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Organising Outpatient Parenteral Antibiotic Therapy services


From its inception Outpatient Parenteral Antibiotic Therapy (OPAT) has been shown to be a safe and effective method of delivering healthcare

Mark Gilchrist
Lead pharmacist
Infectious Diseases

Frances Sanderson
Infectious diseases

Administering parenteral antibiotics in an outpatient setting was first described in the United States in 1974 for the management of paediatric cystic fibrosis.[1] Over recent decades this model of care termed Outpatient (or Home) Parenteral Antibiotic Therapy (O(H)PAT) has become a standard treatment option in North America,[2] Australiasia[3],[4] with Europeand especially the United Kingdom[5]-[9] looking to OPAT as an effective and efficient method of treatment.

OPAT involves the administration of intravenous or intramuscular anti-infective agent(s) without the patient having to stay overnight in hospital. Treating patients using OPAT has many advantages including increasing patients quality of life,[10] reducing inpatient hotel costs[11]-[13] and avoiding cross transmission of Methicillin-Resistant Staphylococcus aureus and other resistant organisms to the patient or from the patient to other inpatients.

These advantages together with recent once daily anti-infectives and advancing line technology make OPAT an appealing option for medical institutions and patients alike.

This short article describes areas to consider when establishing an OPAT service within the United Kingdom.

Where to start?
One of the first tasks will be to establish who are the key stakeholders in a potential OPAT service in your organisation. Some of these individuals or groups will be instrumental in driving the service and identifying target patient populations. Others will be key in managing risk, costs, secondary-primary care interfaces and policies. The make up of this group will be dependant on the local needs of the service, however key
members to include in intial discussions are:[14]-[15]

  • Consultant in microbiology/infectious diseases or other consultant physican with an interest in managing infection.
  • Clinical Nurse Specialist/ Community Nursing teams.
  • Chief Pharmacist/ Specialist Clinical or Infectious Diseases Pharmacist.
  • Hospital General Managers.
  • Hospital Finance.
  • Primary Care Trust/ Healthcare Commissioners.
  • Clinical Governance Department.
  • Patients.

The second area to consider is what type of patients the OPAT service is going to treat. Infections suitable for OPAT generally fall into three categories:
1. Short term therapy for example superficial skin infections (2-5 days).
2. Medium term therapy for example complicated urinary tract infections (10-14 days).
3. Long term therapy for example endocartitis, prothetic joint infection, diabetic foot infections, complicated skin and soft tissue infections and osteomyelitis (2-3 months or more).

A business case will generally rest on projecting a reduction in length of stay so examining this area is a good starting point. Hospital finance departments are critical in ensuring service income versus expenditure and any potential cost savings are properly evaluated.

Coding data can be a valuable source of information; extracting patient episodes coded with for example cellulitis or osteomyelitis as the primary diagnosis can give estimates for the average length of stay and the number of bed days that might be saved if an OPAT service were introduced.

An alternative might be to use data from existing OPAT services to draw conclusions about the potential in your own hosptial.

Figures 1 and 2 give a breakdown of treatment days (so potential bed days saved) and patient episodes by condition treated by our hospital’s OPAT service in 2008-09. The service takes both general medical referrals and referrals from tertiary care specialties such as oncology, orthopaedics, neurosciences and vascular surgery.


How can OPAT be delivered?
There are a variety of models used to deliver OPAT. The optimal format will depend on the local needs of the organisation, the demographics of the population and the availability and training of community nursing services. Almost without exception a clinical nurse specialist will be the appropriate person to have key responsibility for the service.

OPAT delivery models include:

  • A centralised service led by specialist Infectious Diseases or Microbiology teams dealing with a wide range of infections with the accent on reducing inpatient stay. These services will usually hold weekly multidisciplinary meetings and weekly or bi-weekly consultant led clinics.
  • A service led by a specific department (eg, the emergency department or acute admissions unit). These services usually focus on superficial soft tissue infection and may allow admissions to be avoided altogether.

With either model there is a choice of individuals
and mechanisms for delivering therapy. These include:

  • Daily attendance at the OPAT unit (only feasible in the longer term if the patient’s journey to hospitalis short).
  • Community, district nursing or private nursing companies at home.
  • Self administration; this can be a convenient and safe option if correct teaching protocols are in place.

Managing Risk
Moving the management of patients outside the confines of a ward setting strikes some as a risky practice. However, there is growing evidence that OPAT is safe and effective when properly organised even when patients practice self administration.[16]-[18]

A typical OPAT patient
OPAT is obvisouly not for everyone and each service will have their own inclusion and exclusion criteria. In general, a typical OPAT patient should:[15]

  • Have an infection that is not life threatening.
  • Have an infection that is responding to therapy.
  • Be medically stable other than their infection.
  • Have a safe home environment and support.
  • Be able to return to hospital if needed.

Choosing which anti-infectives are suitable for OPAT?
Discussions surrounding suitable anti-infectives should take place between nursing, pharmacy and medical staff at an early stage as not all anti-infectives are appropriate for OPAT. Hospitals may need to consider making new applications to their local formularies for newer once daily agents which lend themselves to OPAT. In general OPAT agents should be:

  • Well tolerated.
  • Have few side-effects.
  • Have a long half life/require infrequent administration.
  • Be administered by bolus where possible or <30 minute infusion.

