INFECTION CONTROL 16

Disposal by Incineration

This is the preferred method of disposal for all combustible and other material of an infectious nature (e.g., contaminated needles, plastic syringes and clinical waste).

      Disposable linen and infected protective clothing and drapes should be incinerated
.

VIRUS INFECTIONS IN SURGERY 

HEPATITIS B (SERUM HEPATITIS)

This is one of the most infective viruses.

•     It may be transmitted from patient to patient by as little as 0.0001 ml of infected blood.

•     The virus remains active for up to 6 months in dried blood, consequently instruments which have been poorly cleaned or disinfected may be responsible for infecting other patients, whilst poor surgical technique may result in the doctor becoming infected from the patient, or vice versa

•     It has been estimated that there are possibly 200 million carriers of hepatitis in the world, representing up to 20 percent of the population in African, Pacific, and other Tropical countries, and 0.5 percent of the population in Northern Europe. The current prevlance in the population is from
1 to 15.8 percent

•     Thus, statistically the doctor has a 1 in 200 chance of treating a hepatitis B carrier

•           If the doctor becomes accidentally infected with the hepatitis B virus, not only may the disease develop but the doctor may become a hepatitis B carrier and be an unacceptable risk to patients and may have to give up surgery. The transmission role in case of needle stick is 6 to 37 percent.

Any questions be sent to drmmkapur@gmail.com
All older posts are stored in archives for access and review.
Visitors that follow may post contributions to the site.
To create consumer/provider engagrmrnt visit www.surgseminar.blogspot.com
www.drmmkapur.blogspot.com

INFECTION CONTROL 15

Sterilization by Ionizing Radiation

Most equipment available prepackaged from the manufacturer has been sterilized by ionizing radiation. 

Items such as sutures, sponges and disposable drapes are just a few of the many types of presterilized products available. 

Also included are anhydrous materials such as powders and petroleum goods.

Sterilization by Low-Temperature Steam and Formaldehyde (LTSF)

This is a physicochemical method which uses a combination of dry saturated steam and formaldehyde to kill vegetative bacteria, bacterial spores and most viruses and the method is thus suitable for heat-sensitive materials and items of equipment with integral plastic components susceptible to damage by other processes.

            Prior to removal of sterilized objects all formaldehyde must be removed to provide a dry, sterile, formalin-free load.

Any questions be sent to drmmkapur@gmail.com

All older posts are stored in archives for access and review.

Visitors that follow may post contributions to the site.

To create consumer/provider engagement visit www.surgseminar.blogspot.com

www.drmmkapur.blogspot.com  

INFECTION CONTROL 14

Sterilization Control

•     A chemical monitor is an object that is treated with material that changes its characteristics when sterilized. This may be in the form of special ink that is impregnated into paper strips or tape and placed on the outside of the package, or it may be a substance that is incorporated into a pellet contained in a glass vial

•     The chemical responds to conditions such as extreme heat, pressure, or humidity but does not take into consideration the duration of exposure, which is critical to the sterilization process

•     Another monitoring method used to evaluate the steam sterilizer is the combined temperature time graphs that are installed within the control panel of the sterilizer. These graphs provide a permanent written record of all loads that have been processed

•     The surest way to determine the sterility of given items is with the use of biologic controls. A strain of a highly resistant, nonpathogenic, spore-forming bacteria contained in a glass vial or a strip of paper is placed in the load of goods to be sterilized. For steam sterilization, the dry spores of the bacteria Bacillus stearothermophilus are used. The gas sterilization process uses the bacterium Bacillus subtilis. The vial or strip is recovered at the end of the sterilization process and cultured. This process is time consuming and the results method of testing the efficacy of a sterilization process. Biologic controls should be administered at least once weekly. If feasible, they should also be used whenever an artificial implant or prosthesis is sterilized and the item withheld from use until the results are known to be negative.

Any questions be sent to drmmkapur@gmail.com

All older posts are stored in archives for access and review.

Visitors that follow may post contributions to the site.

To create consumer/provider engagement visit www.surgseminar.blogspot.com

www.drmmkapur.blogspot.com   

INFECION CONTROL 13

TYPES OF STERILIZERS

Gravity displacement sterilizer  The gravity (or “downward”) displacement sterilizer uses the principle that air is heavier than steam. Within the sterilizer there is an inner chamber where goods are loaded and an outer jacket type chamber that ejects steam forcefully into it. Any air in the inner chamber blocks the passage of pressurized steam to the surface of the goods and thus prevents sterilization. All the air must be removed because every surface of the supplies must be exposed to the pressurized steam to ensure sterilization. Therefore, the sterilizer is constructed in such a way that air is pushed downward by gravity (hence the name “gravity displacement sterilizer”).

Prevacuum sterilizer  The prevacuum sterilizer does not rely on gravity to remove air from the inner chamber. Instead, the air is pulled out of the chamber, which creates a vacuum in the chamber. Steam is injected into the chamber to replace the air. This type of sterilizer offers greater steam penetration in a shorter time than the gravity displacement sterilizer.

Flash sterilizer  The flash sterilizer has traditionally been used in the operating room and in other areas of the hospital to quickly sterilize items that are unwrapped. It has been common practice to flash sterilize any instrument that had become contaminated during surgery.

