1. "Machinery and membranes"
Stefano Picca, MD
Department of Nephrology and Urology, Dialysis Unit
“Bambino Gesù” Pediatric Research Hospital, IRCCS
ROMA, Italy

2. MEMBRANES AND MACHINES : BASIC NEEDS IN CHILDREN
Biocompatibility
Filtration and absorption
Machines:
Accuracy and precision
Circuit low priming volume
Circuit inner pressures and resistance suitable for small catheters use

3. Symmetric (isotropic): Asymmetric (anisotropic):
SYNTHETIC MEMBRANES
Basically: adsorption enhanced
Symmetric (isotropic):
uniform pores dimension
throughout the entire
membrane thickness)
Asymmetric (anisotropic):
“skin layer” +
highly porous
supportive layer
Basically:
filtration
enhanced

4. Santoro, 2010

6. β2 MICROGLOBULIN REMOVAL
TOTAL
ABSORPTION
CONVECTION
Neri, 2012

7. REMOVAL OF SOLUTES AND MEDIATORS
Filter cutoff
CONVECTION/DIFFUSION
ABSORPTION
ß2 microglobulin
myoglobin
creatinine
inulin
IL-6
urea
sucrose
IL-8
albumin
ionic compounds
Vit B12
IL-1
TNF
MW (Daltons)

8. CAVH, 1984 CVVH: needs: increase blood flow manage fluid balance
Assenza di controllo Uf, riscaldatore non integrato.

10. Error up to 12.5%
2 pumps (pre-post filter)= error up to 25%

11. The real innovation: the load-cell
Equaline® Amicon, 1991

12. Baxter
BM25
Baxter
Aquarius
Baxter- Gambro
Prisma
Baxter- Gambro
Prismaflex

13. Two operating syringes (1), a high-flux polysulfone 0
Two operating syringes (1), a high-flux polysulfone m2 filter (2), a heparin syringe (3), pumped dialysate (4), a pressure transducer (5) and an air-detector (6), and self-primes with 4.3 ml of heparinised saline, giving a minimum operating volume of 9.3 ml
5 to 12.5 ml aliquots of blood from a single-lumen central venous line, passes and returns it across a dialysis filter, and then back to the baby.
At a blood flow rate of 20 ml/min, this processes 5 ml of blood each minute. The circuit has ultrafiltration from 0 to 60 ml/h is precisely controlled in 3.2 μl steps by differential syringe movements.

14. 101 circuits over 12 children
Pediatric Nephrology 2016
101 circuits over 12 children
Specifications:
PRIMING VOLUME 33 ml
Filter 0.12 m2
Qb ml/min
UF pump ml/h
Preinfusion replacement (30 ml/kg/h): external pump!!!

16. 120° 180° Blood flow and pressure into the blood pump segment
of the arterial line are not those measured by the machine
120°
180°
flow
volume
Courtesy of Medtronics-Bellco, modified

17. OPBG EXPERIENCE 12 neonates About 32 sessions 50% times 0.075 m2
Weight range kg
CVVH 100% pre
Qb 5-14 ml/min
Q rep ml/kg/h
NETQuf ml/h
Vasc access 6.5F, 4F
or two 20-24G cannulas
Courtesy of
Z. Ricci,
modified

18. In CVVHD: not bound to the CVVH filtration fraction
INFANT CRRT CIRCUITS: PRISMAFLEX ® vs CARPEDIEM®:
Operational Characteristics (CVVH)
Circuit blood priming volume
Blood flow rate
Blood flow rate resolution
Blood pressures range: art/ven
Max fluid loss/ session
(max 24 h)
Ultrafiltration (UF) rate
(based on FF=20%)
UF rate supervision
Gravimetric weight supervision accuracy
Fluid gravimetric control: max deviation from UF rate and scale control
Prismaflex HF20®
(0,20 m2)
59 ml
ml/min
2 ml
± 15 mmHg
No limit
ml/h
(up to 2500/h)
TMP alarm
≤ 7 g
±20 g immediate (i.e.: clamped bag) or
60 ml/last 3 hrs
Gain/loss control
Carpediem®
(0,25 m2)
41 ml
2-50 ml/min
1 ml
mmHg
1000 ml
0-600 ml/h
20% of Qb
1 g
±20 g (for exchange< 2L
(0,147 m2)
33 ml -
0-240 ml/h
(0,075 m2)
27 ml
0-150 ml/h
THE «REAL» DIFFERENCES (i.e.: CLINICAL CONSEQUENCES):
Pro-PRISMAFLEX®: Pro-CARPEDIEM®:
In CVVHD: not bound to the CVVH filtration fraction
No mandatory need for blood priming of circuit
Very low and accurate Qb: if malfuncioning CVC…

19. INFANT CRRT CIRCUITS: PRISMAFLEX ® vs CARPEDIEM®:
Clinical management
Modalities
Anticoagulation
Fluid Buffer
Heating
Catheters
Prismaflex HF20®
SCUF
CVVH
CVVHD
CVVHDF
Heparin/Citrate
Bicarbonate/Lactate
Optional
6,5F
7,5 cm
Carpediem®
Heparin
Lactate
None 4F
20G
THE «REAL» DIFFERENCES (I.E.: CLINICAL CONSEQUENCES):
Pro-PRISMAFLEX®: Pro-CARPEDIEM®:
CVVHDF control
Citrate…
Still waiting for Bicar-buffer…
Very small CVC in very small children…

21. TAKE HOME MESSAGE Tremendous improvement →
Extraordinary armamentarium now available
Clinical trials to investigate relation between technical advancement and clinical outcome needed

22. ACKNOWLEDGEMENTS All Dialysis Unit nurses
Stu Goldstein, Tim Bunchman and Claudio Ronco for precious advices and friendship through the years .

23. Dialysis Unit, “Bambino Gesù” Pediatric Hospital Roma, Italy.
Doctor:
S. Picca
Headnurse:
V. Bandinu
Nurses:
N. Avari
D. Ciullo
P. Iovine
P. Lozzi
L. Stefani
P. Vicerè
Nurse Coordinator:
M. D’Agostino

26. HEMO(DIA)FILTERS IN NEWBORNS AND CHILDREN: PAST AND PRESENT
MANUF.
FILTER
SURF. (m2)
MEMBR.
PRIMING (ml)
Gambro-Hospal
Miniflow10 
0.045
AN69
3.5
Amicon, then Minntech
Minifilter
0.07
Polysulfone 6
Bellco
Carpediem 1
0.075
27.2 (circuit)
Carpediem 2
0.147
33.5 (circuit)
Carpediem 3
0.245
41.5 (circuit)
Baxter-Gambro
HF20
0.2
Polyarylether-
sulfone (PAES)
60 (kit)
Baxter-Edwards
HF03
0.3 38
ST60
0.6
93 (kit)
HF07
0.7 54
ST100
1.0
149 (kit)   

27. The Alaris Pump module’s instrument accuracy is +/- 5% at rates between 1 and 999 mL/hr

29. Basis of the Nanostructure of membrane pores
Old Synthetic Membranes
Other membrane
Dead end pore
Stenotic pore
Improved Synthetic Membr
Conventional pores: ragged,
tortuous below surface
Nanocontrolled pores: smooth,
cylindrical: less resistance
Skin layer
Mix of small and large pores
Nanocontrolled Membrane
Standardized pore structure

32. ABSORPTION Electrical Mechanical Binding binding
In both cases, absorption depends on: Qb
Quf Qd
Surface
Initial concentration
Neri, 2012