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Iron Lung vs. Ventilator

Posted

I am an engineer and not a health care professional, so I'd appreciate some feedback from people on the medical side. There is widespread concern about the shortage of ventilators, and also an observation that the ventilators themselves can cause damage (e.g. barotrauma, intubation-related infections). Are there reasons the much older, but proven (at least in the case of polio) iron lung technology cannot be used? It does not require intubation and is apparently less stressful on the lungs.

https://newatlas.com/medical/british-engineers-modern-iron-lung-covid-19-ventilator-alternative/

"Unlike ventilators, the exovent doesn't require intubation and is much simpler in design and operation. According to the consortium responsible for its design, patients can remain awake, take medications, eat and drink, and talk to their loved ones on the phone. In addition, the machine improves heart efficiency by 25 percent over conventional ventilators, which can adversely affect cardiac functions."

Also https://www.ncbi.nlm.nih.gov/pubmed/15065832

"This study suggests that iron lung ventilation is as effective as invasive mechanical ventilation in improving gas exchange in chronic obstructive pulmonary disease patients with acute respiratory failure, and is associated with a tendency towards a lower rate of major complications."

llg, PhD, RN

Specializes in Nursing Professional Development. Has 44 years experience.

I'll chime in with 1 reason:

1. We don't have them available. While they might work just fine on some patients, we don't have them available to use.

They may be in hospital basements somewhere where they've been since the 1950's. Probably a ton of the old Bird and MA1 vents too but nobody would know what to do with them.

CampyCamp, RN

Has 18 years experience.

There are quite a few negative pressure vents in use. Very few iron lungs (a joke about bringing them out of storage just because residents want to try out all the order sets in the computer went around several months ago on gomer blog) but there are many people with chronic muscular disease using cuirass shells and soft wrap vents. I think the key there is muscular disease. They mimic the ventilation effect of chest expansion and the diaphragm but I don't think they recruit alveoli to enhance gas exchange like positive pressure vents. Intubation also helps manage secretions, keep the airway open if mental status changes, get medications deep into the lungs, and provide the doctor with a route to perform bronchoscopy.

Bill, I had the same thoughts as you. I posted in the pulmonary nursing forum. I called friends who work in hospitals and they asked respiratory therapists about using a modern day iron lung. The response from them was that the iron lung style of negative pressure ventilator would not work with Covid19 patients. This was because of the infection and loss of elasticity in their lungs due to the disease. The polio patients lungs were otherwise healthy but they couldn't breathe due to loss of muscle contractions. They said the positive pressure ventilator is needed to keep the aveoli inflated. Negative pressure ventilators, could be used in noncovid cases to free up the positive pressure ventilators. This is the answer I got after many questions and it makes sense to me.

That makes sense to me too, then. There is obviously a difference between polio patients and COVID-19 patients. It sounds like negative pressure will not expand the aveoli, then.

heron, ASN, RN

Specializes in Hospice. Has 40 years experience.

23 hours ago, sevensonnets said:

They may be in hospital basements somewhere where they've been since the 1950's. Probably a ton of the old Bird and MA1 vents too but nobody would know what to do with them.

I would ... cut my teeth on ‘em!

CampyCamp, RN

Has 18 years experience.

1 hour ago, heron said:

I would ... cut my teeth on ‘em!

I remember the MA1s and the Bears. I always thought the dials were easier to adjust than the buttons and touchscreens.

Runsoncoffee99

Specializes in Peds. Has 17 years experience.

I had a similar question but with Cpap or Bipap machines instead.

NRSKarenRN, BSN, RN

Specializes in Vents, Telemetry, Home Care, Home infusion. Has 44 years experience.

COVID-19 patients in ICU today have more that respiratory failure--multiple body systems failing too. Patients are intubated with breathing tube into trachea airway, attached to ventilator +being placed PRONE on the bed- that is turned to be lying face down on the bed for up to 16hrs/day; not practical in an iron lung.

I never liked working with the iron lungs because it made my skin hurt. Literally.