Medical practice is being followed from prehistoric times. Written evidences have been found that 2500 years ago it was practiced in Greece, India and other ancient civilizations. Hippocrates, Herophilus , Charak, Sushrut are some of the famous ancient physicians. The doctors have to gain knowledge of human anatomy, different diseases and medicines. However, besides knowledge and skill, modern medical care has become technology oriented. Technology has been developed to aid the doctors for cure of patients from various diseases. For this a special branch called medical technology has been developed.

In a modern hospital one can find sophisticated medical equipment in departments of radiology and pathology, and also at the operation theaters. One of the most important places in the hospital where technology is abundantly used is Intensive Care Unit (ICU). A modern ICU is mostly gadget oriented area in the hospital. Mostly critical patients were transferred to the ICU. Here, there are different equipment to monitor patient’s heart beat, cardiac output, breathing rate, blood pressure, blood oxygen levels etc. One of the most important equipment in the ICU is ventilator.

Ventilator is also called artificial respirator. When a patient feels difficulty in breathing, ventilator is used for his breathing. It is often called “life support machine” as it supports one of the most basic life functions i.e. breathing. If breathing stops for a while, a person dies. A ventilator literally breathes life into a patient.

Respiratory System:- Before knowing the principle of ventilator, let us discuss in brief the purpose of breathing & its system in human life. This system is called Respiratory System. It consists of nasal passage, wind pipe, lungs and the respiratory muscles.

Air is pumped into and out of the lungs due to expansion and contraction of lungs. During breathing air is pumped into lungs. Oxygen from the air is absorbed by blood. Oxygen is required to purify the blood. Carbon dioxide is released from blood. During breathing out carbon dioxide – dominated air is released to the atmosphere.

Ventilator:- A ventilator is an automatic machine designed to mechanically move breathable air into and out of the lungs of a patient who is physically unable to breathe properly. If due to infection of lungs or any other reason, one feels difficulty in breathing, then doctors immediately put him on ventilators. Earlier ventilators have pneumatic system in which the movement of a piston in a cylinder pushes a fixed volume of air and oxygen mixture into the patient’s lungs and inflates them. When the pressure is released, the patient breathes out due to the elasticity of lungs.

In modern ventilator, the pneumatic system has been replaced by a turbo-pump and the whole operation is controlled by a microprocessor system. As a result, this delivers the required oxygen-air mixture precisely. It has also facility for the operator to adjust the volume, pressure, flow and time interval of the ventilator breaths. The operator can also set limits for the pressure, volume and breathe rate so that these parameters can not breach the safe limits. It also displays these parameters graphically on a screen. It operates on electricity and if there is a power failure, it works on    back-up battery. It is also portable.

Although a life saving machine, the ventilator has its own limitations. Firstly, it can provide temporary breathing support. It itself does not cure anything. So the cause of breathing problem has to be diagnosed and the disease should be cured as early as possible. It will be futile to put a patient on a ventilator if the underlying disease has no chance of recovery. Secondly the process of breathing through ventilator is not natural and may injure the lungs. The tube is put in the patient’s wind pipe and it may cause lung infection.

In spite of all, ventilator saves lives. It is an important kit in the hand of doctors.