Prior to the widespread use of intubation ventilation Iron Lungs, or negative pressure ventilation, were the method of choice for ventilation in medical settings.
In a prior pandemic, under emergency situations, it was found that positive pressure intubation ventilators normally used in anesthesiology resulted in higher patient survival rates.
But positive pressure intubation ventilation brought about other complications, including that of ventilator associated pneumonia (VAP). Known risk factors for development of VAP include "Non-modifiable risk factors include male gender, increased age (over 60 yr), history of chronic obstructive pulmonary disease" (Keyt et al.)
Interesting we find that the same list of risk factors are some of the more commonly known risk factors for COVID-19 morbidity.
It is known that noninvasive ventilation, such as the provided by a CPAP significantly reduce the development of VAP.
CPAP and BiPAP are known to reduce sleep apnea. Sleep apnea is a negative side effect that is common to the use of an Iron Lung (Mehta et al.)
The Iron Lung has been used to increase the blood arterial gas values for those hospitalized with Chronic Respiratory Failure.
By combining the use of use of BiPAP technology with Iron Lung usage it is hypothesised that blood arterial gas values can be raised in indicated patients. Such combination should reduce some of the known negatives including sleep apnea of Iron Lung usage, and reduce patient morbidity. In addition BiPAP can be used with supplemental O2, resulting in further oxygen delivery where indicated.
The use of BiPAP and Iron Lung will result in lower incidences of ventilator induced pneumonia. The double whammy of ventilator induced pneumonia may be a partial factor in the morbidity rate of COVID-19 infections.
Iron Lung has been shown to have advantages in treating both Chronic Obstructive Pulmonary Disorder and Acute Respiratory Distress Syndrome.
BiPAP usage as noninvasive positive pressure should be examined as potential treatment for patients in need of ventilator support, prior to intubation ventilation. If BiPAP alone is not effective the use of Iron Lung can further increase breath volume and gas exchange in the lungs.
BiPAP machines are available as off the shelf technology, in larger available numbers than intubation ventilators. Iron Lungs can be manufactured using different production lines than other medical equipment. For example common wood shop tools can cut and form plexiglass into the Iron Lung tank, that can be sterilized prior to induction to a hospital setting.
By using existing equipment and readily manufacturable new it should be possible to increase the availability of ventilation in situations where emergency need exceeds supply. It is possible that such treatment option will offer a survival advantage to the current intubation ventilation as a standard of care in COVID-19 cases.