CELEBRATING 100: Respirators and Ventilators

March 19, 2020

As the coronavirus that causes COVID-19 spreads across the United States, availability of certain Personal Protection Devices and medical equipment to help protect health care workers and treat patients may be in high demand.
 
One key piece of equipment to provide necessary care to patients severely affected by COVID-19 is the ventilator, which can help the most seriously ill patients breathe. These machines are often crucial in sustaining life in certain emergency situations, so the potential respiratory effects of COVID-19 make the nation’s ventilator supply a core area of interest.
 
While today we consider a “respirator” to be an important piece of PPE (such as the N95 mask), decades ago hospitals were learning about “respirators” that were the precursor to today’s modern ventilator equipment. The following are excerpts taken from a 1948 Wisconsin Hospital Association newsletter, reporting on conferences held in Madison at the University of Wisconsin:

THE RESPIRATOR AND ITS CARE
Oscar E. Olson, Engineer, State of Wisconsin, General Hospital
The normal mechanism of respiration dependent upon changes in the pressure in relationship to atmospheric pressure. A respirator attempts to simulate the normal mechanism of respiration by producing pressure changes around the body of the individual. The body type of respirator with the patient's head and neck protruding has proved satisfactory. It functions by alternately producing negative and positive pressure or negative pressure alone.
 
CARE OF THE PATIENT IN THE RESPIRATOR
Marion J. Dunn, R. N., B. S., Instructor in Nursing
 
Poliomyelitis is not the only disease in which a respirator may be used. Other reasons for respiratory aid may be asthma, brain injury, severe respiratory infections and others. A patient is placed in a respirator for the first time only on a specific order from the doctor; later it may be a R.R.N. procedure as determined by the nurse.
 
The function of the respirator may be as an aid to voluntary respiration or as a complete substitute for voluntary respiration. The doctor and nurse use every effort to adjust the machine to the patient's rate of breathing rather than vice versa; however when a patient is completely dependent on the machine, the doctor will decide the respiratory rate necessary. Again the doctor is the one to determine the amount of positive and negative pressure needed by the patient and usually to make the initial adjustment, but the nurse must understand the regulation of pressures in order to maintain the machine on those pressures in the doctor's absence. Usual positive pressure is 0 to 5 cm. of water, negative pressure (vacuum) is from 15 to 20 cm. of water for adults, 10 to 15 cm. of water for children.

See full article here.
 
The 1918 influenza pandemic was the most severe pandemic in recent history, with many deaths due to the lack of medical equipment used decades later. That pandemic was caused by an H1N1 virus with genes of avian origin. Although there is not universal consensus regarding where the virus originated, it spread worldwide during 1918-1919. In the United States, it was first identified in military personnel in spring 1918. It is estimated that about 500 million people – or one-third of the world’s population at the time – became infected with this virus. The number of deaths was estimated to be at least 50 million worldwide with about 675,000 of those deaths occurring in the United States.

This story originally appeared in the March 19, 2020 edition of WHA Newsletter