What Is a Medical Ventilator & How Does It Work?

A medical ventilator is a medical device that is designed for the forced supply of a gas mixture (oxygen and compressed dried air) into the lungs in order to saturate the blood with oxygen and remove carbon dioxide from the lungs.

The ventilator can be used both for invasive (through an endotracheal tube inserted into the patient’s airways or through a tracheostomy) and for non-invasive artificial ventilation of the lungs – through a mask.

The ventilator can be either manual or mechanical. Compressed air and oxygen for the pneumatic supply of a mechanical device can be supplied from the central gas supply system of a medical institution or a compressed air cylinder (during transportation), or from an individual mini-compressor and an oxygen concentrator. In this case, the gas mixture must be warmed and humidified before being fed to the patient.

Modern ventilators are extremely high-tech medical equipment. They provide respiratory support to the patient in both volume and pressure.

At the moment, the most advanced technology for synchronizing the ventilator with the patient is the technology of neuro-controlled ventilation of the lungs, when the signal coming from the respiratory center of the medulla oblongata along the phrenic nerve to the diaphragm is recorded by special highly sensitive sensors located in the area of the transition of the esophagus to the stomach.

The high-frequency jet ventilator can provide both the actual high-frequency jet ventilation and the combined one. At the same time, pres-sure control is used to prevent lung barotrauma. A modern HF jet ventilator must have a built-in roller humidifier and a built-in heating system for the gas mixture to prevent severe complications from the respiratory tract. The possibility of dosing oxygen and control of carbon dioxide in the exhaled air is mandatory. It was invented by Philip Drinker and Luis Aghaziz Showem Jr. in 1927.

Popular medical ventilator models are Eagle 2 MR (Eagle II MR), Siemens Maquet Servo-i, Pu-ritan Bennett 840, Avante MVP Portable, Puritan Bennett 980, Viasys AVEA, Respironics V200, Drager Evita 4, Dräger Evita XL.

Who needs l mechanical ventilation?

Mechanical ventilation is necessary when the lungs can no longer inhale enough oxygen and exhale the carbon dioxide that has collected in them. In this case, ventilators take over the functions of the respiratory system.

Timely connection to the “fan” maximizes the chances of survival. If a person who has stopped breathing is not connected to a ventilator, his/her internal organs are no longer supplied with oxygen. Soon thereafter, the heart stops beating, the blood supply stops, and within minutes the patient dies.

How do ventilators work?

The principle by which ventilators work is called positive pressure ventilation. They pump oxygenated air into the lungs and pump fluid out of them. It sounds simple, but in reality, it is a complex process. Modern ventilators have many different ventilation modes that are used depending on the specific situation.

In Pressure Controlled Ventilation (PCV) ventilation, a ventilator (respirator) creates a certain level of pressure in the airways and alveoli so that they can absorb as much oxygen as possible. As soon as the pressure reaches the set maximum limit, the exhalation mode begins. Thus, the respirator takes over the entire breathing process of the patient.

How do patients feel under ventilators?

There are two types of mechanical ventilation: invasive and non-invasive. With non-invasive artificial respiration, a tight-fitting mask is put on the patient’s face, through which air is supplied to the lungs using the ventilator. In this case, the person retains all the natural functions of the respiratory tract.

To perform invasive ventilation, the patient is intubated – a tube is inserted into the trachea through the nose or mouth. In some cases, a person needs tracheotomy: the doctor makes a small incision in the lower part of the neck to open the trachea, a tube is inserted into it, and then a ventilator is connected to it.

People connected to ventilators can neither speak, nor eat, nor drink: they have to be artificially fed through a tube. Because invasive ventilation is also quite painful, patients are usually inducted into an artificial coma using anesthesia.