Terminology and Common Issues in Pediatric CRRT

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Terminology and Common Issues in Pediatric CRRT

• John Gardner RN, BSN
• Nurse Manager
• Pediatric Nephrology Transplant
• DeVos Childrens Hospital
• Grand Rapids Michigan

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Over View

• Terminology
• Common issues
• Access
• Anticoagulation
• Extracorporeal circuit size
• Blood priming
• Hypothermia
• Staffing

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Terminology

• SCUF slow continuous ultrafiltration
• CAVH continuous arteriovenous
  hemofiltration
• CAVHD continuous arteriovenous
  hemodialysis

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Terminology

• CVVH continuous venovenous
  hemofiltration
• CVVHD continuous venovenous
  hemodialysis
• CVVHDF continuous venovenous
  hemodiafiltration

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CAVH/CVVH Convective Clearance

• CVVH/CAVH
• Convective clearance
• Replacement solutions
• Physiologic sterile solution that is either
  infused pre filter (NA) or post filter (outside
  of NA) that infused at a set rate (Qr)

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CAVHD/CVVHDDiffusive Clearance

• CVVHD/CAVHD
• Diffusive clearance
• Dialysate
• Physiologic sterile solution that is infused
  countercurrent to the blood flow rate (Qd)

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CAVHDF/CVVHDFConvective and Diffusive Clearance

• CVVHDF/CAVHDF
• Convective clearance
• Replacement solutions
• Diffusive clearance
• Dialysis solution

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Urea Clearance CVVH Vs CVVHD(Maxvold Et Al,
Crit Care Med, April 2000)

• Study design
• Fixed blood flow rate-4 mls/kg/min
• HF-400 (0.3 m2 polysulfone)
• Cross over for 24 hrs each to
  FRF or Dx flow at 2000
  mls/hr/1.73 m2
• TPN protein delivery at 1.5 gms/kg/day

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Comparison of Urea Clearance CVVH Vs
CVVHD(Maxvold Et Al, Crit Care Med April 2000)
p NS
Urea Clearance (mls/min/1.73 m2)
BFR 4 mls/kg/min FRF/Dx FR 2 l/1.73 m2/hr SAM
0.3 m2
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Vascular Access

• Properly functioning access is key to successful
  CRRT therapy
• Adequacy
• Filter life
• Decreased blood loss
• Staff satisfaction

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Ideal Catheter Characteristics

• Easy insertion
• Permits adequate blood flow without vessel
  damage, large diameter with shortest length
• Low resistance, decreased arterial and venous
  pressures
• Minimal technical flaws
• High recirculation rate
• Kinking

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Vascular Access Placement

• Femoral
• Internal jugular
• Sub-clavian (avoid if possible)
• Match catheter size to pt. Size and anotomical
  site
• One dual- or triple-lumen or two single lumen
  uncuffed catheters

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Common Causes of Poor Catheter Flow Rates

• Catheter tip position is the tip in proper
  placement?
• Kink
• Tight suture
• Clamp
• Decreased intrvascular volume
• Increased intrathoracic pressure
• Thrombosis or fibrin sheath formation

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Comparison of Upper Vs. Lower Body Location Line
Placement(Kendall 8 Fr 9 and 12 CmN 20 120
Treatments)
P value NS NS NS NS
Gardner et al, CRRT San Diego 1998
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Why Do We Need Triple Lumen Access?
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(Ca 0.4 x citrate rate 60 mls/hr)
(Citrate 1.5 x BFR 150 mls/hr)
Pediatr Neph 2002, 17150-154
(BFR 100 mls/min)
Normal Saline Replacement Fluid
Calcium can be infused in 3rd lumen of triple
lumen access if available.
Normocarb Dialysate

• ACD-A/Normocarb Wt range 2.8 kg 115 kg
• Average life of circuit on citrate 72 hrs (range
  24-143 hrs)

