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Medical Ventilators – A Mechanical Way to Breathe in And Out

Medical Ventilators – A Mechanical Way to Breathe in And Out

The 21st century is the age of innovations and development. With relief and comfort, more and more inventions have led to harmful effects on human lives as well. Like every other field, advancements have also been made in the medical industry. These advancements have revolutionized medicine immensely. 

Ventilators are one of the most important inventions of the 20th century. It helps patients with respiratory problems and let them breathe comfortably. These days, any dimension of a medical ventilator can be found at hospitals, health care centers, and even at the patients’ homes to provide intensive care, either through a standalone unit or as part of an anesthesia machine.

Ventilators are being used in ICUs (intensive care units)  in hospitals all around the world making them expensive. Those with resources can buy new ventilators but the less fortunate are confined to a refurbished ventilator.


The first invasive ventilator was introduced in 1928 as “Drinker respirator”  which was later improved by John Heaven Emerson. It was called Iron Lung at that time. The use and advancement of the ventilator (at that time known as “respirator”) was very important in the Polio Epidemic of the mid 20th century.

John Heaven Emersion in 1949 worked with the anesthesia department at Harvard University and developed an anesthesia assister. 

In 1971, SERVO 900 was introduced. It was a small, silent effective electronic ventilator that left behind all of its predecessors that were combustible and loud.

Later in 1999 SERVO 300 was introduced with the improvement that it can be used for every age group from neonates to adults. The improvements are still ongoing reducing the size of the medical ventilators.

Purpose And Working Of Ventilator:

The basic use of a ventilator is to assist in the breathing process of people suffering from acute respiratory issues and in need of a surgical procedure. It is being used to give anesthesia to the patient for surgery. 

The idea behind the use is to assist the respiratory organs in the breathing process. It is usually incubated through the mouth into the airway of the patient and then regulated according to the patient’s condition. It pushes breathable oxygen in the lungs for the aid of oxygen flow through the blood which then in return release carbon dioxide.

Usually, a patient with low oxygen levels or high carbon dioxide is recommended the use of a ventilator. Mechanical ventilation also rests the respiratory muscles and is an appropriate therapy for respiratory muscle fatigue.

Types Of Ventilators:  

Ventilators are basically divided into types depending on pressure-volume and mode of use.

Modes Of Ventilators.

There are typically two modes of user-initiated (A/C) and ventilator controlled(SPONT).

In the user-initiated mode, either the user or the ventilator initiates the breathing and assists in the breathing process by delivering continuous breaths every time depending on the pressure or volume. 

In the spontaneous mode, the patient initiates the breathing but it is then controlled by the ventilator and the patient can breathe at a continuous positive airway pressure.

Pressure-Based Ventilators.

There are two types of ventilators depending on their pressure i.e. positive-pressure ventilators and negative-pressure ventilators. 

Negative-pressure ventilators were used in the early period of ventilators; they work identically to the natural way of human breathing. Negative-pressure ventilators create low pressure in the lungs aiding the flow of oxygen based on the principle that gases flow from high pressure to low pressure.

However, positive-pressure ventilators work contrary to the negative-pressure ventilators by creating high pressure at the airways. 

Volume-Based Ventilators.

In volume-targeted ventilation, tidal volume is the independent variable set by the physician or respiratory therapist, and airway pressure is the dependent variable. In this type of ventilation, airway pressure is a function of the set tidal volume and inspiratory flow rate, the patient’s respiratory mechanics (compliance and resistance), and the patient’s respiratory muscle activity.

In pressure-targeted ventilation, airway pressure is the independent variable, and tidal volume is the dependent variable. The tidal volume during pressure-targeted ventilation is a complex function of inspiratory time, the patient’s respiratory mechanics, and the patient’s own respiratory muscle activity.


In short, if we say that in the battle of life and death ventilators have helped the doctors and patients the most, it would not be wrong. They are used with very much care and sensitivity because a slight fluctuation can cause severe damage to the patient.

They are always packed with alternatives and extra batteries in case of power failure. These are very expensive devices and everyone cannot afford this acute life care equipment. But fortunately, there are companies offering refurbished ventilators.

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