Normal saline (0.9% sodium chloride) versus heparin intermittent flushing for the prevention of occlusion in long-term central venous catheters in infants and children

The effect of different flushing and locking techniques on catheter occlusion rates in central venous catheters: protocol for a multicentre, randomized controlled, parallel-group, open-label, superiority clinical trial

BACKGROUND

Maintaining venous access is of great clinical importance. Running a slow continuous infusion to keep the vein open (KVO) is often used in peripheral intravenous catheters (PIVCs). Previous studies have compared the effects of intermittent flushing and continuous infusion via peripherally inserted central catheters (PICCs). In this study, we applied KVO to central venous catheters (CVCs) and compared the occlusion rate of this technique with that of the intermittent flushing technique.

METHOD

This is a randomized controlled trial of 14 hospitals in China. A total of 250 patients will be recruited in this study, and they will be randomized at a 1:1 ratio. After study inclusion, patients who will undergo CVC insertion will receive intermittent flushing with prefilled saline syringes (control group) or KVO infusion with elastic pumps (test group). All the catheters will be checked for patency by scoping Catheter Injection and Aspiration (CINAS) Classification on Days 3 and 7. The primary outcome is the rate of catheter occlusion in 7 days. Patients will be followed up until 9 days after CVC insertion, catheter occlusion, or catheter removal. The secondary outcomes are the rate of catheter occlusion in 3 days, nurse satisfaction, cost-effectiveness, adverse event rate, catheter-related bloodstream infection rate, catheter-related thrombosis rate, extravasation rate, phlebitis rate, and catheter migration.

DISCUSSION

We expect that the trial will generate findings that can provide an evidence-based basis for the improvement and optimization of clinical catheter flushing techniques.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR2200064007. Registered on 23 September 2022. https://www.chictr.org.cn/showproj.html?proj=177311 .

The effect of taurolidine on the time-to-positivity of blood cultures

Background

Taurolidine containing lock solutions (TL) are a promising method for the prevention of central line associated bloodstream infections. Per accident, the TL may not always be aspirated from the central venous catheter (CVC) before blood cultures are obtained. The TL could, unintentionally, end up in a blood culture vial, possibly altering the results. The aim of this study was to investigate the effect of the TLs on the detection of microbial growth in blood culture vials.

Methods

Different lock solutions (taurolidine-citrate-heparin (TCHL), taurolidine, heparin, citrate or NaCl) were added to BD BACTECTM blood culture vials (Plus Aerobic/F, Lytic/10 Anaerobic/F or Peds Plus/F) before spiking with Staphylococcus aureus (ATCC 29213 or a clinical strain) or Escherichia coli (ATCC 25922 or a clinical strain) in the presence and absence of blood. Subsequently, blood culture vials were incubated in the BD BACTEC FX instrument with Time-to-positivity (TTP) as primary outcome. In addition, the effect of the TCHL on a variety of other micro-organisms was tested.

Discussion

In the presence of taurolidine, the TTP was considerably delayed or vials even remained negative as compared to vials containing heparin, citrate or NaCl. This effect was dose-dependent. The delayed TTP was much less pronounced in the presence of blood, but still notable.

Conclusion

This study stresses the clinical importance of discarding TLs from the CVC before obtaining a blood culture.

Guideline for Vascular Access Port Use and Maintenance in Large Animals for Biomedical Research

Purpose Vascular Access Ports (VAPs) consist of an indwelling catheter connected to an implanted port that provides direct access for sample collection or infusion. The use of VAPs in biomedical research reduces trauma on vessels from repeated venipuncture, decreases secondary infections, promotes social housing and animal welfare, and increases the accuracy and efficiency of study procedures. In addition to enabling comprehensive data collection, VAPs increase satisfaction, and well-being by minimizing interference with daily routines and fostering cooperation. The responsible use of VAPs includes approval by the institutional animal care and use committee (IACUC), verification of the surgeon′s skill and experience, and confirmation that research staff are trained on the proper maintenance and access techniques. This document aims to provide surgeons, researchers and research staff, veterinary staff, and IACUCs with guidelines for implanting, maintaining, accessing, and troubleshooting vascular access ports in large animal species. (Rabbit, Canine, Feline, Nonhuman Primate, Porcine).

Heparin versus 0.9% sodium chloride locking for prevention of occlusion in central venous catheters in adults

BACKGROUND

Intermittent locking of central venous catheters (CVCs) is undertaken to help maintain their patency and performance. There are systematic variations in care: some practitioners use heparin (at different concentrations), whilst others use 0.9% sodium chloride (normal saline). This review looks at the effectiveness and safety of intermittent locking with heparin compared to normal saline, to see if the evidence establishes whether one is better than the other. This is an update of an earlier Cochrane Review.

OBJECTIVES

To evaluate the benefits and harms of intermittent locking of CVCs with heparin versus normal saline in adults to prevent occlusion.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 20 October 2021.