Any questions be sent to drmmkapur@gmail.com
All older posts are stored in archives fo access and review.
Visitors that follow may post contributions to the site.
To create consumer/provider engagement visit www.surgseminar.blogspot.com
www.drmmkapur.blogspot.com

INFECTION CONTROL 12

The Cycle of Operation

For a high-vacuum/high-pressure sterilizer, this can be summa­rized as follows:

      After loading the chamber and closing the door. The stages of autoclaving are:

•     Stage-1 Pre-vacuum—Air removal. The air is removed from the chamber by a vacuum pump and controlled steam pulsations. The vacuum achieved should be in the order of 0.5 mm Hg absolute (0.066 to 0.132 kPa).

•     Stage-2 Sterilization—Hold period at operating temperature. Steam is admitted to the chamber and when all parts of the load have reached a temperature of 134 degree C this is maintained for 3.5 minutes

•     Stage-3 Drying—Achieved by an adequate post vacuum, checked periodically by a test pack of towels which when removed from the sterilizer, unfolded and allowed to cool are not damp

•     Stage-4 Breaking the vacuum—Air replacement. This should be completed within 3 minutes, through a glass fiber or ceramic type filter

      The chamber is unloaded and the packs marked with the batch number of that particular load. Preset trays should have a water repellent or plastic dust cover applied if they are to be stored for more than a few hours. This cover should be applied only after the trays have cooled off.

      The recommended combination of time and temperature varies, and for instruments which can withstand moist heat under pressure the following cycles are recommended:

•     134°C (30 lb/in2) for a hold time of 3 minutes

•     121°C (15 lb/in2) for a hold time of 15 minutes.

Any questions be sent to drmmkapur@gmail.com

All older posts are stored in archives for access and review.

Visitors that follow may post contributions to the site

To create consumer/provider engagement visit www.surgseminar.blogspot.com

www.drmmkapur.blogspot.com 

INFECTION CONTROL 11

 Steam is the gaseous form of water. If it is to sterilize effectively, which means killing all spores:

• It must be at an appropriate temperature (which implies an appropriate pressure).

• It must be saturated with steam.

• Thus not be mixed with air, so it must displace all the air in the chamber of the autoclave.

• And, it must reach all parts of the load. If it contains droplets of water, it will soak into porous materials.

If no air is discharged, the bottom of the chamber may be much cooler than the top.

As soon as the chamber of an autoclave is full of steam at the desired temperature and pressure, it must be held there for a critical time—the holding time. The standard holding time is 15 minutes, at 121 degree C, but you may need to vary it.

Single walled autoclaves are strong metal chambers with water in the bottom, like large pressure cookers. They have several disadvantages.

This is by far the most efficient method of sterilization for materials that will stand up to heat and moisture.

Any questions be sent o drmmkapur@gmail.com 

All older posts are stored in archives for access and review.

Visitors that follow may post contributions to the site.

To create consumer/provider engagement visit www.surgseminar.blogspot.com

www.drmmkapur.blogspot.com 

INFECTION CONTROL 10

Autoclaves

This is the most efficient method of sterilizing instruments, packs and dressings, and is suitable for most materials. An autoclave is basically a pressure cooker and in fact, there is no reason why a domestic pressure cooker should not be used to sterilize instruments in a small clinic. The small autoclaves produced for the doctor’s surgery offer a choice of temperatures, pressures and sterilizing times.

      The highest temperature that can be reached by boiling water at sea level in an open vessel is 100 degree C. With increased pressure, the water can be raised to much higher temperatures before it boils, e.g. at a pressure of 0.35 kg per cm2 (5 psi) the temperature reaches 105.5 degree C: at 0.7 kg per cm2 (10 psi). 115 degree C; and at 1.05 kg per cm2 (15 psi) the temperature will reach 121 degree C, etc.

      In a sterilizer chamber (autoclave) which has been well exhausted of air the steam entering promptly fills the free spaces surrounding the load. As steam contacts the cool outer layers of the fabrics a film of steam condenses, leaving a minute quantity of moisture in the fibers of the fabrics. Air contained in the fabric interstices, being heavier than steam, is displaced by gravity in a downward direction, and the latent heat given off during the process of condensation is absorbed by that layer of the fabrics (Fig. 1.15).

      The next film of steam immediately fills the space created when the first film condensed into water, and it does not condense on the outer layer of the fabrics but penetrates into the second layer, condenses and heats it. This process continues until the whole load is heated through and no further condensation occurs, the temperature within the pack remaining at that of the surrounding steam.

•     ‘Quick’cycle would heat the water to 134 degree C (273 degree F)  for 3.5 min under a pressure of 30 lb/in2.

•     Slower cycle, more suitable for plastics, would heat the water to 121 degree C under a pressure of 15 lb/in2 15 minutes.

•     In practice, instruments are placed in the trays or in packs, the autoclave turned on, and left for the desired time.

•     At the end of the cycle, the instruments are ready for use.

•     The main disadvantage of the smaller autoclave is that instrument packs cannot be sterilized as there is not a vacuum cycle to extract air and dry the packs. However, most materials including rubber, plastics and metal can be readily sterilized, the only exception being sealed containers.

Any questions be sent to drmmkapur@gmail.com

All older posts are stored in archives for access and review.

Visitors that follow may post contributions to the site.

To create consumer/provider engagement visit www.surgseminar.blogspot.com

www.drmmkapur.blogspot.com