A randomized trial comparing gentamicin/citrate and heparin locks for central venous catheters in maintenance hemodialysis patients.

BACKGROUND: Central venous catheters (CVCs) are used for vascular access in hemodialysis patients who have no alternative access or are awaiting placement or maturation of a permanent access. The major complications of CVCs are catheter-related bloodstream infection and clotting in the catheter lumen. STUDY DESIGN: Parallel-group, randomized, multicenter clinical trial, with patients blinded to study intervention. SETTING & PARTICIPANTS: 16 free-standing dialysis facilities in Northern California belonging to a single provider. 303 adult maintenance hemodialysis patients who were using a tunneled cuffed CVC for vascular access. INTERVENTION: The treatment group received an antibiotic lock containing gentamicin 320 µg/mL in 4% sodium citrate, whereas the control group received the standard catheter lock containing heparin 1,000 U/mL. Both groups received triple-antibiotic ointment on the catheter exit site during dressing changes at each dialysis treatment. OUTCOMES: Catheter-related bloodstream infection and catheter clotting. MEASUREMENTS: Catheter-related bloodstream infection was defined as the occurrence of symptoms consistent with bacteremia together with positive blood culture results in the absence of another obvious source of infection. Catheter clotting was measured as the rate of thrombolytic agent use required to maintain adequate blood flow. A single patient could contribute more than one infection or clotting episode. RESULTS: The rate of catheter-related bloodstream infection was 0.91 episodes/1,000 catheter-days in the control group and 0.28 episodes/1,000 catheter-days in the treatment group (P = 0.003). The time to the first episode of bacteremia was significantly delayed (P = 0.005). The rates of tissue plasminogen activator use were similar in the treatment and control groups: 2.36 versus 3.42 events/1,000 catheter-days, respectively (P = 0.2). LIMITATIONS: The requirement for dialysis facility staff to prepare the treatment intervention prevented a completely blinded study. CONCLUSION: Gentamicin 320 µg/mL in 4% sodium citrate used as a routine catheter lock in CVCs in patients on maintenance hemodialysis therapy markedly decreases the incidence of catheter-related bloodstream infection and is as effective as heparin 1,000 U/mL in preventing catheter clotting.

A multicenter study of the frequency and distribution of GJB2 and GJB6 mutations in a large North American cohort.

PURPOSE: The aim of the study was to determine the actual GJB2 and GJB6 mutation frequencies in North America after several years of generalized testing for autosomal recessive nonsyndromic sensorineural hearing loss to help guide diagnostic testing algorithms, especially in light of molecular diagnostic follow-up to universal newborn hearing screening. METHODS: Mutation types, frequencies, ethnic distributions, and genotype-phenotype correlations for GJB2 and GJB6 were assessed in a very large North American cohort. RESULTS: GJB2 variants were identified in 1796 (24.3%) of the 7401 individuals examined, with 399 (5.4%) homozygous and 429 (5.8%) compound heterozygous. GJB6 deletion testing was performed in 12.0% (888/7401) of all cases. The >300-kb deletion was identified in only nine individuals (1.0%), all of whom were compound heterozygous for mutations in GJB2 and GJB6. Among a total of 139 GJB2 variants identified, 53 (38.1%) were previously unreported, presumably representing novel pathogenic or benign variants. CONCLUSIONS: The frequency and distribution of sequence changes in GJB2 and GJB6 in North America differ from those previously reported, suggesting a considerable role for loci other than GJB2 and GJB6 in the etiology of autosomal recessive nonsyndromic sensorineural hearing loss, with minimal prevalence of the GJB6 deletion.