Chapter 2: Transmission based precautions (TBPs)

Contents

2.1 Patient placement/assessment of infection risk
2.2 Safe management of patient care equipment in an isolation room/cohort area
2.3 Safe management of the care environment
2.4 Personal protective equipment (PPE): respiratory protective equipment (RPE)
2.5 Aerosol generating procedures
2.6 Infection prevention and control when caring for the deceased

Standard infection control precautions may be insufficient to prevent cross transmission of specific infectious agents and additional precautions called “transmission based precautions” (TBP) may be required when caring for patients with known / suspected infection or colonisation.

Transmission based precautions are categorised by the route of transmission of infectious agents (some infectious agents can be transmitted by more than one route).

Clinical judgement and decisions should be made by staff on what additional precautions are required and this will be based on:

  • suspected/known infectious agent
  • severity of the illness caused
  • transmission route of the infectious agent
  • care setting and procedures undertaken.

Type of precautions:

Contact precautions:

Used to prevent and control infections that spread via direct contact with the patient or indirectly from the patient’s immediate care environment (including care equipment). This is the most common route of cross-infection transmission.

Droplet precautions:

Measures used to prevent, and control infections spread over short distances (at least 1 metre) via droplets from the respiratory tract of one individual directly onto a mucosal surface or conjunctivae of another individual. Droplets penetrate the respiratory system to above the alveolar level.

Airborne precautions:

Measures used to prevent, and control infection spread without necessarily having close patient contact via aerosols from the respiratory tract of one individual directly onto a mucosal surface or conjunctivae of another individual. Aerosols can penetrate the respiratory system to the alveolar level.

The traditional modes of transmission for respiratory infectious agents as defined before the COVID-19 pandemic are unlikely to be as delineated as is described in the scientific literature, ie, droplet or airborne transmission and the application of TBPs may differ depending on the setting and the known or suspected infectious agent. Applications of TBPs should be considered within the framework of the
hierarchy of controls. Setting-specific risk assessment tools are available to support organisations in applying the hierarchy of controls Coronavirus » Every action counts.

Appendix 11 provides details of the type of precautions, optimal patient placement, isolation requirement and respiratory precautions required.

Further information on transmission based precautions can be found in the definitions of transmission based precautions literature reviews.

NB During the COVID-19 pandemic universal masking in healthcare and increased physical distancing were introduced as additional infection, prevention and control (IPC) measures. These measures are not included in this version of the National infection prevention and control manual as it is currently covered by UK IPC Guidance as published by UK Health Security Agency.

2.1 Patient placement / assessment of infection risk

The potential for transmission of infection must be assessed when a patient enters a care area. If hospitalised/in a care home setting, this should be continuously reviewed throughout the stay/period of care. The assessment should influence patient placement decisions in line with clinical/care need(s).

Patients who may present a cross-infection risk in any setting includes those:

  • with diarrhoea, vomiting, an unexplained rash, fever or respiratory symptoms
  • known to have been previously positive with multidrug-resistant organisms (MDRO) eg methicillin-resistant staphylococcus aureus (MRSA), carbapenemase-producing enterobacterales (CPE)
  • who have been an inpatient in any hospital in the UK or abroad or are a known epidemiological link to a carrier of CPE
  • who have a known or suspected infection or colonisation.

Isolation facilities should be prioritised depending on the known/suspected infectious agent (refer to the aides memoire in this document – appendices 11a and 11b).

All patient placement decisions and assessment of infection risk (including isolation requirements) must be clearly documented in the patient notes and provided in patient handovers with other healthcare/care providers.

The clinical judgement and expertise of the staff involved in a patient’s management and the infection prevention and control team (IPCT) should be sought, particularly for the application of TBPs, eg isolation prioritization, when single rooms are in short supply.

Single room isolation in hospital settings:

  • isolation of infectious patients can be in specialised isolation facilities, single room isolation, cohorting of infectious patients where appropriate, ensuring that they are separated by at least 3 feet (1 metre) with the door closed
  • signage should be used on doors/areas to communicate isolation requirements and prevent entry of unnecessary visitors, non-essential staff
  • patient confidentiality must be maintained
  • infectious patients should only be transferred to other departments if clinically necessary. If the patient has an infectious agent transmitted by the airborne/droplet route, then if possible/tolerated the patient should wear a surgical face mask in communal areas during transfer
  • receiving department/hospital and transporting staff must be aware of the necessary precautions
  • isolation room doors should remain closed, if this is not possible, eg paediatrics, there should be a documented risk assessment.

