ISOLATION

INTRODUCTION

Isolation refers to the precautions that are taken in the hospital to prevent the spread of an infectious agent from an infected or colonized patient to susceptible persons. Isolation practices are designed to minimize the transmission of infection in the hospital, using current understanding of the way infections can transmit. Isolation should be done in a user friendly, well-accepted, inexpensive way that interferes as little as possible with patient care, minimizes patient discomfort, and avoids unnecessary use.

Isolation practices can include placement in a private room or with a select roommate, the use of protective barriers such as masks, gowns and gloves, a special emphasis on handwashing (which is always very important), and special handling of contaminated articles. Because of the differences among infectious diseases, more than one of these precautions may be necessary to prevent spread of some diseases but may not be necessary for others.

The Centers for Disease Control and Prevention (CDC) and the Hospital Infection Control Practice Advisory Committee (HICPAC) have led the way in defining the guidelines for hospital-based infection precautions. The most current system recommended for use in hospitals consists of two levels of precautions. The first level is Standard Precautions which apply to all patients at all times because signs and symptoms of infection are not always obvious and therefore may unknowingly pose a risk for a susceptible person. The second level is known as Transmission-Based Precautions which are intended for individuals who have a known or suspected infection with certain organisms.

Frequently, patients are admitted to the hospital without a definite diagnosis, but with clues to suggest an infection. These patients should be isolated with the appropriate precautions until a definite diagnosis is made.

CATEGORIES OF ISOLATION

The term strict isolation is used to describe the isolation procedure for highly transmissible and/or dangerous pathogens. The term standard isolation is used to describe methods used for other transmissible infections. The term protective isolation is used to describe methods of isolation for highly susceptible patients. The isolation categories vary from country to country. Most UK hospitals have adopted four categories, and special instructions are given by the Infection Control Team if variations are necessary. In general the patient should be isolated for the duration of the illness or until the infectious stage of the illness has passed.

Category A.

These infections are spread by; (1) hands, (2) contact with non-sterile equipment, faeces, blood and body fluids, and (3) bedpans/urinals. Viruses considered under this category include HIV, HAV, HBV, HCV, diarrhoeal viruses and enteroviruses. A cubicle or private room is required. All staff should wear a gown or apron and gloves when attending a patient. All persons should wash their hands on leaving the cubicle. Masks are not necessary but should be used if indicated. The discipline of the staff is of vital importance, especially in hand-washing, keeping the door closed, disinfection of toilets and bedpans etc. Enteric precautions are always necessary for diarrhoeal diseases and enteric fever. Staff should be protected against TB, polio, rubella and HBV.

Category B.

This category covers infections spread from the respiratory tract via droplets eg. chickenpox, measles, mumps. A cubicle or single room is essential. Masks, gloves, and aprons should be worn when handling the patient. A ventilation system (consisting of at least an extractor fan) is advantageous for patients with communicable respiratory infections, especially chickenpox.

The following general principles apply for category A and B isolation;-

1.   Room or cubicle - the door should be kept closed at all times. An extraction fan may be fitted. Any unnecessary furniture should be removed before admitting the patient. The room may be equipped with special items needed to nurse the patient eg. pedal bins, plastic bags etc. All equipment should be kept inside the room and the room should be kept tidy.

2.   Gowns and aprons- disposable aprons are recommended. Cotton gowns provide limited protection but are acceptable in most circumstances. Gowns made of water-repellent material give better protection. The gown or apron should be left hanging in the room and changed daily or earlier when soiled. Although disposable aprons are preferable, non-disposable plastic aprons may be used and should be disinfected by heat or alcohol.

3.   Gloves - gloves should be worn when handling infected material and sites and. Conventional disposable non-sterile plastic gloves are adequate for most purposes. Long sleeved disposable gloves may be used when protection of the arms is necessary.

4.   Masks - masks are necessary for category B and perhaps some category A infections; if used they should be of the high efficiency filter type, which should provide protection for 10-15 minutes.

5.   Hands - hand washing before and after contact with the patient is perhaps the most important measure in preventing the spread of infection. Either a non-medicated soap or a detergent antiseptic preparation should be adequate for most purposes. 70% alcohol is more effective in removing transient as well as residual flora and should be used in high risk situations.

6.   Bedpans and urinals - gloves should be worn when handling bedpans and urinals. The contents should be disposed of directly into the sluice or bedpan disinfector. The bedpan or urinal should then be heat disinfected and dried. A bedpan washer/disinfector and a high temperature washing-up machine should be available in the ward.

