Straight Versus Coiled Peritoneal Dialysis Catheters: A Randomized Controlled Trial.

RATIONALE & OBJECTIVE: Despite a recent meta-analysis favoring straight catheters, the clinical benefits of straight versus coiled peritoneal dialysis catheters remain uncertain. We conducted a randomized controlled study to compare the complication rates associated with these 2 types of double-cuffed peritoneal dialysis catheters. STUDY DESIGN: Multicenter, open-label, randomized, controlled trial. SETTING & PARTICIPANTS: 308 adult continuous ambulatory peritoneal dialysis patients. INTERVENTION: Participants were randomly assigned to receive either straight or coiled catheters. OUTCOMES: The primary outcome was the incidence of catheter dysfunction requiring surgical intervention. Secondary outcomes included time to catheter dysfunction requiring intervention, catheter migration with dysfunction, infusion pain measured using a visual analogue scale, peritonitis, technique failure, and peritoneal catheter survival. RESULTS: 153 patients were randomly assigned to straight catheters; and 155, to coiled catheters. Among randomly assigned patients who underwent peritoneal dialysis, during a mean follow-up of 21 months, the primary outcome of catheter dysfunction or drainage failure occurred in 9 (5.8%) patients who received a coiled catheter and 1 (0.7%) patient who received a straight catheter. Straight catheters had 5.1% lower risk for catheter dysfunction (95% CI, 1.2%-9.1%; P=0.02). The HR of the primary outcome for coiled versus straight catheters was 8.69 (95% CI, 1.10-68.6; P=0.04). Patients who received a coiled catheter had similar risk for peritonitis but reported higher infusion pain scores than those who received straight catheters. LIMITATIONS: Generalizability to other peritoneal dialysis centers with lower volumes and other races and nationalities. CONCLUSIONS: Use of straight Tenckhoff catheters compared with coiled catheters reduced the rate of catheter dysfunction requiring surgical intervention. FUNDING: Funded by the Chinese University of Hong Kong. TRIAL REGISTRATION: Registered at ClinicalTrials.gov with study number NCT02479295.

Clinical study on low-molecular weight heparin infusion as anticoagulation for nocturnal home haemodialysis.

AIM: This study was conducted to evaluate low-molecular weight heparin (LMWH) as anticoagulation for nocturnal home haemodialysis (NHHD). While its longer half-life may cause drug accumulation in frequent dialysis, the essential need of a supplementary intra-dialytic bolus for the sleeping patients also renders LMWH's use impractical. METHODS: The recruited patients, who were on alternate-day 8 h haemodialysis, were randomized to receive either nadroparin or unfractionated heparin (UFH) for a week. They underwent crossover to receive the alternate anticoagulant in the next week. A nadroparin infusion regimen was adopted to enhance its practicability, which consisted of a loading dose of 35 IU/kg and a continuous infusion of 10 IU/kg per hour for 6 h. RESULTS: A total of 12 NHHD patients were recruited. With nadroparin infusion, the mean anti-Xa levels at the 2nd , 4th , 6th and 8th hours of dialysis were 0.46 ± 0.11, 0.55 ± 0.14, 0.61 ± 0.15 and 0.45 ± 0.15 IU/mL respectively. Comparing to UFH, which offered satisfactory anticoagulation according to the activated partial thromboplastin time, nadroparin-treated dialysis achieved similar thrombus scores and dialyser urea/creatinine clearances at the end of haemodialysis. During the post-dialysis period, one patient demonstrated residual LMWH effect (anti-Xa level 0.09 IU/mL) on the next day, whereas none had detectable anti-Xa activities 2 days afterwards upon next dialysis. CONCLUSIONS: Low-molecular weight heparin infusion is practical and effective as anticoagulation for NHHD. It can be safely used in an alternate-day haemodialysis schedule. A close monitoring for LMWH accumulation is recommended if long dialysis is performed daily.

Correlation between activated partial thromboplastin time and anti-Xa activity in patients who received low-molecular weight heparin as anticoagulation for haemodialysis.

Plasma anti-Xa activity, the recommended test to monitor low-molecular weight heparin (LMWH) therapy, is not readily available in many laboratories. In our clinical trials on the use of LMWH as anticoagulation for haemodialysis, a consistent prolongation of APTT in addition to the elevated anti-Xa activity was observed in the patients after LMWH administration. Hence, the paired anti-Xa activity and APTT data were re-analyzed. The APTT ratio, which was the proportional change in APTT from the baseline value after LMWH administration, was found to have a strong correlation with anti-Xa activity (coefficient of determination, R 2 = 0.72, P < 0.001). In the receiver operating characteristic analysis, the APTT ratio was also found to be an excellent predictor of therapeutic anti-Xa activity ≧0.5 IU/mL (area under curve = 0.93, P < 0.001). The sensitivity was 88% and the specificity was 83.3% when an APTT ratio ≧1.4 was used as the cut point to predict the achievement of therapeutic anti-Xa activity. Our results illustrated that APTT is a potentially useful screening test to assess the degree of anticoagulation achieved by LMWH during haemodialysis, if the testing for plasma anti-Xa activity is not available.