Single room isolation in care settings with or without nursing care:

  • Residents should remain in their bedroom while considered infectious and the door should remain closed (if unable to isolate this should be documented).
  • If transfer to hospital is required, ambulance services and the hospital admission area should be informed of the infectious status of the resident. Advice on resident’s clinical management should be sought from the GP and the local health protection unit infection prevention team.
  • Avoid unnecessary transfer of residents within/between care areas.

Primary care/outpatient settings:

Patients attending with suspected/known infection/colonisation should be prioritised for assessment/treatment, eg scheduled appointments at the start or end of the clinic session.

Infectious patients should be separated from other patients while awaiting assessment and during care management by at least 3 feet (1m).

If transfer from a primary care facility to hospital is required, ambulance services should be informed of the infectious status of the patient.

Staff cohorting: consider assigning a dedicated team of care staff to care for patients in isolation/cohort rooms/areas as an additional infection control measure during outbreaks/incidents. This can only be implemented if there are sufficient levels of staff available (so as not to have a negative impact on non-affected patients’ care).

Before discontinuing isolation:

Individual patient risk factors should be considered (eg there may be prolonged
shedding of certain microorganisms in immunocompromised patients).

2.2 Safe management of patient care equipment in an isolation room/cohort area

  • Use single-use items if possible.
  • Reusable non-invasive care equipment should be dedicated to the isolation room/cohort area and decontaminated prior to use on another patient.
  • An increased frequency of decontamination should be considered for reusable non-invasive care equipment when used in isolation/cohort areas.
  • For how to decontaminate non-invasive reusable equipment see Appendix 7.

2.3 Safe management of the care environment

The care environment must be:

Equipment used for environmental decontamination must be either single-use or dedicated to the affected area then decontaminated or disposed of following use eg cloths, mop heads.

Environmental decontamination: enhanced cleaning

Refer to the National Cleaning Standards for enhanced cleaning in different settings.

Inpatient settings:

Patient isolation/cohort rooms/area must be decontaminated at least daily, this may be increased on the advice of IPCTs/. These areas must be decontaminated using either:

  • a combined detergent/disinfectant solution at a dilution of 1,000 parts per million available chlorine (ppm available chlorine (av.cl.)); or
  • a general-purpose neutral detergent in warm water followed by solution of 1,000ppm av.cl.

Alternative cleaning agents/disinfectant products may be used with agreement of the local IPC team.

Employers must ensure that cleaning products and protocols are managed and risk assessed in accordance with the COSHH regulations – control of substances hazardous to health (COSHH) – health and safety topics in cleaning.

Manufacturers’ guidance and recommended product ‘contact time’ must be followed for all cleaning/disinfection solutions.

Increased frequency of decontamination/cleaning schedules should be incorporated into the environmental decontamination schedules for areas where there may be higher environmental contamination rates, eg:

  • toilets/commodes particularly if patients have diarrhoea; and
  • “frequently touched” surfaces eg door/toilet handles, locker tops, over bed tables and bed rails.

Vacated rooms should also be decontaminated following an AGP. Clearance of infectious particles after an AGP is dependent on the ventilation and air change within the room. This is a minimum of 20 minutes in hospital settings where the majority of these procedures occur. In general wards and single rooms there should be a minimum of 6 air changes per hour, in negative-pressure isolation rooms there should be a minimum of 10 air changes per hour. Advice should be sought from IPCT.

Primary care/outpatient settings:

The extent of decontamination between patients will depend on the duration of the consultation/assessment, the patients presenting symptoms and any visible environmental contamination.

Terminal decontamination

Following patient transfer, discharge, or once the patient is no longer considered infectious, remove from the vacated isolation room/cohort area, all:

  • healthcare waste and any other disposable items (bagged before removal from the room)
  • bedding/bed screens/curtains – manage as infectious linen (bagged before removal from the room)
  • reusable non-invasive care equipment (decontaminated in the room prior to removal) Appendix 7.

