Dialysis catheters in the ICU: selection, insertion and maintenance

PURPOSE OF REVIEW

Choosing the best catheter for renal replacement therapy (RRT) is not an easy task. Beyond catheter length, many of its properties can influence effectiveness of the RRT session. Maintenance between sessions, particularly the locking solution, also impacts catheter lifespan and infection rates.

RECENT FINDINGS

Many innovations in dialysis catheters have been proposed by the industry over the past decade, including the material used, the shape of the lumens and the position of the inflow and outflow holes. Impregnated catheters have also been developed to prevent catheter-related infections. Many locking solutions are available, either for maintaining catheter patency or for preventing infections.

SUMMARY

Although studies conducted in the specific context of the ICU are still scarce, some conclusions can be drawn. Catheter length must be adapted to the insertion site to reach an area of high blood flow. Kidney-shape lumens appear to be less thrombogenic and seem to prevent catheter dysfunction. Catheter tip and lumen holes also affect catheter function. For catheter locking, 4% citrate appears nowadays as one of the best options, but taurolidine-based solutions are also interesting.

Haemodialysis catheters in the intensive care unit

Ten to 15% of critically ill patients need renal replacement therapy (RRT) for severe acute kidney injury. The dialysis catheter is critical for RRT quality and efficiency. Catheters have several properties that must be optimized to promote RRT success. The distal tip has to be located in a high blood flow location, which means central venous territory. Therefore, catheters are mostly inserted into the right internal jugular vein or in femoral veins. External diameter should vary from 12 to 16 Fr in order to ensure adequate blood flow inside the catheter. Lumen shapes are theoretically designed to limit thrombotic risk with low turbulences and frictional forces against the internal wall. With low aspiration pressure, distal tip shape has to deliver sufficient blood flow, while limiting recirculation rate. Catheter material should be biocompatible. Despite in vitro data, no strong evidence supports the use of coated catheters in the ICU in order to reduce infectious risk. Antibiotic "lock" solutions are not routinely recommended. Ultrasound guidance for catheterization significantly decreases mechanical complications. Clinicians should select the optimal catheter according to patient body habitus, catheter intrinsic properties and RRT modality to be used.

A comparison of the Niagara and Medcomp catheters for continuous renal replacement therapy

PURPOSE

The choice of vascular access catheter may affect filter life during continuous renal replacement therapy (CRRT). In particular, differences in catheter design might affect the incidence of circuit clotting related to catheter malfunction.

DESIGN AND SETTING

Sequential controlled study in a tertiary, adult intensive care unit (ICU).

AIM

To compare circuit life when CRRT was performed with a Niagara catheter or a Medcomp catheter.

PATIENTS AND MEASUREMENTS

We studied 46 patients with acute kidney injury requiring CRRT, all delivered with catheters in the femoral position. We obtained information on age, gender, disease severity score [acute physiology and chronic health evaluation (APACHE II) and APACHE III], filter life, heparin dose per hour, daily systemic hemoglobin concentration, platelet count, international normalized ratio (INR), and activated partial thromboplastin time (APTT) during CRRT.

RESULTS

We studied 254 circuits in 46 patients. Of these, 26 patients (140 circuits) used the Niagara catheter and 20 patients (114 circuits) used the Medcomp catheter. Median circuit life in the two groups were 11 h and 7.3 h, respectively (p < 0.01). Patients using Medcomp catheters had a lower platelet count (p = 0.04) and a lower hemoglobin concentration (p = 0.01), but INR (p = 0.16), APTT (p = 0.46), anticoagulant treatment (p = 0.89), and heparin dose per hour (p = 0.24) were similar. After correcting for confounding variables by multivariable linear regression analysis, it was found that the choice of catheter is not an independent predictor of circuit life. On Kaplan-Meier survival analysis, circuit life was not significantly different between the two catheters (p = 0.87).

CONCLUSION

The choice of either the Niagara or Medcomp catheter does not appear to be a significant independent determinant of circuit life during CRRT.

A comparison of the Niagara™ and Dolphin® catheters for continuous renal replacement therapy

PURPOSE

The choice of vascular access catheter may affect filter life during continuous renal replacement therapy (CRRT); specifically, a new surface-modified catheter has been reported to possibly prevent thrombosis and catheter malfunction.

DESIGN AND SETTING

A sequential, controlled study in a tertiary ICU.

AIMS

To compare circuit life when CRRT was performed with a Bard®Niagara™ catheter or the surface-modified GamCath™ Dolphin® Protect 1320 catheter.

PATIENTS AND MEASUREMENTS

We studied 50 patients with acute kidney injury requiring CRRT, all delivered with catheters in the femoral position. We obtained information on age, gender, disease severity score (APACHE II and APACHE III), filter life, total heparin dose, hemoglobin concentration, platelet count, INR, and aPTT during CRRT.

RESULTS

We studied 341 circuits in 50 patients; 30 patients (140 circuits) used the Niagara and 20 patients (201 circuits) used the Dolphin catheter. Mean of circuit life in two groups was 14.9 hours and 13.1 hours, respectively (p=0.22). Patients using Niagara catheters had a more prolonged APTT (p<0.01) and lower platelet count (p=0.05), while heparin dose (p=0.22), and other anticoagulant treatment (p=0.73) were not significantly different. On Kaplan-Meier survival analysis, circuit life was not significant different between the two catheters (p=0.15).

CONCLUSIONS

The Niagara and Dolphin catheters appear to be broadly equivalent in terms of their impact on circuit life.

Repair of Damaged Connectors of Tunneled Cuffed Catheters with a Two-Piece Adaptor for Peritoneal Dialysis

Purpose

Although catheter use exposes the patient to several complications, tunneled cuffed catheters are widely applied for temporary or long-term vascular access. The aim of the study was to establish the rate of tunneled dialysis catheter damage and report our experience with breakage repair.

Methods

All 363 cuffed tunneled hemodialysis catheters inserted into 309 patients from May 2000 to December 2008 were followed up. When connector damage was encountered, repair with a two-piece adaptor for peritoneal dialysis was attempted.

Results

Mechanical breakage occurred in 33 (9.1%) of catheters with an incidence of 0.36/1000 catheter-days. The most frequent was connector damage, found in 25 cases (67.6%). Catheter repair using a peritoneal dialysis Luer adaptor was performed with good early and long-term outcome.

Conclusions

Tunneled catheter breakage is a relatively rare complication. Catheter repair using the adaptor for peritoneal dialysis is easy to perform, safe, and cost-effective.