What Is A Ventilator And How Does It Work?
A medical ventilator, or more colloquially “ventilator,” is a machine used in a medical setting to provide breathing support to patients who have difficulty in breathing. The machine is designed to move breathable air in and out of the patient’s lungs to make up for the loss of oxygen caused due to insufficient breathing. It is primarily used in intensive care and emergency medicine.
The modern positive pressure ventilator is made up of either a compressible air reservoir or a turbine, air and oxygen supplies, valves and tubes, and finally a disposable unit called a “patient circuit”.
The patient circuit contains a set of three lightweight plastic tubes – one for inhaled air, one for patient pressure and one for exhaled air. Depending on the seriousness of the patient’s condition, these patient circuits can be invasive or non-invasive. The invasive methods require tubes to be inserted into the patient’s body, whereas the non-invasive methods mainly require nasal masks to assist the patient.
The turbine or turbopump part of the ventilator pushes air through the machine, with a flow valve that adjusts the pressure, which is calculated based on the patient’s body parameters. When the pressure is released, the patient will exhale passively because of the elasticity of their lungs. This exhaled air is released through a one-way valve in the patient circuit called the patient manifold.
Ventilators are also primed for any and all kinds of exigencies and have a lot of checks and balances in place. Patient-specific parameters such as pressure of air, volume of air, flow speed and general parameters such as air leakage, mechanical failure, power failure, battery backups, oxygen tanks, and a remote control are all equipped with sensors and monitors. This is meant to make sure that the patient doesn’t lose those precious few breaths which could even cost a life.
The modern ventilator traces its history to technology which started almost in the late 1600s, when an English scientist, John Mayow came up with the idea of external negative pressure ventilation. He built a model that used bellows and a bladder to mimic the function of the lungs. In 1832, Scottish doctor John Dalziel built what was labeled as an “iron lung.” This was essentially a chamber in which the patient was placed and an artificial atmospheric pressure was created to help the breathing process become easier. This was used widely during the polio epidemic in the west in the 1930s.
It is due to the relentless hard work of both doctors and engineers, from the early days of the 20th century, that has led to leaps in the technology of ventilators and resulted in advanced and computer-controlled life savers that we have come to depend upon today.