Hemofiltration Circuit Use Beyond 72 Hours in Pediatric Continuous Renal Replacement Therapy

1. 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 0

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