SELECTION CRITERIA

We included randomised controlled trials in adults ≥ 18 years of age with a CVC that compared intermittent locking with heparin at any concentration versus normal saline. We excluded studies on infants and children from this review.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were occlusion of CVCs and duration of catheter patency. Our secondary outcomes were CVC-related bloodstream infections and CVC-related colonisation, mortality, haemorrhage, heparin-induced thrombocytopaenia, CVC-related thrombosis, number of additional CVC insertions, abnormality of coagulation profile and allergic reactions to heparin. We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We identified one new RCT with 30 participants for this update. We included a total of 12 RCTs with 2422 participants. Data for meta-analysis were available from all RCTs. We noted differences in methods used by the included studies and variation in heparin concentrations (10 to 5000 IU/mL), time to follow-up (1 to 251.8 days), and the unit of analysis used (participant, catheter, line access). Five studies included ICU (intensive care unit) patients, two studies included oncology patients, and the remaining studies included miscellaneous patients (chronic kidney disease, haemodialysis, home care patients, etc.). Primary outcomes Overall, combined results may show fewer occlusions with heparin compared to normal saline but this is uncertain (risk ratio (RR) 0.70, 95% confidence interval (CI) 0.51 to 0.95; 10 studies; 1672 participants; low-certainty evidence). We pooled studies that used participant or catheter as the unit of analysis. We carried out subgroup analysis by unit of analysis. No clear differences were detected after testing for subgroup differences (P = 0.23). We found no clear evidence of a difference in the duration of catheter patency with heparin compared to normal saline (mean difference (MD) 0.44 days, 95% CI -0.10 to 0.99; 6 studies; 1788 participants; low-certainty evidence). Secondary outcomes We found no clear evidence of a difference in the following outcomes: CVC-related bloodstream infections (RR 0.66, 95% CI 0.08 to 5.80; 3 studies; 1127 participants; very low-certainty evidence); mortality (RR 0.76, 95% CI 0.44 to 1.31; 3 studies; 1100 participants; very low-certainty evidence); haemorrhage (RR 1.54, 95% CI 0.41 to 5.74; 3 studies; 1197 participants; very low-certainty evidence); or heparin-induced thrombocytopaenia (RR 0.21, 95% CI 0.01 to 4.27; 3 studies; 443 participants; very low-certainty evidence). The main reasons for downgrading the certainty of evidence for the primary and secondary outcomes were unclear allocation concealment, suspicion of publication bias, imprecision and inconsistency.

AUTHORS' CONCLUSIONS

Given the low-certainty evidence, we are uncertain whether intermittent locking with heparin results in fewer central venous catheter occlusions than intermittent locking with normal saline in adults. Low-certainty evidence suggests that heparin may have little or no effect on catheter patency duration. Although we found no evidence of differences in safety (CVC-related bloodstream infections, mortality, or haemorrhage), the combined studies were not powered to detect rare adverse events such as heparin-induced thrombocytopaenia. Further research conducted over longer periods would reduce the current uncertainties.

Heparin Versus Normal Saline: Flushing Effectiveness in Managing Central Venous Catheters in Pediatric Patients With Cancer

BACKGROUND

There is insufficient evidence of the effects of intermittent flushing with normal saline versus heparin to prevent occlusion or increased alteplase use in pediatric patients with central venous catheters.

OBJECTIVES

The primary objective was to evaluate the effectiveness of a new standard flushing practice in the management of central venous access devices in pediatric patients with cancer. A secondary objective was to assess the cost of heparin flushing supplies to patients and financial impact.

METHODS

New flushing guidelines included tunneled lines flushed with saline in the push-pause method twice daily in the inpatient setting. The outpatient setting required saline lock while receiving care and heparin lock on discharge. Alteplase usage was monitored for five months in all pediatric patients with cancer who had tunneled central lines.

FINDINGS

There was no statistically significant difference in alteplase usage rate pre- to postimplementation. A formal flushing guideline was recommended using saline and lower heparin concentrations for tunneled catheters.

Routine Catheter Lock Solutions in Pediatric Cancer Care: A Pilot Randomized Controlled Trial of Heparin vs Saline

BACKGROUND

Central venous access devices (CVADs) are integral to cancer care provision. Despite the high prevalence of CVAD complications in children with cancer, preventative strategies are understudied.

OBJECTIVE

The aim of this study was to assess study feasibility, occlusive events, thrombolytic use, adverse events, and direct costs of catheter lock solutions.

METHODS

A single-center, parallel-group, pilot randomized controlled trial was undertaken at a tertiary-referral pediatric hospital in Australia. Children 18 years or younger with an oncological or malignant hematological condition and a CVAD were eligible. Participants were 1:1 randomized to (1) normal or (2) heparinized (10-100 U/mL; CVAD-type dependent) saline lock solutions.

