Citrate-induced local ionized calcium decrease in pediatric hemodialysis settings: An in-vitro study

BACKGROUND

Citrate is instilled into the dialysis catheter to prevent clotting and to maintain patency between dialysis sessions. A significant amount of citrate leaks from the catheter at the injection time, which decreases the blood ionized calcium concentration (Ca²⁺) due to chelation. We aimed to evaluate the local impact of concentrated (i.e. 30%) citrate spilling on Ca²⁺ at the catheter tip in real-time pediatric conditions.

METHODS

An in-vitro model was constructed, involving an ion-selective electrode (Ca-ISE). A pre-curved catheter and the Ca-ISE were submerged in a glass vessel with the tips positioned adjacent to each other. The vessel was filled with 30 and 80 ml of normal saline with added calcium to simulate normal right atrium size in children and adults, respectively, and normal blood Ca²⁺. The amount of instilled citrate matched the filling volume of the catheter. Measurements were performed with 4% and 30% citrate solutions.

RESULTS

The mean Ca²⁺ measured at the tip of the catheter was 0.457 and 0.058 mmol/l when using 4% and 30% citrate, respectively (p < 0.001). The mean Ca²⁺ recorded in 30 and 80 ml after instilling 30 % citrate was 0.058 and 0.055 mmol/l, respectively (p = 0.878).

CONCLUSIONS

The spilling of 30% citrate caused a strikingly greater decrease of Ca²⁺ at the catheter tip than the standard 4% citrate. The atrial volume did not influence the test results implying similar safety concerns for pediatric and adult patients. The used static experimental setting might have overestimated the spilling effect.

Efficacy of 4% tetrasodium ethylenediaminetetraacetic acid (T-EDTA) catheter lock solution in home parenteral nutrition patients: A quality improvement evaluation

Introduction:

A functioning and reliable central venous access device is fundamental for home parenteral nutrition patients to administer essential nutrition. Complications of central venous access devices including occlusion, microbial colonization, and biofilm formation are problematic and sometimes life-threatening. A novel lock solution, 4% tetrasodium ethylenediaminetetraacetic acid, has properties that may reduce such complications.

Purpose:

The aim of this study was to determine the safety, efficacy, and cost implications of implementing 4% tetrasodium ethylenediaminetetraacetic acid to prevent catheter-related complications in home parenteral nutrition patients.

Methods:

A pre- and post-intervention study was carried over 36 months (12 months pre; 24 months post) by the British Columbia Home Parenteral Nutrition Program in Vancouver, Canada, where 4% tetrasodium ethylenediaminetetraacetic acid was implemented for patients at high risk for central venous access device occlusion and catheter-related infection. Patients were included in the study if they had previous central venous access device complications. The outcomes evaluated were central line-associated bloodstream infection, catheter occlusion requiring thrombolytic treatment, and catheter replacements.

Results:

In total, 22 out of 105 patients met the inclusion criteria. Two patients were excluded from analyses due to non-adherence and concomitant use of other lock solutions. Post intervention, 20 home parenteral nutrition patients experienced significant reduction in the central line-associated bloodstream infection rate (pre = 1.918/1000 catheter days; post = 0.563/1000 catheter days; p = 0.04) There were no occlusion events reported post intervention.

Conclusion:

For home parenteral nutrition patients, 4% tetrasodium ethylenediaminetetraacetic acid lock solution effectively reduces the risk of central venous access device complications including occlusions and catheter-related infections.

Prevention of hemodialysis catheter infections: Ointments, dressings, locks, and catheter hub devices

Tunneled central venous catheters used for the provision of hemodialysis are associated with excess morbidity and mortality. Catheter related exit site and blood stream infections are major risks of their use. Although catheter-avoidance is the best strategy to reduce infections and mortality in the hemodialysis population, the use of catheters remains unacceptably high. In this review, the existing clinical practice guidelines for the prevention of hemodialysis catheter associated infections are outlined, and a comprehensive evidenced-based summary of interventions is provided. This includes details about the use of topical antimicrobial ointments and dressings, intranasal ointment application, prophylactic use of antibiotic and non-antibiotic catheter lock solutions, and catheter hub devices for the prevention of catheter blood stream infections.