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Citrate running it
Arterial access
Venous access
Citrate infusion via y adaptor
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CaCl infusion line/or TPN/or Med line
Venous line
arterial line
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Anticoagulation

• Heparin
• Initial bolus 10 to 30 mg./ Kg
• Continuous infusion of 10 to 30 mg./Kg
• Maintain an activated clotting time (ACT) of
  180-210
• Risks of heparin anticoagulation
• Bleeding
• Thrombocytopenia

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Anticoagulation

• Citrate
• Citrate infusion to CRRT circuit
• Calcium infusion to to patient via separate
  central line
• Monitor post filter ionized calcium, adjust
  citrate infusion per protocol
• Monitor systemic ionized calcium, adjust calcium
  infusion per protocol
• Monitor for metabolic alkalosis and citrate loc

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Extracorporeal Circuit Volume

• Circuit volumes should be lt 10 of the patients
  intravascular blood volume
• Human blood volume formula
• lt 10kg 80ml/kg
• gt10kg 70ml/kg
• Removal of gt 10 blood volume extracorporeal can
  result in hemodynamic instability (shock)

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Blood Priming

• Indications
• Circuit volume gt10 of the patients blood
  volume
• Hemodynamic instability

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Complications of Blood Priming

• PRBC from the blood bank tend to have an
  increased potassium
• The HCT of PRBC is around 80
• A 50 dilution with normal saline or 5 albumin
  should be performed prior to circuit prime
• Bradykinin release syndrome may be seen with AN-
  69 membranes (brophy,et al 2001ajkd)
• System clotting

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Blood Priming Methods

• More concerning with AN-69 or membranes, less
  concerns with polysulphone membranes
• Zero balance ultrafiltration (Z-BUF)
• Normalizes electrolytes and improves acid-base
  status of the prime prior to pt connection by
  performing CVVH, CVVHD or CVVHDF for 30 minutes
• Hackbarth et al, Peds Neph, 2005 201328-33
• Bypass maneuver
• The patient is transfused with the PRBC at the
  same time and rate as the circuit is primed with
  the patients blood. The NS prime is wasted
• Brophy et al, am J kid Dis, 2001 Jul38(1)173-8

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Hypothermia

• Significant in pediatrics
• The smaller the more difficult
• Heat loss related to rate of blood flow and
  volume of blood in circuit
• Blood flow rate
• Higher blood flow rate decrease heat loss due to
  less time outside of the body

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Hypothermia Nursing Intervention

• External warming devices
• Radiant warmers
• Baer hugger
• Heating mattress
• Blood warmers
• Solutions heaters
• Monitoring
• Skin breakdown and patient temperature

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Staffing

• Staffing ratios
• Education
• System setup
• Pump management
• Program management

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A National Survey(April Tanner RN, Atlanta Ga,
PCRRT 3, Orlando 2004)

• An national review of current trends in CRRT
• An 18 question survey sent to pediatric centers
  that offer CRRT
• Free-standing or based in adult facility
• 42 centers responded

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Staffing Ratios
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Education

• Wide variety of teaching methods
• Didactic/hands on skills lab training occurs in
  69 of initial training sessions
• 12 require mentoring shifts
• 17 offer informal training
• 7 utilize bedside training methods

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Education

• Annual recertification - 43
• More frequent recertification occurs 26
• Smaller volume programs
• 19 of programs have no formal annual competency
  or recertification programs
• Many centers education programs are under review

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System Set-up
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Logistics and Coordination of System Set-up

• 11 of 42 centers have no formal 24/7 coverage
• In 93 of centers RNs manage the pump
• Dialysis, ECMO, and physicians make up the other
  
• Charge structure
• The dept.That sets up equipment receives revenue
  in majority of centers
• 21 of 42 centers also have daily charges
• Varied response as to where revenue goes

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Conclusion

• The education and competency of the bedside staff
  is essential for successful care of a child on
  CRRT
• No better teacher than the child
• Communication to colleagues throughout your
  program and throughout the world are critical in
  improvement in over all care

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Thank You