7.   Wastes - all clinical waste should be disposed of in a colour-coded bag for incineration.

8.   Equipment - disposable or autoclavable equipment should be used whenever possible. Essential items of patient care such as sphygmomanometers and stethoscopes should be left in the room and disinfected when the patient is discharged or before being used on another patient. Hard surfaces may be disinfected by wiping with a phenolic or hypochlorite solution. Other equipment may be disinfected by wiping with 70% alcohol. Sphygmomanometer cuffs may be disinfected by low temperature steam. Thermometers should be kept in the isolation room until the patient is discharged.

9.   Needles and syringes - these should be disposable and placed in a hardened container which is sealed before disposal.

10.               Linen - avoid vigorous bed-making - linen from infected patients should be placed in a colour-coded linen bag for transfer to the laundry. Linen which may present a hazard to the laundry staff eg. hepatitis B, should first be sealed in labelled bag.

11.               Crockery and cutlery - disposable items may be used when a dishwasher heating the items to over 80^oC is not available. Food should be placed in polythene bags and discarded with ward waste.

12.               Laboratory specimens - some warning should be given to the laboratory staff. Containers should be placed in a biohazard bag.

13.               Charts - patient’s charts should be kept outside the contaminated areas.

14.               Disposal of personal clothing - clean clothing requires no special treatment. Contaminated or fouled clothing should be transferred to the hospital laundry in a sealed water-soluble or alginate-stitched bag. Clothing from patients with viral hemorrhage fever require special arrangement.    

15.               Transporting patients - patients should be sent to other departments only if it is essential to do so. The department should be notified in advance so that they may take suitable measures to prevent the spread of infection

Disposal of the dead - when death of a person suffering from a notifiable infectious disease takes place in a hospital, provision is made under the Public Health Act 1936 to prohibit the removal of the body from the hospital, except for the purpose of being taken direct to a mortuary or being buried or cremated. Every step should be taken to prevent persons coming unnecessarily into contact with it. A justice of the peace has the power to order the removal or the burial of the body. In practice the above powers are not generally enforced. Cremation is the safest method of disposal and relatives should be encouraged to agree to this method although it cannot be legally enforced.

Terminal disinfection of isolation rooms - all surfaces and walls must be washed thoroughly with warm water and detergent and dried (wipe over with a disinfectant if indicated) All bed linen, curtains etc. that is sent to the laundry should be clearly marked "infected" The bed mattress and pillow should be wiped with warm water and detergent and dried thoroughly. Occasionally, a disinfectant may be indicated. All heat-sensitive items of equipment that are for common ward use should be wiped with 70% alcohol mixture. All autoclavable items should be sent to the CSSD. All disposable items should be discarded in containers for clinical waste and the room should be aired and open for admission after 24 hours. If the isolation area is a bed on an open ward, then the entire surrounding area up to the next bad, including curtains, should be treated as above.

Category C. (Reverse - Protective Isolation)

This is used for diseases in which there is increased susceptibility to infection such as patients with neutropenia, on anti-cancer chemotherapy, and severely immunocompromized patients. The amount of protection required varies with the type of patient. Essentially, such patients should be isolated with a minimum of dust, dirt, and wet areas. Hands must be washed or disinfected before entering the room. Sterile gloves, gown or apron, and masks should be worn and discarded after attending patient. Maximum protection, including sterile linen, food and other supplies, may be required for immunosuppressed patients, but is not necessary for patients with eczema and burns. Maximum protective isolation requires the use of a ventilated room or positive pressure isolator. Mouth and other orifices should be decontaminated, gut and skin may also have to be decontaminated. Staff should wear sterile protective clothing. If visitors are admitted to the isolation room, they should be given detailed instructions and if suffering from any infection, they should be excluded.  

Category D. (Strict Isolation)

Category D isolation is only found in specialized units for highly contagious infections such as rabies and viral haemorrhagic fevers. A cubicle is essential (a plastic bubble that contains the patient and all essential patient-care equipment) may be used. Gowns, plastic aprons, masks, and eye goggles should be worn. Crockery and cutlery should be disposable. Disposable non-clinical articles should be used and should not be recycled. All other clinical equipment should be sterilized. Air-borne contamination and patient-handling should be kept to a minimum. Hospital staff and visitors should be made aware of the risks when tending such patients.

SUGGESTED LABELS FOR CATEGORIES OF ISOLATION

Adhesive labels are recommended to be used for patients in isolation. These should be attached to the door of the isolation room. The labels should be held by the Ward Sister and are colour-coded.