RESULTS

Of 217 children assessed for eligibility, 61 were recruited and randomized to normal (n = 30; 3850 CVAD days) or heparinized (n = 31; 4036 CVAD days) saline. Eligibility (52%) and recruitment (54%) feasibility targets were not met. Protocol adherence was high (95% assessments), with no attrition. Parent/clinician satisfaction of interventions was high (median, 10/10 clinicians/parents). Complete CVAD occlusion occurred in heparin only (n = 2, 6.7% CVADs; incidence rate [IR], 0.49/1000 CVAD days [0.06-1.78]). Central venous access device partial occlusion was detected in 23.3% of CVADs in heparin (n = 7; IR, 2.73/1000 CVAD days [1.36-4.87]) and 13.8% of CVADs in normal saline (n = 4; IR, 2.59/1000 CVAD days [1.24-4.77]). Thrombolytic agents were used in 16.7% heparin (5 CVADs) and 3.5% normal saline (1 CVAD). Adverse events did not differ between groups.

CONCLUSION

Multisite randomized controlled trials examining CVAD locks are safe, but strategies and resources to increase recruitment and eligibility are required.

IMPLICATIONS FOR PRACTICE

Both routine CVAD lock solutions seem safe but may not prevent all forms of CVAD-associated harm.

Low molecular weight heparin for prevention of central venous catheter-related thrombosis in children

BACKGROUND

The prevalence of children diagnosed with thrombotic events has been increasing in the last decades. The most common thrombosis risk factor in neonates, infants and children is the placement of a central venous catheter (CVC). It is unknown if anticoagulation prophylaxis with low molecular weight heparin (LMWH) decreases CVC-related thrombosis in children. This is an update of the Cochrane Review published in 2014.

OBJECTIVES

To determine the effect of LMWH prophylaxis on the incidence of CVC-related thrombosis and major and minor bleeding complications in children. Further objectives were to determine the effect of LMWH on occlusion of CVCs, number of days of CVC patency, episodes of catheter-related bloodstream infection (CRBSI), other side effects of LMWH (allergic reactions, abnormal coagulation profile, heparin-induced thrombocytopaenia and osteoporosis) and mortality during therapy.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 7 May 2019. We undertook reference checking of identified trials to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-randomised trials comparing LMWH to no prophylaxis (placebo or no treatment), or low-dose unfractionated heparin (UFH) either as continuous infusion or flushes (low-dose UFH aims to ensure the patency of the central line but has no systemic anticoagulation activity), given to prevent CVC-related thrombotic events in children. We selected studies conducted in children aged 0 to 18 years.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified eligible studies, which were assessed for study methodology including bias, and extracted unadjusted data where available. In the data analysis step, all outcomes were analysed as binary or dichotomous outcomes. The effects of interventions were summarised with risk ratios (RR) and their respective 95% confidence intervals (CI). We assessed the certainty of evidence for each outcome using the GRADE approach.

MAIN RESULTS

One additional study was included for this update bringing the total to two included studies (with 1135 participants). Both studies were open-label RCTs comparing LMWH with low-dose UFH to prevent CVC-related thrombosis in children. We identified no studies comparing LMWH with placebo or no treatment. Meta-analysis found insufficient evidence of an effect of LMWH prophylaxis in reducing the incidence of CVC-related thrombosis in children with CVC, compared to low-dose UFH (RR 0.68, 95% CI 0.27 to 1.75; 2 studies; 787 participants; low-certainty evidence). One study (158 participants) reported symptomatic and asymptomatic CVC-related thrombosis separately and detected no evidence of a difference between LMWH and low-dose UFH (RR 1.03, 95% CI 0.21 to 4.93; low-certainty evidence; RR 1.17, 95% CI 0.45 to 3.08; low-certainty evidence; for symptomatic and asymptomatic participants respectively). There was insufficient evidence to determine whether LMWH impacts the risk of major bleeding (RR 0.27, 95% CI 0.05 to 1.67; 2 studies; 813 participants; low-certainty evidence); or minor bleeding. One study reported minor bleeding in 53.3% of participants in the LMWH arm and in 44.7% of participants in the low-dose UFH arm (RR 1.20, 95% CI 0.91 to 1.58; 1 study; 158 participants; very low-certainty evidence), and the other study reported no minor bleeding in either group (RR: not estimable). Mortality during the study period was reported in one study, where two deaths occurred during the study period. Both were unrelated to thrombotic events and occurred in the low-dose UFH arm. The second study did not report mortality during therapy per arm but showed similar 5-year overall survival (low-certainty evidence). No additional adverse effects were reported. Other pre-specified outcomes (including CVC occlusion, patency and CRBSI) were not reported.

AUTHORS' CONCLUSIONS

Pooling data from two RCTs did not provide evidence to support the use of prophylactic LWMH for preventing CVC-related thrombosis in children (low-certainty evidence). Evidence was also insufficient to confirm or exclude a difference in the incidence of major and minor bleeding complications in the LMWH prophylaxis group compared to low-dose UFH (low and very low certainty respectively). No evidence of a clear difference in overall mortality was seen. Studies did not report on the outcomes catheter occlusion, days of catheter patency, episodes of CRBSI and other side effects of LMWH (allergic reactions, abnormal coagulation profile, heparin-induced thrombocytopaenia and osteoporosis). The certainty of the evidence was downgraded due to risk of bias of the included studies, imprecision and inconsistency, preventing conclusions in regards to the efficacy of LMWH prophylaxis to prevent CVC-related thrombosis in children.