Protocol for Maintaining Central Line Viability with Vancomycin Until Port Placement
Use antibiotic lock therapy (ALT) with vancomycin at a concentration of 5 mg/mL mixed with heparin (2500-5000 IU/mL) or normal saline, instilled into the catheter lumen with a dwell time of at least 12 hours (ideally 24-48 hours), changed every 48 hours, combined with systemic antibiotic therapy if infection is present. 1
Preparation of Vancomycin Lock Solution
Prepare vancomycin lock solution at 5 mg/mL concentration rather than lower concentrations (2.0-2.5 mg/mL), as this maintains concentrations >1000 times the MIC90 of staphylococci throughout the dwell time and is more efficacious at eradicating biofilm-embedded bacteria 1
Mix vancomycin with either heparin (2500-5000 IU/mL) or normal saline in sufficient volume to fill the catheter lumen (typically 2-5 mL) 1
Note that vancomycin at 5 mg/mL remains stable and will not precipitate when mixed with heparin at these concentrations, though precipitation occurs at 10 mg/mL vancomycin with 10,000 IU/mL heparin 1
The solution remains stable at 25°C and 37°C for several days 1
Administration Protocol
Instill the vancomycin lock solution into the catheter lumen and leave it dwelling for 12-48 hours (minimum 8 hours per day, ideally ≥12 hours) 1
Change the antibiotic lock solution at least every 48 hours to maintain therapeutic concentrations, as vancomycin concentrations decrease rapidly over time, especially in ambulatory patients 1
Use true "lock" technique (instilling solution for a defined dwell period) rather than simply flushing through the device, as this confers significantly greater benefit with a risk ratio of 0.34 for preventing bloodstream infection 2
When the catheter needs to be accessed, aspirate and discard the lock solution before use, then flush with normal saline 1
Concurrent Systemic Therapy Considerations
Antibiotic lock therapy does not replace systemic antimicrobial therapy if active infection is present 1
If catheter-related bloodstream infection (CRBSI) is suspected, initiate empirical systemic vancomycin therapy before culture results are available 1
For systemic vancomycin dosing, target trough concentrations of 15-20 mg/L for serious infections, using doses of 15-20 mg/kg every 8-12 hours for patients with normal renal function 1
Systemic vancomycin does not adequately penetrate into the catheter lumen (achieving only 0.2 mcg/mL intraluminally despite serum levels of 17 mcg/mL), making antibiotic lock essential for catheter salvage 3
Once blood cultures are negative and sepsis has resolved, systemic therapy can be transitioned to oral antibiotics (clindamycin, doxycycline, fluoroquinolone, or linezolid) while continuing the antibiotic lock 1
Duration of Therapy
Continue antibiotic lock therapy for 7-14 days if attempting catheter salvage with documented infection 1
Most studies have used a 2-week duration, though duration has varied from 3-30 days in different trials 1
For prophylactic use in high-risk patients without active infection, continue until the permanent port is placed 2, 4
Monitoring and Safety
Monitor for signs of catheter occlusion or thrombosis, as antibiotic lock solutions can affect catheter patency 5
Flush the catheter with normal saline after each use and before reinstalling the lock solution 1
Monitor renal function in patients receiving systemic vancomycin, especially those with baseline renal impairment or receiving other nephrotoxic agents 1, 6
Check vancomycin trough levels before the fourth dose if using systemic therapy, targeting 15-20 mg/L for serious infections 1
Perform surveillance blood cultures to document clearance of bacteremia if infection was present 1
Critical Contraindications and Limitations
Do not attempt catheter salvage with antibiotic lock if any of the following are present: severe sepsis, tunnel infection, port abscess, suppurative thrombophlebitis, endocarditis, or persistent bacteremia after 48-72 hours of appropriate therapy 1
Remove the catheter immediately if infection is due to S. aureus, fungi (especially Candida), or mycobacteria, as antibiotic lock therapy has high failure rates with these organisms (50% failure with S. aureus, even higher with Candida) 1
Antibiotic lock therapy is ineffective for extraluminal infections, which are more common in catheters in place <2 weeks 1
Do not use antibiotic lock if there are signs of exit site infection or tunnel infection 1
Drug Compatibility Considerations
Never mix vancomycin with β-lactam antibiotics (including piperacillin/tazobactam, ceftazidime, imipenem, cefepime, flucloxacillin, or temocillin) as major incompatibilities and precipitation occur 7
Vancomycin is also incompatible with moxifloxacin, propofol, valproic acid, phenytoin, theophylline, methylprednisolone, and furosemide 7
Adequately flush intravenous lines between administration of vancomycin and incompatible antibiotics 6
Compatible agents include ciprofloxacin, aminoglycosides, macrolides, ketamine, sufentanil, midazolam, morphine, and vasopressors 7
Expected Outcomes
Catheter salvage without relapse occurs in approximately 75-77% of cases when antibiotic lock is used with systemic therapy, compared to 58% with systemic therapy alone 1
In high-risk neonates, vancomycin lock reduced CRBSI from 30% to 5% (2.3 vs 17.8 per 1000 catheter days) 4
Meta-analysis shows vancomycin-heparin lock reduces risk of device-associated bloodstream infection with a risk ratio of 0.49 overall 2
Alternative Considerations
If vancomycin resistance is a concern, 70% ethanol lock has shown high success rates in pediatric studies, though this is still being evaluated 1
For methicillin-susceptible staphylococci, cefazolin 5 mg/mL is the preferred lock agent 1
In units with low prevalence of methicillin-resistant staphylococci, cefazolin may be used instead of vancomycin for empirical therapy 1