Pediatric CRRT: The Prescription

1
Pediatric CRRT The Prescription

• Stuart L. Goldstein, MD
• Professor of Pediatrics
• Baylor College of Medicine

2
Whats in a CRRT Prescription?

• Indication (Why? Who? When?)
• Technical Aspects (What?)
• Nutrition (Maxvold)
• Anticoagulation (Brophy)
• Access (Bunchman)
• CRRT Delivery (How?)
• Blood pump flow rates
• Modality
• Priming
• Dose

3
Why CRRT in AKI?

• Critically ill patient
• Advantages
• Slower blood flows
• Slower UF rates
• UF rates can be prescriptive (versus PD)
• Adjust UF rates with hourly patient intake
• Increased cytokine (bad humors) removal?
• Disadvantages
• Increased cytokine (good humors) removal?
• Non-dialysis personnel with many other bedside
  responsibilities required to monitor circuit

4
(No Transcript)
5
When Should CRRT Be Started?

• Standard AKI criteria not responsive to medical
  therapy OR only preventable with limiting
  adequate nutrition
• Uremia
• Hyperkalemia
• Acidosis
• Fluid Overload
• Prevention of worsening fluid overload?

6
Timing of Pediatric RRT

• No adequate definition for timing of initiation
  
• Absence of a generally accepted, validated and
  applied AKI definition has impeded the adequate
  investigation of this question
• The decision to initiate RRT affected by
• Strongly held physician beliefs
• Patient characteristics
• Organizational characteristics

7

• Retrospective evaluation of 226 children who
  received RRT for AKI from 1992-1998
• Pressor use surrogate marker for patient severity
  of illness
• Survival defined at PICU discharge

8
(No Transcript)
9
Percent Fluid Overload Calculation


Fluid In - Fluid Out ICU Admit Weight
100
FO at CVVH initiation
Fluid In Total Input from ICU admit to CRRT
initiation Fluid Out Total Output from ICU
admit to CRRT initiation
10

• Lesser FO at CVVH (D) initiation was associated
  with improved outcome (p0.03)
• Lesser FO at CVVH (D) initiation was also
  associated with improved outcome when sample was
  adjusted for severity of illness (p0.03
  multiple regression analysis)

11
Fluid Overload Thresholds at CRRT Initiation and
Mortality
Author FO Threshold Outcome
Goldstein Fluid thresholds not assessed Fluid thresholds not assessed
Gillespie 10 OR death 3.02 gt 10 FO
Foland 10 increment 1.78 OR death for each 10 FO increase
Goldstein (ppCRRT) 20 lt20 FO 58 survival gt20 FO 40 survival
Hayes 20 OR death 6.1 gt 20 FO
12
The Evolution of Idea to Practice Paradigm
Registry
Single center study
Randomized Trial
13
Prospective Pediatric CRRT (ppCRRT ) Registry
Phase 1 Design

• Collect prospective data from 10 pediatric
  centers treating 15 to 20 patients annually (376
  patients over 5 years)
• Each center follows own institutional practice
• Patient selection
• Initiation and termination
• Anti-coagulation protocols
• Convection versus diffusion versus
  hemodiafiltration
• Fluid composition

14
ppCRRT FO Threshold
Sutherland S. for the ppCRRT AJKD 2010
15
Pediatric CRRT Circuit Priming

• Heparinized (5000 units/L) for most patients
• Smaller patients require blood priming to prevent
  hypotension/hemodilution
• Circuit volume gt 10-15 patient blood volume
• Packed RBCs
• Citrated low ionized calcium
• Acid load
• Potassium load

16
Bradykinin Release Syndrome

• Mucosal congestion, bronchospasm, hypotension at
  start of CRRT
• Resolves with discontinuation of CRRT
• Thought to be related to bradykinin release when
  patients blood contacts hemofilter
• Most common with AN-69 membranes
• Exquisitely pH sensitive

17
Technique Modifications to Prevent Bradykinin
Release Syndrome

• Buffered system
• THAM, CaCl, NaBicarb to PRBCs
• Bypass system
• prime circuit with saline, run PRBCs into patient
  on venous return line
• Recirculation system
• recirculate blood prime against dialysate

18
(No Transcript)
19
Recirculation Plan Qb 200ml/min Qd
40ml/min Time 7.5 min
20
Does Modality Make A Difference?

• Equal clearance of smaller molecules
• Middle and large molecule clearance enhanced by
  convection

21
(No Transcript)
22
Membrane Selectivity
Courtesy of J. Symons
23
Clearance Convection vs. Diffusion
24
Solute Molecular Weight and Clearance
Solute (MW) Sieving Coefficient Diffusion
Coefficient Urea (60) 1.01 0.05 1.01
0.07 Creatinine (113) 1.00 0.09 1.01
0.06 Uric Acid (168) 1.01 0.04 0.97
0.04 Vancomycin (1448) 0.84 0.10 0.74
0.04 Plt0.05 vs sieving coefficientPlt0.01
vs sieving coefficient
25
Flores FX et al CRRT 2006 abstract
26
ppCRRT Pediatric Sepsis Outcome Data

• 57/102 (56) pts survived.
• Ventilated pts had similar survival rate as
  non-ventilated pts (53 vs. 68, p0.1).
• There was no significant difference in the
  survival rate among CRRT modalities.
• Tendency toward better survival with convective
  therapies

Flores FX et al CRRT 2006 abstract
27
Survival Based on CRRT Modality?

• Confounded
• Center
• Timing of initiation
• Sepsis definition not standardized
• Suggestive
• If all else equal, why not convect?

Flores FX et al CRRT 2006 abstract
28
Dialysate/ Ultrafiltration Rates

• The UF rate/plasma flow rate BFRx(1-HCT) ratio
  should lt 0.35-0.4 in order to avoid filter
  clotting (Golper AJKD 6 373-386,1985)
• Dialysate or effluent flow rates ranging from
  20-30 ml/min/m2 (2000ml/1.72m2/hr) are usually
  adequate (experiential but consistent with adult
  data)

29
Dose Pediatric CRRT

• No published data to suggest an adequate or
  optimal CRRT dose in children
• Small molecule clearance and electrolyte
  homeostasis is generally easy to achieve
• Is more better?
• Nutrition balance (what are we removing that wed
  like to leave behind?)