The favoured antibiotic agents currently available in the
United Kingdom are:
ceftriaxone, ertapenem, tigecycline, and teicoplanin for which OPAT dosing guidelines were published earier this year.[19] Meropenem is particuarly effective for patients who can self administer. Daptomycin has recently received a license for a 2 minute bolus which will aid OPAT treatment of gram positive infections.[20]Other anti-infectives including antiviral and antifungals may be used when sensitivities dictate.

Vascular Devices
Short term therapy (less than seven days) is conveniently
accomplished with a peripheral cannula (often left for 3 days at a time) or butterfly needle (inserted for each infusion/bolus). For longer-term therapy peripherally inserted catheters with tip placement in the subclavian vein (midline) or in the lower third of the superior vena cava (peripherally inserted central catheter, PIC line) are ideal. These lines have an extremely low incidence
of complications including infections and can remain in situ for up to 12 weeks and one year respectively. Conventional tunnelled central venous catheters are an alternative when long term therapy is required.

Key documents to think about producing locally:

  • Operations Policy.
  • Shared Care Management Plan.
  • Patient Held Record Book.
  • Community Nursing drug, dosing, administration information.
  • Risk assessment for intravenous/ intramuscular drugs.
  • Pharmacy Procedures.
  • Vascular Device information.
  • Medication side effect leaflets.
  • Out of hours advice for patients.
  • Patient/user questionnaires for auditing OPAT service.

From its inception OPAT has been shown to be a safe and effective method of delivering healthcare. These services provide a much needed alternative for the many patients who are occupying a hospital bed solely in order to receive their intravenous antibiotics.

1. Rucher RW, Harrison GM. Outpatient intravenous medications in the management of cystic fibrosis. Pediatrics 1974;54:358-60.
2. Williams DN, Rehm SJ, Tice AD et al. Practice guidelines for community-based parenteral anti-infective therapy. IDSA Practice Gudelines Committee. Clin Infect Dis 1997;25:787-801.
3. Howden BP, Grayson ML. Hospital in the home treatment of infectious diseases. Med J Aust 2002;176:440-5.
4. Fisher DA, et al. Outpatient parenteral antibiotic therapy in Singapore. Int J Antimicrob Agents 2006:28:545-550.
5. Kayley J, et al. Safe intravenous antibiotic therapy
at home: experience of a UK based programme. J Antimicrob Chemother 1996;37:1023-9.
6. Nathwani D. The management of skin and soft tissue infections: Outpatient parenteral antibiotic therapy in the United Kingdom. Chemotherapy 2001;47:Suppl 1,17-23.
7. Seaton R A & Nathwani D. Outpatient and home parenteral antibiotic therapy (OHPAT ); survey of infection specialists’ experience and views. Clin Microbiol and Inf 2000;6:387-400.
8. Seaton R A, et al. Feasibility of an outpatient and home parenteral antibiotic therapy (OHPAT ) programme in Tayside, Scotland. J Infection (1999);39:129-33.
9. Seaton R A, et al. Nurse-led management of uncomplicated cellulites in the community: evaluation of a protocol incorporating intravenous ceftriaxone. J Antimicrob Chemother 2005;55:764-767.
10. Goodfellow AF, Wai AO, Frighetto L et al. Quality of life assessment in an outpatient parenteral antibiotic program. Ann Pharmacother 2002;36:1851-5.
11. Chamberlain TM et al. Cost analysis of a home intravenous antibiotic program. Am J Hosp Pharm 1988;45:2341-5.
12. Eisenberg JM et al. Savings from outpatient antibiotic therapy for osteomyelitis: economic analysis of a therapeutic strategy. JAMA 1986;255:1584-8.
13. Tice AD, Hoaglund PA, Nolet B et al. Cost perspectives for outpatient intravenous antimicrobial therapy. Pharmacotherapy 2002;22:63S-70S.
14. Nathwan D and Conlon C Outpatient and home parenteral antibiotic therapy (OHPAT ) in the UK: a consensus statement by a working party . Clin Microbiol and Inf 1998 6 537-551.
15. Tice A., Rehm S.J. et al Practice Guidelines for outpatient parenteral antimicrobial therapy. Clin Infect Dis 2004;38:1651-72.
16. Gilchrist M, Franklin BD, Patel JP. An outpatient parenteral antibiotic therapy (OPAT ) map to identify risks associated with an OPAT service. J Antimicrob Chemother 2008;62:177-83.
17. Corwin P, Toop L, McGeoch G, et al. Randomised controlled trial of intravenous antibiotic treatment for cellulitis at home compared with hosptial. BMJ 2005;330:129.
18. Matthews P, et al. Outpatient parenteral antimicrobial therapy (OPAT ): is it safe for selected patients to selfadminister at home? A retrospective analysis of a large cohort over 13 years. J Antimicrob Chemother 2007; 60: 356-362.
19. Lamont E, Seaton RA, Macpherson M, et al. Development of teicoplanin dosage guidelines for patients treated within an outpatient parenteral antibiotic therapy (OPAT ) programme. J Antimicrob Chemother 2009; 64:181-187.
20. Novartis Pharmaceuticals UK Limited. Daptomycin Summary of Product Characteristis May 2009.

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