly nice to have that ability and can easily be implemented with an oxygen/air gas blender that some hospitals already have.
COVID-19 can become aerosolized (airborne), so HEPA filtration on the patient’s exhalation is required or between the ventilator unit and the patient (at the end of the endotracheal tube) to protect clinical staff from certain infection. This can serve to provide heat and moisture exchange between exhaled and inspired air. In-line HEPA filters can usually be purchased alongside manual resuscitator bags.