Vascular Access Infection

The contract between this chapter and the reader.

1. 1. Recognise catheter-related bloodstream infection as the dominant access infection.
2. 2. Diagnose CRBSI with paired blood cultures drawn before antibiotics.
3. 3. Start empiric therapy covering gram-positives (and MRSA) and gram-negatives, dosed for haemodialysis.
4. 4. Decide when the catheter must be removed versus salvaged.
5. 5. Use guidewire exchange and antibiotic-lock therapy appropriately.
6. 6. Set treatment duration by organism and screen S. aureus for metastasis.
7. 7. Manage fistula and graft infection.
8. 8. Recognise the metastatic complications of S. aureus bacteraemia.
9. 9. Build a catheter-infection prevention programme.

A sixty-second reading. Each bullet stands alone.

• Catheters carry by far the highest infection risk of any access, and catheter-related bloodstream infection is the dominant, most dangerous access infection.
• Suspect CRBSI when a catheter patient has fever or rigors — classically during or just after dialysis — with no other source.
• Diagnose with paired blood cultures, from the catheter and the periphery, drawn before antibiotics.
• Gram-positives dominate — coagulase-negative staphylococci and Staph aureus — alongside gram-negatives and occasional Candida.
• Start empiric intravenous antibiotics after cultures: cover gram-positives (a glycopeptide where MRSA is prevalent) and gram-negatives, dosed for haemodialysis.
• Remove the catheter for severe sepsis, S. aureus, Pseudomonas, Candida, tunnel infection, metastatic infection, or persistent bacteraemia beyond 72 hours.
• Attempt salvage with an antibiotic lock only in a stable patient with a low-virulence organism and no tunnel infection or metastasis.
• A guidewire exchange can preserve the site in a stable patient without an exit-site or tunnel infection once bacteraemia is controlled.
• Treat for about two to three weeks; extend to four to six weeks for complicated or metastatic S. aureus.
• Screen S. aureus bacteraemia for endocarditis and other metastatic foci, often with echocardiography.
• Graft infection involves foreign material and often needs surgical excision; fistula infection is rarer and usually treated medically with prolonged antibiotics.
• The single biggest prevention lever is avoiding catheters; then aseptic technique, exit-site care, and antimicrobial locks in high-risk patients.

The medical core. An expert should agree access infection is fully covered here.

Why it matters at the bedside

Every dialysis catheter is a tube that runs from the skin to the heart, and infection follows that path. Catheter-related bloodstream infection is the price of the catheter — common, sometimes lethal, and prone to seeding heart valves and spine. Recognising it early, choosing antibiotics and catheter fate well, and ultimately avoiding catheters altogether is what keeps these patients alive.

The catheter as the source

• Among accesses, the catheter is uniquely infection-prone: organisms reach the bloodstream along the lumen from a contaminated hub, along the outside from the exit and tunnel, or via biofilm on the catheter surface. This is why a fistula or graft is always preferred, and why a febrile catheter patient is assumed infected until proven otherwise.

Recognising and diagnosing CRBSI

• The classic presentation is fever or rigors during or shortly after a dialysis session, with no competing source. Diagnosis rests on paired blood cultures — one from the catheter and one peripheral (or from both lumens) — drawn before antibiotics; a catheter sample turning positive more than about two hours earlier than the peripheral one points to the catheter as the source, and a removed catheter tip can be cultured. The exit site and tunnel may look normal or inflamed.

The organisms

• Gram-positive cocci dominate — coagulase-negative staphylococci (often salvageable) and the more dangerous Staph aureus, including MRSA — with gram-negatives and occasional Candida completing the picture. The organism drives both the antibiotic choice and the fate of the catheter.

Empiric and targeted therapy

• After cultures, start empiric intravenous antibiotics covering gram-positives — a glycopeptide such as vancomycin where MRSA is prevalent and because it suits intermittent haemodialysis dosing — and gram-negatives, adjusted to local epidemiology. Dose for haemodialysis (a loading dose with redosing guided by levels, typically given during or after a session), then narrow to the cultured organism.

