Eight RCTs were included (n=829 patients (range 40 to 291); 882 catheters; 90,191 catheter days). Five RCTs described their method of random sequence generation. Only two gave details of allocation concealment (of which only one used an optimal method). Four were double-blinded, but only two provided detail on blinding procedures.
ALS versus standard heparin lock (eight RCTs)
CRB incidence was significantly lower in the ALS group (RR 0.32, 95% CI: 0.10, 0.42), with heterogeneity of borderline statistical significance (p=0.071). Random-effects analysis also significantly favoured the ALS group (RR 0.20, 95% CI: 0.09, 0.32). Sensitivity analyses did not change the significance of these results.
The four studies evaluating an ALS containing gentamycin showed a significantly greater reduction in the RR of a CRB (RR of 0.08 compared with 0.38, p=0.003). No other variables were found to significantly influence outcomes.
The funnel plot suggested potential publication bias. However, fail-safe N tests suggested that at least 42 studies would be required to negate the statistical significance of the main (fixed-effect) findings.
Adverse events (nine RCTs)
No serious adverse event related to ALS was reported, nor did any RCTs report CRB caused by bacteria resistant to the antibiotic in the lock solution. One study reported that gentamycin was detected in the plasma when a high concentration of gentamycin was used in the ALS. The most commonly reported adverse events were dizziness, paraesthesia and metallic taste.