The room should be decontaminated using either:

  • a combined detergent disinfectant solution at a dilution (1,000ppm av.cl.); or
  • a general-purpose neutral detergent in warm water followed by a solution of 1,000ppm av.cl. (or alternative locally agreed cleaning product).

Rooms must be cleaned from highest to lowest points and from least to most contaminated points.

Organisations can consider using hydrogen peroxide vapour disinfection or ultraviolet light technology for specific pathogens. Manufacturers’ guidance and recommended product “contact time” must be followed for all cleaning/disinfection solutions.

There is no requirement for terminal cleaning of outpatient/theatre recovery unless advised by the IPCT.

2.4 Personal protective equipment (PPE): respiratory protective equipment (RPE)

Personal protective equipment (PPE) must still be used in accordance with SICPs when using respiratory protective equipment (RPE). See Chapter 1.4 for PPE use for SICPs.

Where it is not reasonably practicable to prevent exposure to a substance hazardous to health (as may be the case where healthcare workers are caring for patients with suspected or known airborne pathogens), the hazard must be adequately controlled by applying protection measures appropriate to the activity and consistent with the assessment of risk.

If the hazard is unknown the clinical judgement and expertise of IPC staff is crucial and the precautionary principle should apply.

Respiratory protective equipment (RPE) ie, a filtering face piece (FFP) must be considered when a patient is admitted with a known/suspected infectious agent/disease spread wholly or partly by the airborne route and when carrying out aerosol generating procedures (AGPs) on patients with a known/suspected infectious agent spread wholly or partly by the airborne or droplet route.

Staff in primary care/outpatient settings or care homes would not normally be required to wear an FFP3 respirator for routine care unless an AGP is being performed on an infectious patient in which case staff should wear a fit tested, FFP3 respirator.

The decision to wear an FFP3 respirator should be based on clinical risk assessment eg task being undertaken, the presenting symptoms, the infectious state of the patient, risk of acquisition and the availability of treatment.

For a list of organisms spread wholly or partly by the airborne (aerosol) or droplet routes see Appendix 11a.

National Priority Risk Categorisation for fit testing with FFP3 respirators

The following risk categorisation is the minimum requirement for staff groups that require FFP3 respirator fit testing. Healthcare organisations can add to this, for example where there are high risk units. This categorisation is inclusive of out of hours services.

Level 1 – Preparedness for business as usual

Staff in clinical areas most likely to provide care to patients who present at healthcare facilities with an infectious pathogen spread by the airborne route; and/or undertake aerosol generating procedures ie, A&E, intensive care unit, paediatrics, respiratory, infectious diseases, anaesthesia, theatres, chest physiotherapists, special operations response team (ambulance), A&E, ambulance staff, bronchoscopy staff, resuscitation teams, mortuary staff.

Level 2 – Preparedness in the event of emerging threat

Staff in clinical settings likely to provide care to patients admitted to hospital in the event of an emerging threat eg medical receiving, surgical, midwifery and specialty wards, all other ambulance transport staff. In the event of an ‘epidemic/pandemic’ local assessment as per organizations preparedness plans apply.

FFP3 respirator or powered respirator hood:

  • may be considered for use by visitors if there has been no previous exposure to the infected person or infectious agent; but
  • must never be worn by an infectious patient(s) due to the nature of the respirator filtration of incoming air not expelled air
  • powered respirator hoods are an alternative to tight-fitting FFP3 respirators for example when fit testing cannot be achieved
  • powered hoods can be single use (disposable) or reusable (with a decontamination schedule, see note) and must be fluid resistant; the filter must be enclosed with the exterior and the belt able to withstand disinfection with 10,000ppm av.cl.
  • respirators and powered respirator hoods with exhalation vales are ineffective for source control. These should not be won by a healthcare worker/operator when sterility directly over the surgical field is required eg in theatres/surgical settings or when undertaking a sterile procedure (see National Patient Safety Alert).