The catheter: remove, salvage, or exchange

• The central decision is the catheter's fate. Remove it for severe sepsis or instability, S. aureus, Pseudomonas, or Candida, a tunnel infection, metastatic infection, or bacteraemia persisting beyond about 72 hours on appropriate antibiotics.
• Salvage — keeping the catheter with systemic antibiotics plus an antibiotic lock that sterilises the intraluminal biofilm — is reserved for a stable patient with a low-virulence organism (typically coagulase-negative staphylococci) and no tunnel infection or metastasis. A guidewire exchange, swapping the catheter over a wire once bacteraemia is controlled, preserves the venous site in a stable patient without exit-site or tunnel infection.

Duration and screening for metastasis

• Most CRBSI is treated for about two to three weeks. S. aureus is different: it seeds distant sites — heart valves, spine, joints, bone — so it warrants screening (echocardiography for endocarditis, imaging for focal symptoms) and a longer course of four to six weeks when complicated.

Fistula and graft infection

• A fistula infection is uncommon and is treated like subacute bacterial endocarditis with a prolonged antibiotic course, rarely needing surgery. A graft infection is more serious because the foreign material harbours organisms: localised infection may be partially excised, but extensive or anastomotic graft infection often demands total excision and can threaten the limb or life — a surgical problem.

Metastatic complications

• S. aureus bacteraemia is the one to fear: a new murmur suggests endocarditis, back pain an epidural or vertebral focus, and a hot joint septic arthritis. These change the duration, mandate catheter removal, and are missed at the patient's peril — hence the routine screen.

Prevention

• The dominant lever is to avoid catheters by establishing a fistula or graft. Where a catheter is unavoidable, aseptic hub and connection technique, diligent exit-site care with chlorhexidine, antimicrobial locks in high-risk patients, treatment of S. aureus nasal carriage, and staff-training bundles all reduce the infection rate.

Five fully-built tables.

Table A — Access infection by type

Table B — Diagnosing CRBSI

Table C — The catheter decision

Table D — Organisms and duration

Table E — Prevention bundle

Visualise & Map

Numbered rules. These numbers are the cross-reference handle for the cases and flowcharts.

Clinical Reasoning

Five cases. Each stops you at a decision before it answers it.

Exhaustive. Every threshold and rule in the chapter is here.

Safety & Evidence

Panel A — Red flags

Panel B — NEVER DO

Anti-patterns clinicians fall into. Each becomes a Level 22 distractor.

The grade reflects strength of evidence, not importance.

Patient Decisions

Outcomes as natural frequencies. Figures are representative; the direction of effect is given where precise numbers are uncertain.

Apply & Test

Copy-paste chart notes that map to the real decisions in this chapter.

Template 1 — CRBSI assessment and management note

• Presentation: fever/rigors (on dialysis?) ___; other source excluded: yes/no.
• Cultures: paired (catheter + peripheral) drawn before antibiotics: yes/no; organism ___.
• Empiric therapy: gram-positive agent ___ (MRSA cover?); gram-negative agent ___; HD-dosed.
• Severity / virulence: stable? S. aureus / Pseudomonas / Candida? tunnel infection? metastasis?
• Catheter decision: remove / salvage (lock) / guidewire exchange — rationale ___.

Template 2 — S. aureus / complicated-infection note

• Organism and sensitivities: ___.
• Catheter removed: yes/no; date ___.
• Metastasis screen: echocardiography ___; focal imaging (spine/joint) ___.
• Planned duration: ___ (4–6 weeks if complicated).
• Re-culture / clearance confirmed: ___; new access plan: ___.

Pre-rounds compression. Rules only.

Active recall. At least one card per objective.

Micro-teaching for rounds. Two scenarios, five steps each.

Nine items, each anchored in this chapter. At least one per objective.