Category A or B Isolation  

Visitors	Please report to sister’s office before entering room
Single Room	Necessary for all infections transferred by air, and preferred for other infections, door must be kept closed
Plastic Aprons	Must be worn when attending patients
Masks	Not necessary, except for persons susceptible to the disease (filter type)
Hands	Must be washed on leaving
Gloves	Not necessary (except for contact with infected area, or when excretion or secretion precautions necessary
Articles	Normal supplies. Disposed in waterproof containers
Comments

D. Strict source isolation  

Visitors	Please report to sister’s office before entering room
Single Room	Necessary, door must be kept closed
Gowns, aprons	Must be worn
Masks	Must be worn (filter type)
Hands	Must be washed on leaving
Gloves	Must be worn
Articles	Disposable supplies. Disposed in waterproof containers
Comments

The "comments" line is left blank so that the ward sister may enter details pertaining to the individual patient.

Category C. Protective isolation  

Visitors	Please report to sister’s office before entering room
Single Room	Necessary, door must be kept closed; patient must not leave the room
Gowns  (Impervious)	Must be worn
Masks	Must be worn (filter type)
Hands	Must be washed before handling the patient and his surroundings
Gloves	Must be worn by those handling the patient or with objects coming in contact with the patient
Articles	For immunosuppressed patient all items, including food should be sterile. No special precautions when removing from the room.

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ISOLATION PROCEDURE  AND CLASSIFICATION

Seven isolation categories are used in the US: Strict isolation, Contact isolation, Respiratory isolation, Enteric precautions, Blood/Body Fluid Precautions, Drainage/Secretion Precautions, and tuberculosis isolation.

1.   Strict Isolation - this is designed to prevent transmission of highly contagious or virulent infections that may be spread by air or contact. This is equivalent to the strict isolation protocol in the UK. However in the US, this is recommended for chickenpox as well as for viral haemorrhagic fevers. A private room is required and gowns, masks, and gloves must be worn before entry. Hands must be washed after leaving the room and contaminated articles should be discarded or bagged and labelled before being sent for decontamination and reprocessing.

2.   Contact Isolation - this is designed to prevent transmission of highly transmissible or epidemiologically important infections that do not warrant strict isolation. All diseases included in this category are spread primarily by close or direct contact such as HSV and respiratory infections in infants and young children. Private room is indicated although patients infected with the same organism may share a room. Masks are indicated for those who come close to the patient. Gowns are indicated if soiling is likely. Gloves are indicated for touching infective material. Hands must be washed after touching the patient or potentially contaminated articles and before taking care of another patient. Articles contaminated with infective material should be discarded or bagged and labelled.

3.   Respiratory Isolation - this is designed to prevent transmission of infectious diseases over short distances through the air. Direct and indirect contact transmission may occur but is infrequent. Diseases requiring respiratory isolation include measles, mumps, and rubella. Private room is indicated although patients infected with the same organism may share a room. Masks are indicated for those who come in close contact with the patient. Gowns and gloves are not indicated. Hands must be washed after touching the patient or contaminated articles, and contaminated articles should be discarded or bagged and labelled.

4.   Enteric Precautions - enteric precautions are designed to prevent infections that are transmitted by direct or indirect contact with faeces. Diarrhoeal viruses, hepatitis A, and enteroviruses are included in this category. A private room is indicated if patient hygiene is poor and thus at risk of contaminating others. Masks are not indicated. Gowns are not indicated if soiling is likely. Gloves should be used for touching infective material. Hands must be washed after touching the patient or contaminated articles, and contaminated articles should be discarded or bagged and labelled.

5.   Blood/body fluid precautions - blood/body fluid precautions are designed to prevent infections that are transmitted by contact with blood or other body fluids such as HIV and HBV. A private room is indicated if patient hygiene is poor because of the higher risk to others. Masks are not indicated. Gowns are only indicated f soiling is likely. Masks are not indicated but gloves should be worn. Hands must be washed after touching the patient or contaminated articles, and contaminated articles should be discarded or bagged and labelled. Care should be taken to avoid needle-stick injuries. Used needles should not be recapped or bent; they should be placed in a prominently labelled, puncture-resistant container designated specifically for such disposal. Blood spills should be cleaned up promptly with hypochlorite.

6.   Drainage/Secretion Precautions - these are designed to prevent infections that are transmitted by direct or indirect contact with purulent material or drainage from an infected body site. A private room is not indicated. Gowns are only indicated if soiling is likely. Masks are not indicated but gloves should be worn. Hands must be washed after touching the patient or contaminated articles, and contaminated articles should be discarded or bagged and labelled.