Using herbs medically without knowing their composition: are we playing Russian roulette?

Herbal medicine, a form of complementary and alternative medicine (CAM), is used throughout the world, in both developing and developed countries. The ingredients in herbal medicines are not standardized by any regulatory agency. Variability exists in the ingredients as well as in their concentrations. Plant products may become contaminated with bacteria and fungi during storage. Therefore, harm can occur to the kidney, liver, and blood components after ingestion. We encourage scientific studies to identify the active ingredients in herbs and to standardize their concentrations in all herbal preparations. Rigorous studies need to be performed in order to understand the effect of herbal ingredients on different organ systems as well as these substances' interaction with other medications.

Venous air embolism related to the use of central catheters revisited: with emphasis on dialysis catheters.

Venous air embolism is a dreaded condition particularly relevant to the field of nephrology. In the face of a favourable, air-to-blood pressure gradient and an abnormal communication between the atmosphere and the veins, air entrance into the circulation is common and can bring about venous air embolism. These air emboli can migrate to different areas through three major routes: pulmonary circulation, paradoxical embolism and retrograde ascension to the cerebral venous system. The frequent undesirable outcome of this disease entity, despite timely and aggressive treatment, signifies the importance of understanding the underlying pathophysiological mechanism and of the implementation of various preventive measures. The not-that-uncommon occurrence of venous air embolism, often precipitated by improper patient positioning during cervical catheter procedures, suggests that awareness of this procedure-related complication among health care workers is not universal. This review aims to update the pathophysiology of venous air embolism and to emphasize the importance of observing the necessary precautionary measures during central catheter use in hopes of eliminating this unfortunate but easily avoidable mishap in nephrology practice.

Antibiotic Lock in Tenckhoff Catheter for Biofilm-Associated Peritonitis.

Biofilm bacteria in the Tenckhoff catheter are notoriously difficult to eradicate. They are the potential sources of relapsing or repeat peritonitis among peritoneal dialysis (PD) patients. Inadequate penetration into biofilms by standard intraperitoneal antibiotics, as well as a lack of effective adjunctive treatment, leads to a high rate of Tenckhoff catheter loss as a result of biofilm bacteria. In hemodialysis, on the other hand, catheter-related bloodstream infection caused by biofilm bacteria does not necessarily lead to a loss of catheter. Here, the use of antibiotic lock in conjunction with systemic antibiotics has been shown to be an effective treatment. In this case report, we present 2 cases of biofilm-associated PD peritonitis. The success in salvaging the Tenckhoff catheters by antibiotic lock suggested a potentially similar efficacy in PD patients using this adjunctive treatment, which has not been thoroughly investigated in the literature. Relevant clinical trials are necessary to evaluate whether antibiotic lock is also effective in eradicating biofilm bacteria in the Tenckhoff catheter.

Low-molecular weight heparin infusion as anticoagulation for haemodialysis.

BACKGROUND: Low-molecular weight heparin (LMWH) is commonly used as an anticoagulant for haemodialysis by a single-bolus injection. However, its application in extended haemodialysis has been infrequently studied. In particular, for nocturnal home haemodialysis patients sleeping throughout treatment, the need for additional intradialytic bolus might render the use of LMWH impractical. To overcome this limitation, we changed traditional bolus injections to continuous infusion. We first tested our method among in-centre 4-h haemodialysis patients to establish a feasible and safe infusion regimen before utilizing it in extended dialyses at home. METHODS: Recruited patients were given nadroparin (standardized at 65 IU/kg) as an anticoagulant for haemodialysis. They were first randomized to receive nadroparin either by bolus injection or infusion. Afterwards, the patients underwent crossover to receive the alternate method of LMWH anticoagulation. The degrees of anticoagulation and bleeding complications were compared. RESULTS: Sixteen haemodialysis patients were recruited. After nadroparin administration, anti-Xa levels at the first hour were significantly higher by the bolus than the infusion methods (0.68 ± 0.10 versus 0.49 ± 0.10 IU/mL, P < 0.001) and were similar by the second hour (0.56 ± 0.10 versus 0.55 ± 0.11 IU/mL, P = 0.64). At the sixth hour, anti-Xa levels by the infusion method were significantly higher (0.35 ± 0.13 versus 0.25 ± 0.10 IU/mL, P < 0.001), suggesting the infusion approach required a dosage reduction. There were no bleeding events reported in either method. CONCLUSIONS: LMWH infusion is feasible and safe. The method avoids early excessive anticoagulation caused by bolus injection and reduces the LMWH dose. Future studies should be conducted to evaluate LMWH infusion in extended haemodialysis treatment.