Access in Pediatric CRRT

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Access in Pediatric CRRT

• Patrick D Brophy MD
• Pediatric Nephrology, Dialysis Transplantation
• CS Mott Childrens Hospital
• University of Michigan

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The System is Down due to poor Access!
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My first choice is.
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Access

• If you dont 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.

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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

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Pediatric CRRT Vascular AccessPerformance
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

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(No Transcript)
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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

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Catheter Position

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

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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

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Vascular Access for Pediatric CRRT Pros and Cons
of Femoral Site
PROS
CONS

• 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

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Vascular Access for Pediatric CRRT Pros and Cons
of IJ/SCV Site
PROS
CONS

• 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

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Femoral versus IJ catheter performance

• 26 femoral
• 19 gt 20 cm
• 7 lt 20cm
• 13 IJ
• Qb 250 ml/min (ultrasound dilution)
• Recirculation measurement by ultrasound dilution
  method

Little et al AJKD 361135-9, 2000
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Femoral versus IJ catheter performance
Type Number Qb (ml/min) Recirculation() 95 CI
Femoral 26 237.1 13.1 7.6 to 18.6
gt 20cm 19 233.3 8.5 2.9 to 13.7
lt 20cm 7 247.5 26.3 17.1 to 35.5
Jugular 13 226.4 0.4 -0.1 to 1.0
plt0.001 plt0.007
Little et al AJKD 361135-9, 2000
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Femoral versus IJ catheter performance
Pediatrics
P value NS NS NS NS
(Gardner et al, CRRT 1997Quinton 8 Fr n 20
120 Treatments)
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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.

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Access

• Clotting or sluggish catheter.
• tPA (tissue plasminogen activator).
• (Spry et al.,
  DialysisTransplantation. 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.

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Pressures

• 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

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Vascular Access for Pediatric CRRTSome 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?

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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!

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Thanks!

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