University Malaya Medical Centre
Additional Precautions are used when Standard Precautions (as discussed in the last bulletin) are no longer adequate to prevent transmission of infections. Standard and Additional Precautions are used for patients known or suspected to be infected or colonised with epidemiologically important or highly transmissible pathogens that can cause infections:
- by airborne transmission (e.g. Mycobacterium tuberculosis, Measles, Chicken pox)
- by droplet transmission (e.g. Mumps, Rubella, Pertussis, Influenza)
- by direct or indirect contact with dry skin (e.g. colonisation with MRSA) or with contaminated surfaces
- By any combinations of these routes
Additional "Transmission-based" Precautions are designed to interrupt transmission of infection by these routes and should be used in addition to Standard Precautions. This two-tiered approach to infection control should provide high level of protection to both patients and health-care workers in all healthcare settings.
Additional precautions are not required for patients with blood-borne viruses such as HIV, Hepatitis B or Hepatitis C unless there are complicating factors present, such as pulmonary tuberculosis.
Situations in which Additional Precautions should also be considered include the following:-
- Procedures on patients with aerosol or airborne disseminating condition e.g. chickenpox, tuberculosis
- Unusual manifestations of sepsis, including those by MRSA or multi-drug resistant organisms.
- Patients who may be immunocompromised e.g. with immune suppression induced by chemotherapy
- Patients in high level of care units, such as in renal dialysis, burn units or bone-marrow transplant units
- Patients who may be gross disseminators of micro-organisms (e.g. patients with large areas of infected skin or large open or discharging purulent wounds) should be placed in a single room
Empiric Use of Airborne, Droplet or Contact Precautions
In many instances, the risk of nosocomial transmission of infection may be highest before a definitive diagnosis can be made and before precautions based on that diagnosis can be implemented. The routine use of Standard Precautions for all patients should reduce greatly this risk for conditions other than those requiring Airborne, Droplet or Contact Precautions. While it is not possible to prospectively identify all patients needing these enhanced precautions, certain clinical syndromes and conditions carry a sufficiently high risk to warrant the empiric addition of enhanced precautions while a more definitive diagnosis is pursued.
Appropriate patient placement is a significant component of isolation precautions. Patients with highly transmissable infections or colonisation should be placed if possible in a single room with handwashing and toilet facilities, to reduce opportunities for transmission of micro organisms. Staff caring for these patients should have access to plastic aprons/gowns and gloves. Hands should be washed before and after attending to patient, that is, after removable of gloves and prior to leaving the patient area. Plastic aprons and gloves should be removed and disposed of immediately after use. Wear masks during invasive procedures or when patients have open respiratory infections.
Patients on Airborne Precautions (e.g. active Pulmonary Tuberculosis) require a private room with appropriate negative pressure ventilation with a minimum of 6 12 air changes per hour. Restricted movement of visitors, patients and healthcare workers should be enforced. Staff attending to these patients should wear a high efficiency particulate air filtered mask (1 micron filtration) especially during procedures such as intubation, bronchosopy, tracheostomy and suctioning.
When a private room is not available, an infected patient may be placed with an appropriate roommate with the same microorganism provided they are not infected with other potentially transmissable microorganisms and the likelihood of re-infection with the same organism is minimal. Such sharing of rooms, also referred to as cohorting patients, is useful especially during outbreaks or when there is shortage of single rooms.
It is important to consider the epidemiology and mode of transmission of the infecting pathogen before determining patient placement. Under these circumstances, consultation with infection control professionals is advisable.
Garner JS Guideline for isolation precautions in hospitals.
Infect Control Hospital Epidemiology 1996: 17:53-80
National Health and Med. Research Council and the Australian National Council on AIDS, Infection Control in the Health Care Setting April 1996
G.A. Ayliffe, A. Hambraeus, S. Mehtar, Members of the International Federation of Infection Control Education Working Group, Education Programme for Infection Control Basic Concepts and Training 1995
Monash Medical Centre Infection Control Manual. Blood and Body Substance Precautions, 1996
Infection Watch is aimed at stimulating discussion between hospital doctors and microbiologists. Comments are invited. For this issue, plese direct them to Sr Habibah A. Molok, Infection Control Unit, University Hospital, Kuala Lumpur. Tel:7502576 or 7502012
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