The following details by Norma MT Braun, MD, FACP, FCCP Clinical Professor of Medicine provide a capsule of the evolution of respiratory care over the 20th century:-
Negative Pressure ventilation – the Iron Lung – instituted for Post-Polio patients, first used in 1928, was responsible for reducing death rates from 100% when the respiratory muscles were paralyzed to 50% with deaths due to pneumonia in the pre-antibiotic era & not having Oxygen available before 1960. It was very effective & long term polio patients lived their whole lives in Iron Lungs for sleep for greater than 60 years. Portable Chest Cuirasses, developed for patients who did not recover sufficient respiratory function to allow no respiratory support, could be removed from the more confining Iron Lung. Cuirasses supported quadriplegics 24 hours/day & allowed them to get educated & work full time. The development of positive pressure ventilators applied to intubated patients & their ease of institution along with smaller size displaced the Iron Lung. The new rules from government making alarms a requisite part of ventilators along with loss of experience using negative pressure ventilation led to their demise. We have learned that positive pressure ventilation has many untoward effects: ventilator associated pneumonia, airway trauma, pneumothorax, reduced cardiac output, loss of speech & swallowing, need for paralysis & sedation causing muscle loss & neuropathy among others. Now a modern version of the Cuirass, the ExoVent, has been developed for respiratory failure patients. Clinical trials in normal volunteers show that it is effective & nurses find them easy to use.. Approval & use will allow clinical trials to proceed comparing the ExoVent with conventional positive pressure ventilation for a diverse group of patients including those suffering from COVID-19.
Norma MT Braun, MD, FACP, FCCP
Clinical Professor of Medicine
Icahn School of Medicine
Mt. Sinai Health Systems
Mt. Sinai Morningside – Mt. Sinai West
Ombudswoman
Chair, Archives Committee
Department of Medicine
Senior Attending
Pulmonary/ Critial Care/ Sleep Division
1111 Amsterdam Avenue
New York, N.Y. 10025-1737
