Minimum 30 to 50 ml/min to minimize access and filter clotting
Maximum rate of 400 ml/min/1.73m 2 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
avoid sub-clavian vein if possible
No Right or Wrong Choice of Placement
Other catheters (Citrate anticoag-triple preferred)
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
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
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 Little et al: AJKD 36:1135-9, 2000 * p<0.001 ** p<0.007 -0.1 to 1.0 0.4* 226.4 13 Jugular 17.1 to 35.5 26.3** 247.5 7 < 20cm 2.9 to 13.7 8.5** 233.3 19 > 20cm 7.6 to 18.6 13.1* 237.1 26 Femoral 95% CI Recirculation(%) Qb (ml/min) Number Type
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.
Clotting or sluggish 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.
Arterial or outflow 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?
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?