In a sterilizer objects are sterilized. In the medical field, especially surgical instruments are sterilized to reduce the risk of infection. Physical sterilization is either through heat, radiation or steam.

What is a sterilizer?

In the medical field, sterilization usually takes place in physically sterilizing autoclaves which are operated with steam. The killing of microorganisms can be done via heating instead of pressure.

Medical sterilizers are used for sterility, that is the sterilization. A sterilizer frees treated areas of DNA fragments, viruses and microorganisms of all stages including their spores.

Sterilizers are usually physical sterilizers. Chemical sterilization works with toxic gases and places high demands on safety precautions. Therefore they are hardly used.

In the medical field, sterilization usually takes place in physically sterilizing autoclaves which are operated with steam. The killing of microorganisms can be done via heating instead of pressure. In addition to the medical sector, areas such as biotechnology or the food industry rely on sterilizers. While surgical instruments and other instruments are sterilized in the medical field, in biotechnology, for example, they are glassware.

The world's first steam sterilizer was invented by M. Lautenschläger at the end of the 19th century. This invention was a big step for medical sterility. Until the 19th century, little sterile medicine was used. The invention of the sterilizer thus reduced the risk of infection, sepsis and death as a result of medical treatments.

Shapes, types & types

Medical sterilizers are usually steam sterilizers. These are gas-tight sealable pressure vessels in which various materials in the overpressure range can be subjected to thermal treatments.

Most commonly, sterilization is initiated by a vacuum process. The container is pumped out several times and steam flows in. In the gravitation process, however, the air in the steam sterilizer is displaced by saturated steam. The medical steam sterilization takes place at temperatures of 121 degrees Celsius and a pressure of one bar. The materials to be sterilized are exposed to these conditions for at least 20 minutes.

Distinguish from the steam sterilizers are the easier-to-use hot air sterilization. They work with dry heat at temperatures up to 250 degrees Celsius. The sterilization time in these devices is at least 30 minutes. Radiation sterilizers are also used today and work with UV rays, electron bombardment or beta and gamma rays.

Structure & functionality

Steam sterilizers are constructed similar to the Papin pot. This tightly sealed vessel paved the way for the modern pressure cooker in the 17th century. In the hermetically sealed autoclave, the air is completely replaced by water vapor and organic cells are destroyed at high pressure. This condition is usually achieved by changing over periods between pumping down and inflow. That is, air is pumped off piece by piece and steam is let in piece by piece.

Inside the devices, a heat of at least 120 degrees Celsius is released at an overpressure of several bar and an absolutely water vapor saturated atmosphere is present. The period of time for producing a vacuum is also known as heat-up time. This process is followed by the compensation time, which serves to produce the required temperatures inside the material to be sterilized. This period is followed by an exposure time during which the germs are killed. In the cooling time, the sterile goods cool and are ventilated. Steam sterilization thus works via heating in the moist state.

In hot-air sterilizers, on the other hand, sterilization takes place by means of moving and dry hot air, which flows around the object to be sterilized and thus flares off. The hot air sterilization works with such high temperatures that it is absolutely unsuitable for paper and textiles. In radiation sterilization, in turn, ionizing radiation destroys the nucleic acids of microbial cells. All sterilizers rely on a gas-tight closed mold.

Medical and health benefits

Ever since Semmelweis, medicine has suggested that strict hygiene measures are likely to reduce deaths from surgery and other medical treatments. Until then, doctors had considered hygiene to be less relevant and operated on black coats, for example, which did not need to be washed after each operation. Also, the cleaning of the instruments and the surgical field was not common at that time.

A breakthrough came in this regard J. Lister. He used Karbol as a cleanser for the hands, the medical instruments and the surgical field. He succeeded in producing a low-germ atmosphere and thus a reduction in the risk of infection.

As soon as the microscope was used, medicine recognized the existence of pathogenic germs. Asepsis established itself as a requirement for medical procedures and instruments. The mere cleaning of instruments became the disinfection and finally the sterilization. Inventions such as sterile rubber surgical gloves were born.

From disinfection sterilization differs in claim. The goal of sterilization is 100% sterility. Although this complete sterility can not be guaranteed to date either in practices or in hospitals, the residual content of microorganisms capable of reproduction after sterilization by a whole ten-fold less than after a mere disinfection.

The medical and health benefits of sterilizers are correspondingly high. Medical sterilizers are now a basic purchase for medical institutions in the Western world, since a lack of sterility of surgical instruments and other instruments according to the findings of asepsis would be a negligent and irresponsible treatment of patient life. Tags: 

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