Re:Pandemic Ventilator Project
by haldujai on Saturday March 14, 2020 @04:48AM
(#22574022)
To keep it simple you have a device that increases pressure through a closed circuit to push air into the lungs, when its time to exhale it drops pressure (although is still positive pressure i.e PEEP) that is weaker than the natural recoil/elasticity of the chest wall combined with gravity in a supine patient and allows exhalation.
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Re:Pandemic Ventilator Project
by bearsnowstorm on Saturday March 14, 2020 @06:13AM
(#22574312)
Agree. I'd add that my comment above about exhalation being passive is true in adult ICU practice. In high frequency oscillatory ventilation (HFOV) exhalation is active (a piston actively creates a negative pressure in the breathing circuit). I understand this is still used quite a bit in neonates (though I don't do NICU, so not an expert) but has gone out of favour in adults in a big way due to the results of trials like OSCILLATE (https://www.nejm.org/doi/full/10.1056/NEJMoa1215554). Probably still used in some centres as a rescue therapy, but I haven't used it in years (we'd use VV ECMO for that purpose).