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Is negative pressure ventilation any use in treating Covid-19? Iron lungs are easier to build than positive pressure ventilators. I imagine many HN readers coul
by mrob 7y ago
Is negative pressure ventilation any use in treating Covid-19? Iron lungs are easier to build than positive pressure ventilators. I imagine many HN readers could build something like a Both respirator[0] in their garage over a weekend. Using negative pressure ventilation might be a better option than trying to attach multiple patients to a positive pressure ventilator.
[0] https://en.wikipedia.org/wiki/Both_respirator https://en.wikipedia.org/wiki/Both_respirator
- fifteenforty 7y agoTheoretically yes, in fact it may actually be better. We have largely abandoned negative pressure ventilatory support for a number of practical reasons. Not least is that once you have intubated a patient, they are less contagious!
- JshWright 7y agoNo, in the case of ARDS, you need positive pressure (especially "back pressure" during exhalation) in order to keep the alveoli open. https://en.m.wikipedia.org/wiki/Positive_end-expiratory_pressure https://en.m.wikipedia.org/wiki/Positive_end-expiratory_pres...
- fifteenforty 7y agoWe are talking about negative pressure mechanical ventilation. Positive end expiratory pressure is just one way of splinting open alveoli. Maintaining recruitment and V/Q matching in ARDS can be achieved in multiple ways, including negative pressure mechanical ventilation.
- JshWright 7y agoInteresting, I'd be curious to know more. My understanding of NPV is that it's primarily useful in cases when the lungs are generally "functional" and some other issue is preventing adequate ventilation.
- AstralStorm 7y agoAnyway, the ventilator hardware is relatively easy to make, a gas pump, reduction and humidifier, plus a few hoses. Literally your granddad's CPAP sleep apnea machine is (almost?) good enough, if it has tuned oxygen intake. I would wager intubating actually makes most problems worse in case of damaged lungs, but with low odds only. The real problem will be getting actual oxygen (concentrators are not free) and people to tune the system.
- koheripbal 7y agoIs that what these are? https://www.youtube.com/watch?v=SVodALR3Zoo https://www.youtube.com/watch?v=SVodALR3Zoo
- rtkwe 7y agoNo negative pressure ventilators are iron lung type devices. [0] What's in that video look like just oxygen hoods which surround the head in very high oxygen air. [0] https://en.wikipedia.org/wiki/Iron_lung https://en.wikipedia.org/wiki/Iron_lung
- rtkwe 7y agoIt could be but we're even further behind being able to support people on negative pressure than we are on ventilators. The biggest issue is the neck gasket, they have to seal well enough to provide the negative pressure without being super tight while conforming to the geometry of people's necks. It's already a big problem for the small number of people left on iron lungs. https://www.wired.co.uk/article/iron-lung-maker-community https://www.wired.co.uk/article/iron-lung-maker-community
- jefftk 7y agoI wouldn't expect this to work: the problem with covid isn't that the patient's muscles are unable to handle the breathing but that the usable lung capacity is too low, right? But these are definitely worth looking into at least a little, since they're so much easier to make than a modern ICU ventilator.