Cluster-Randomized Trial of Devices to Prevent Catheter-Related Bloodstream Infection

Central venous catheters (CVCs) contribute disproportionately to bloodstream infection (BSI) and, by extension, to infection-related hospitalization, mortality, and health care costs in patients undergoing dialysis. Recent product advancements may reduce BSIs, but a sufficiently powered comparative-effectiveness study is needed to facilitate evidence-based patient care decisions. In a 13-month, prospective, cluster-randomized, open-label trial, we compared BSI rates in facilities using ClearGuard HD antimicrobial barrier caps (ClearGuard group) with those in facilities using Tego hemodialysis connectors plus Curos disinfecting caps (Tego+Curos group). Forty DaVita dialysis facilities in the United States were pair-matched by BSI rate, number of patients using CVCs, and geographic location, and then cluster randomized 1:1. We enrolled all adult patients undergoing dialysis with CVCs at these facilities, except those allergic to heparin or chlorhexidine. Overall, 1671 patients participated in the study, accruing >183,000 CVC-days. The study outcome was positive blood culture (PBC) rate as an indicator of BSI rate. We calculated results at the cluster level and adjusted for the facility cluster effect. During a 3-month run-in period immediately before study interventions, the groups had similar BSI rates (P=0.8). During the 13-month intervention period that immediately followed, the ClearGuard group had a BSI rate significantly lower than that of the Tego+Curos group (0.28 versus 0.75 PBCs per 1000 CVC-days, respectively; P=0.001). No device-related adverse events were reported. In conclusion, compared with Tego connectors plus Curos caps, ClearGuard HD antimicrobial barrier caps significantly lowered the rate of catheter-related BSIs in patients undergoing hemodialysis using CVCs, representing an important advancement in hemodialysis patient care.

Quasi-experimental study of sodium citrate locks and the risk of acute hemodialysis catheter infection among critically ill patients

Critically ill patients who require renal replacement therapy (RRT) are vulnerable to catheter-related bloodstream infections (CRBSI). This study compared the risks of dialysis catheter infection according to the choice of locking solution in the intensive care unit (ICU). A prospective quasi-experimental study with marginal structural models (MSM) and 2:1 greedy propensity-score matching (PSM) was conducted at nine university-affiliated hospitals and three general hospitals. A total of 596 critically ill patients received either saline solution or heparin lock solution (the standard of care [SOC]) from 2004 to 2007 in the Cathedia cohort (n = 464 for MSM; n = 124 for PSM) or 46.7% citrate lock from 2011 to 2012 in the citrate (CLock) cohort (n = 132 for MSM; n = 62 for PSM) to perform RRT using intermittent hemodialysis. Catheter-tip colonization and CRBSI were analyzed. The mean duration (standard deviation [SD]) of catheterization was 7.1 days (6.1) in the SOC group and 7.0 days (5.9) in the CLock group (P = 0.84). The risk of dialysis catheter-tip colonization was lower in the CLock group (20.5 versus 38.7 per 1,000 catheter-days in the SOC group; hazard ratio [HR] from MSM, 0.73; 95% confidence interval [CI], 0.57 to 0.93; P < 0.02). Consistent findings were found from PSM (HR, 0.46; 95% CI, 0.22 to 0.95; P < 0.04). The risk of CRBSI was nonsignificantly different in the CLock group (1.1 versus 1.8 per 1,000 catheter-days in the SOC group; HR from MSM, 0.48; 95% CI, 0.12 to 1.87; P = 0.29). By reducing the risk of catheter-tip colonization, citrate lock has the potential to improve hemodialysis safety in the ICU. Additional studies are warranted before the routine use of citrate locks can be recommended in the ICU.