All tightfitting RPE ie, FFP3 respirators must be:

  • single-use (disposable) or reusable, and worn with a full face visor if not classed as fluid-resistant by the manufacturer (EN149)
  • fit tested on all healthcare staff who may be required to wear a respirator to ensure an adequate seal/fit according to the manufacturers’ guidance
  • fit checked (according to the manufacturers’ guidance) every time a respirator is donned to ensure an adequate seal has been achieved
  • compatible with other facial protection used ie protective eyewear so that this does not interfere with the seal of the respiratory protection. Regular corrective spectacles are not considered adequate eye protection.

HSE guidance and demonstrations for putting on respirators and performing a fit check is available here.

For any facial hair, the hair must not cross or interfere with the respirator sealing surface. If the respirator has an exhalation valve, hair within the sealed mask area should not impinge upon or contact the valve. You must pass a face fit test for any tight-fitting respiratory protective equipment that you need to use for work activities. Examples of facial hair styles that are compatible with FFP3 respirators can be found here.

Please note: Any respirator, including reusable respirators/powered respirator hoods must comply with HSE guidance (HSG53) and be adequate and suitable for their intended use. Reusable respirators must have a decontamination schedule in place and be maintained according to manufacturer’s instructions.

Further information regarding fitting and fit checking of respirators can be found on the Health and Safety Executive website.

Removal (doffing) of PPE

  • in the absence of an anteroom/lobby remove FFP3 respirators and eye/face protection in a safe area (eg outside the isolation/cohort room/area)
  • all other PPE should be removed in the patient care area.

For the recommended method of putting on and removing PPE, see UK Health and Safety Agency guides.

Further information can be found in respiratory protective equipment (RPE) literature review and PPE for infectious diseases of high consequence (IDHC) literature review.

2.5 Aerosol generating procedures

Aerosol generating procedures (AGPs) are medical procedures that can result in the release of aerosols from the respiratory tract. The criteria for an AGP are a high risk of aerosol generation and increased risk of transmission (from patients with a known or suspected respiratory infection).

The list of medical procedures that are considered to be aerosol generating and associated with an increased risk of respiratory transmission is:

  • awake* bronchoscopy (including awake tracheal intubation)
  • awake* ear, nose, and throat (ENT) airway procedures that involve respiratory suctioning
  • awake* upper gastro-intestinal endoscopy
  • dental procedures (using high speed or high frequency devices, for example ultrasonic scalers/high speed drills)
  • induction of sputum
  • respiratory tract suctioning**
  • surgery or post-mortem procedures (like high speed cutting / drilling) likely to produce aerosol from the respiratory tract (upper or lower) or sinuses
  • tracheostomy procedures (insertion or removal).

*Awake including ‘conscious’ sedation (excluding anaesthetised patients with secured airway).

** The available evidence relating to respiratory tract suctioning is associated with ventilation. In line with a precautionary approach, open suctioning of the respiratory tract regardless of association with ventilation has been incorporated into the current (COVID-19) AGP list. It is the consensus view of the UK IPC cell that only open suctioning beyond the oro-pharynx is currently considered an AGP, that is oral/pharyngeal suctioning is not an AGP.

2.6 Infection prevention and control when caring for the deceased

The principles of SICPs and TBPs continue to apply while deceased individuals remain in the care environment. This is due to the ongoing risk of infectious transmission via contact although the risk is usually lower than for living patients.

Staff should advise relatives of the precautions following viewing and/or physical contact with the deceased and also when this should be avoided.

Washing and/or dressing of the deceased should be avoided if the deceased is known or suspected to have an invasive streptococcal infection, viral haemorrhagic fevers or other hazard group 4 infectious agents. See Appendix 11b.

Deceased patients with a suspected or confirmed hazard group 4 pathogen should be transferred to a specialised high consequence infectious disease (HCID) facility as part of the HCID response network.

Deceased individuals known or suspected to have a hazard group 4 infectious agent should be placed in a sealed double plastic body bag with absorbent material placed between each bag. The surface of the outer bag should be disinfected with 1000ppm av.cl before being placed in a robust sealed coffin.

Post-mortem examination should not be performed on a deceased individual known or suspected to have hazard group 4 infectious agents. See Appendix 11b. Blood sampling can be undertaken in the mortuary by a competent person to confirm or exclude this diagnosis. Refer to section 2.4 for suitable PPE.

Refer to HSG283 – managing infectious risk when handling the deceased for more information.

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