1. Children’s Memorial Hospital Northwestern University
Hemofiltration Circuit Use Beyond 72 Hours in Pediatric Continuous Renal Replacement Therapy
Farah N. Ali, MD
Rajit Basu, MD
Jerome C. Lane, MD
Joan Fieldhouse, RN
Kathleen Ortiz
Children’s Memorial Hospital
Northwestern University
Chicago, Illinois

2. Background
During CRRT, hemofiltration circuits conventionally changed prior to 72 hrs
recommended by the manufacturer
prevent membrane or tubing rupture
Risk of
Hypotension
Potential Risk
of Rupture

3. Hypothesis
Lower flow rates in pediatric vs. adult CRRT might allow longer circuit duration
The use of circuits beyond 72 hrs in unstable pediatric CRRT patients can be performed safely, without increased morbidity or mortality

4. Methods Retrospective chart review Jan. 2003 to Oct. 2005
Procedure defined as:
initiation of CRRT in a new patient
resumption of CRRT after 24 hrs in a patient previously on CRRT
Procedures divided into 2 groups:
standard (all circuits ≤ 72 hrs)
extended (any circuits > 72 hrs)

5. Methods CRRT performed using standard protocol*
Citrate anticoagulation
CVVHDF mode
Normocarb for dialysate
Normocarb or Normal Saline for replacement
Blood flow 2-5 ml/kg/min
Dialysate 2000 ml/hr/1.73m2
Replacement 10-20% of total prescribed clearance
Prophylactic circuit change in stable patients prior to 72 hrs
*Bunchman et al. Pediatr Nephrol (2002) 17:150–154

6. Primary Diagnosis
n=103

7. Indication for CRRT
10.5%
79.5%
n=103

8. Results
103 CRRT procedures were performed for 85 patients during 33 months
Total of 402 circuits, of which 90 (22%) were used >72 hrs
For circuits >72 hrs, the mean duration of use was 5.5 days (SD 1.7, range 4-11)

9. All Circuits

10. Circuits > 72 hrs

11. Results 46 procedures in the extended group
57 procedures in the standard group
No significant differences between the groups:
Patient age
Primary diagnosis
CRRT indication
Anticoagulation
CRRT mode
Replacement fluid rate
Dialysate rate

12. Results
No difference in mortality between the groups (35% each group, p=0.86)
No incidents of membrane or tubing rupture in either group
Blood flow rates (BFR) were lower in the extended vs. standard group (60 vs. 70 ml/min, p=0.02)

13. Lower BFR in Extended Group
Unstable patients might require lower BFR to prevent hypotension
Lower BFR might produce less wear and tear on the circuit and permit longer circuit duration
Difference in BFR between the two groups, though statistically significant, might not be clinically significant

14. Discussion
Risk of extended circuit use vs. risk of hypotension during circuit change
More rigorous analysis of why circuits were changed at each time interval
Prospective study to evaluate a standard group vs. an extended group containing circuits only > 72 hrs

15. Conclusions
Use of hemofiltration circuits beyond 72 hours was not associated with increased mortality or increased incidence of circuit rupture.
Our data suggest a need to more carefully redefine the limits of prolonged circuit use in pediatric CRRT.

16. Future Work
More clearly define which patients benefit from prolonged circuit use
Examine other possible disadvantages to prolonged use
Insufficient solute clearance
Inadequate cytokine removal
Onset of new electrolyte imbalances
Examine other possible benefits of prolonged circuit use

17. Acknowledgments Jerome Lane, MD Craig Langman, MD Raj Basu, MD
Joan Fieldhouse, RN
Kathleen Ortiz
Division of Kidney Diseases at CMH
DaVita Children’s Dialysis Unit