Access in Pediatric CRRT Patrick D Brophy MD Pediatric Nephrology, Dialysis & Transplantation CS Mott Children’s Hospital University of Michigan

The System is Down due to poor Access!

My first choice is….

Access If you don’t have it you might as well go home. This is the most important aspect of CVVH therapy. Adequacy. Filter life. Increased blood loss. Staff satisfaction.

Vascular Access Ideal Catheter Characteristics Easy Insertion Permits Adequate Blood Flow without Vessel Damage Minimal Technical Flaws High Recirculation Rate Kinking Shorter and Larger Catheters SIZE DOES MATTER Lower Resistance Improved Bloodflow

Pediatric CRRT Vascular Access: Performance = Blood Flow Minimum 30 to 50 ml/min to minimize access and filter clotting Maximum rate of 400 ml/min/1.73m2 or 10-12 ml/kg/min in neonates and infants 4-6 ml/kg/min in children 2-4 ml/kg/min in adolescents

Venous Access for CRRT Match catheter size to patient size and anatomical site One dual- or triple-lumen or two single lumen uncuffed catheters Sites femoral internal jugular avoid sub-clavian vein if possible

Catheter Position No Right or Wrong Choice of Placement FACTORS Clinical expertise Body Habitus Other catheters (Citrate anticoag-triple preferred) Coagulopathy Intra-abdominal distension

Catheter Position Internal Jugular-Right- aim for RA to secure adequate BFR Subclavian-Patient mobility? Most frequent site of inadequate performance -catheter curves and abutts against SVC-Vein collapses against catheter due to positional/volume change Femoral- optimal position in tip of IVC

Vascular Access for Pediatric CRRT: Pros and Cons of Femoral Site Relatively larger vessel may allow for larger catheter higher flows Ease of placement No risk of pneumothorax Preserve potential future vessels for chronic HD Shorter femoral catheters with increased % recirculation Poor performance in patients with ascites/increased abdominal pressure Trauma to venous anastamosis site for future transplant

Vascular Access for Pediatric CRRT: Pros and Cons of IJ/SCV Site Tip placement in right atrium decreases recirculation Not affected by ascites Preserve potential vein needed for transplant SCV stenosis (SCV) Superior vena cava syndrome Risk of pneumothorax in patients with high PEEP Trauma to veins needed potentially for future HD access

Femoral versus IJ catheter performance 19 > 20 cm 7 < 20cm 13 IJ Qb 250 ml/min (ultrasound dilution) Recirculation measurement by ultrasound dilution method Little et al: AJKD 36:1135-9, 2000

Femoral versus IJ catheter performance Type Number Qb (ml/min) Recirculation(%) 95% CI Femoral 26 237.1 13.1* 7.6 to 18.6 > 20cm 19 233.3 8.5** 2.9 to 13.7 < 20cm 7 247.5 26.3** 17.1 to 35.5 Jugular 13 226.4 0.4* -0.1 to 1.0 * p<0.001 ** p<0.007 Little et al: AJKD 36:1135-9, 2000

Femoral versus IJ catheter performance: Pediatrics P value NS NS NS NS (Gardner et al, CRRT 1997 Quinton 8 Fr; n = 20; 120 Treatments)

Troubleshooting Access How can you tell if you have a problem before starting? Check placement first, then use syringe to test resistance and blood return. What if you have problems during treatment? Check line for kink, then assess patients position or need for sedation.

Access Clotting or sluggish catheter. Reason to replace catheter. tPA (tissue plasminogen activator). (Spry et al., Dialysis&Transplantation. Jan. 2001). Normal saline flush. Reason to replace catheter. Clotted catheter with no response to tPA. Exit site blood leakage with no response to pressure dressing. Severe kinked catheter. Bad re-circulation issues.

Pressures Arterial or outflow pressures Venous or return pressures High negative pressure = access problem. High positive pressure = filter problem. Moderate to high positive pressure + high return (venous) pressure = access problem. Venous or return pressures Moderate to high positive pressure + high arterial pressure = filter problem. High return pressure + moderate arterial pressure = access

Vascular Access for Pediatric CRRT: Some Final Thoughts Catheters with poor function will function poorly… over and over and over and over Balance between surgical/ICU expertise (preference?) and the necessary evils dictated by the patient high PEEP… femoral catheter? massive ascites… IJ catheter? available sites… are there any? Which vessel are you willing to traumatize?

Conclusions Poor Access-- May as well stop Choice- patient size and optimal flows Site- IJ/Femoral -recommended Care- Local standard + Lock issues- heparin Troubleshooting- anticipate, what is the machine saying? Happy Hemofiltering!

Thanks! Stu Goldstein Tim Bunchman Theresa Mottes Tim Kudelka Betsy Adams Tammy Kelly Robin Nievaard