Successful use of single-lumen, urokinase immobilized femoral catheters as a temporary access for haemodialysis

“Long-Term” Catheters for Haemodialysis: Malfunction and Management

The purpose of this study is to demonstrate the incidence of dysfunction due to thrombosis of the central venous catheters (tunnelized and siliconic) for haemodialysis.

We have also correlated the rate of the thrombotic events to the site of positioning and to the different protocols used in order to prevent these complications.

Femorals are more affected by thrombosis, partial or total, than jugular catheters.

The mean request of the urokinase-boluses is low: only 10% of the dialytic sessions examined (1200) requires these interventions.

A significant reduction is obtained if to the patients are administered ASA. No influence seems to result from the use of the anticoagulants.

Our study confirms in our population the advantages of central venous catheters in chronic haemodialysis, the ease of management and the absence of serious complications during the observation period (6 months).

Central Venous Catheter and the Hemodialysis Patient: A Difficult Symbiosis

In the last ten years, tunneled central venous catheters (pCVCs) have been increasingly utilized in chronic hemodialysis patients, sometimes in the place of fistulas. They have gained popularity for their unquestioned advantages, such as the possibility for immediate use. However, several problems have emerged following their diffusion. In this paper we review the main complications of pCVCs. Complications connected with insertion are generally due to an inaccurate approach to the vein. Ultrasonographic guidance has partially solved this problem and EC-ECG (endocavitary ECG) allows an accurate positioning of the tip. Infections, venous and/or pCVCs) thrombosis and dysfunctions are the most important catheter-related complications. Infections may occur with and without symptoms of systemic illness. Early diagnosis and appropriate antibiotic treatment are essential for saving the catheter. The pathogenesis of infections and strategies for prevention are discussed. Thrombosis and stenosis are well known complications of subclavian and jugular catheterization. In uremic patients, for temporary use, we suggest using the femoral position. Protocols for application of thrombolytic agents in pCVCs are considered. Dysfunction, defined as the failure to maintain a blood flow of at least 250 ml/min, remains the Achilles’ heel of the system. Adequate look therapy and tip position are only two basic aspects. In conclusion, a pessimistic outlook on the matter could lead us to consider that the advantages of catheter use are far outweighed by the disadvantages. However, we cannot avoid using central venous catheters in our dialysis units and a great challenge awaits both physicians and manufactures in the coming years.

Natural saline-flush is sufficient to maintain patency of immobilized-urokinase double-lumen catheter used to provide temporary blood access for hemodialysis

BACKGROUND

Thrombotic occlusion is a frequent complication of central venous catheters used to provide temporary blood access on hemodialysis therapy. Heparin-lock is conventionally used to maintain patency of the catheter, but the necessity of heparin-lock has not been determined yet.

METHODS

After the immobilized-urokinase double-lumen central venous catheter was inserted into 48 Japanese hemodialysis patients, 22 patients randomized to the heparin group received a 20-ml saline-flush, followed by 2 ml of 1,000 U/ml heparin-lock, and 26 patients randomized to the saline group received only the 20-ml saline-flush once a day for each lumen.

RESULTS

Thrombotic occlusion was observed in only 1 out of 22 patients in the heparin group and 1 out of 26 patients in the saline group. No significant difference of the catheter survival was observed between the two groups (p = 0.8599).

CONCLUSIONS

Natural saline-flush is sufficient for maintaining the patency of an immobilized-urokinase double-lumen central venous catheter.

Risk factors for thromboembolism in teens: when should I test?

The discoveries of the factor V Leiden mutation and the prothrombin gene variant 20210 in the last decade have markedly contributed to the understanding of the molecular pathophysiology of inherited risk factors for thrombophilia. Population studies in the adult literature have shown that although the overall prevalence of these defects is low, affected individuals are at increased risk of thrombosis particularly if acquired risk factors for thrombosis are also present. The use of combined hormonal oral contraceptive pills is a well-known acquired risk factor, and recent studies have shown significant increased risk of thrombosis for women who carry the factor V Leiden mutation and use oral contraceptive pills. Despite this significant increased risk, mass screening of asymptomatic women for factor V Leiden prior to prescribing oral contraceptive pills is not a cost-effective use of health care dollars and could result in unnecessarily preventing many women from the contraceptive and noncontraceptive benefits of this medication. Instead, clinicians can use thoughtful screening questions to identify potentially high-risk patients for thrombophilia and consider testing for inherited risk factors on a case-specific basis.

Risk of heparin lock-related bleeding when using indwelling venous catheter in haemodialysis

BACKGROUND

The indwelling venous catheter such as Dual-Cath or Twin-Cath is widely used in haemodialysis. Although the manufacturer recommends filling the catheter lumen with heparin after the dialysis session to prevent clotting, little is known about the systemic effects of such a procedure.

METHODS

Twenty haemodialysis patients with Dual-Cath were studied. Dialysis anticoagulation was achieved by injecting a bolus of dalteparin. The patient/control ratio of activated partial thromboplastin time (aPTT) was determined at the end of the session immediately before and 10 min after locking with 2 ml of undiluted heparin (10,000 U/catheter). We also determined the catheter volume for each patient and measured aPTT immediately before and 10 min after heparin locking with this patient-specific volume. Catheter patency was followed over a 2-week period.

RESULTS

The aPTT values determined at the end of two consecutive dialysis sessions were nearly normal, respectively 1.29 (+/-0.17) and 1.33 (+/-0.22), whereas all patients had uncoagulable blood (aPTT >3.75) 10 min after locking with 2 ml of heparin. When catheter volumes were individually calculated, they were found to be substantially lower than 2.0 ml (1.21+/-0.12 for the arterial branch and 1.27+/-0.13 for the venous branch). aPTT was only 2.42+/-0.73 10 min after locking with the estimated volumes except in one patient (aPTT >3.75). No catheter clotting was observed despite these smaller locking volumes.

CONCLUSIONS

A risk of inducing serious bleeding does indeed exist with Dual-Cath heparin locking, especially in postoperative patients. This risk can be reduced by measuring catheter length at the time of placement in order to ensure an appropriate lock volume. Sodium citrate, polygeline, or urokinase are possible alternatives to heparin.