Hd for residents (2) copy

1. HEMODIALYSIS IN CHILDREN

2. Dialysis principles
• Aim:
Clearance of solutes and ultrafiltration of fluid
• Clearance and ultrafiltration are 2 different processes that
can be separated at times
-flow off
-Ultrafiltration goal zero

3. Basic principle
Blood
Water
Solutes
Dialysate
Water
Solutes
Equilibration

5. Principle:
• Solute transfer across semipermeable membranes
along concentration gradients (diffusion)
• Counter current flow for optimized efficacy
Selectivity:
• Low (dialysate composition)
Efficacy:
• High for small molecular weight substances (urea,
creatinine, electrolytes, buffer...)
• Low for higher molecular weight substances (small
proteins, mediators, etc.)
Hemodialysis
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6. Principle:
- Solute transfer across semipermeable
membranes by pressure induced water flow
(convection, "solute drag")
- Volume substitution (pre or post filter)
Selectivity:
- Low
Efficacy:
- Improved for higher molecular weight
solutes (small proteins, mediators, etc.)
- Reduced for small molecular weight
substances (urea, creatinine, electrolytes,
buffer base)
Hemofiltration
6

7. DIFFUSION:
Solute from high to low concentration

8. ULTRAFILTRATION: Water driven by
pressure gradient  FLUID REMOVAL
CONVECTION
Solute
removal in
ultrafiltrate
↑ as uF ↑

9. 9

10. 10

11. IONs Concentration meq/l
Na+ 132-145
K+ 0 – 4
Cl- 103 – 110
HCO3- 0 – 40
Acetate 2 -37
Ca+ 0 -3.5
Mg+ 0.5 – 1
Glucose 0 -200mg/dl
Dialysate fluid composition
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12. Clinical:
• Pulmonary edema/ Desaturation
• Pericardial rub
• GI symptoms
• Altered Mental status
• Anasarca
• Bleeding tendency
• Anuria/ Oliguria
• Infection/sepsis
Indication of dialysis
Biochemical:
• Hyperkalemia
• Metabolic Acidosis
• Intoxication:
ASA, Alcohol,Lithium
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13. How to prevent dialysis disequilibrium
syndrome?
• PD is preferred if high urea levels
• Give loading dose of phenytoin 10-15mg/kg before
dialysis
• Give mannitol 2.5-5cc/kg IV infusion during the last 10
minutes of dialysis before turning flow off
• Use low flow rate in the first dialysis session
• Dialyse for 45 minutes in the first session and build up
after that

14. Ultrafiltration
• Ultrafiltration goal:
• Should not exceed 8% of the dry weight
• 1600 cc in a 20 kg patient
• Ultrafiltration rate:
10-20cc/kg/hr
• Ultrafiltration time:
UFG/UFR

15. Clearance
• As long as dialysate flows around the capillary tubes in
the dialyser, clearance will be ongoing
• Once flow off, no dialysate, no clearance
• Dependent on
• Blood flow rate 5–8 ml/kg/min
• Filter size
• Flow off
• Duration of dialysis session

17. 17

18. The
Kidney
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19. Membrane Pores
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20. Patient Catheter Size
Neonate 4-5 F
8-15 Kg 7 F
16-25 kg 8 F
25-30 Kg 9F
More than 30 Kg 9-11.5F
Catheter size

21. Filter Size
• F3 if less than 10kg
• F4 10-20kg
• F5 more than 20 kg
Dialyzer surface area/body surface area ratio =
0.8–1.0

22. Hemodialysis prescription
• Heparin or Wash:
Contraindications to heparinization:
• Hypertension
• Active bleeding
• Recent operation
• Thrombocytopenia
Fush dialyzer with 100–200 ml of isotonic saline every 15–30
min, increase ultra filtration rate to remove this additional fluid,
and carefully monitor venous pressure, drip chamber and
dialyzer for signs of clotting
• Types of Heparin used:
• Low molecular weight heparin:
• Unfractionated or regular heparin: Bolus 20U/kg, maintenance 0.1-
0.3U/kg/min (10U/kg/hr)

24. • Dialysate sodium should be equal to or more than serum
sodium
• Dialysate K concentration is adjusted according to
predialysis serum K levels
• Standard dialysate Ca concentration is 2.5 mEq/l (1.25
mmol/l); it can be adjusted if there is hypo- or
hypercalcemia

25. • HD should take place at least three times per week in
nearly all patients with end-stage renal disease
• Hypercatabolic and very young children may require more
frequent dialysis
• Reduction of dialysis frequency to twice per week
because of insufficient dialysis facilities is unacceptable

26. • Conventional HD uses a low-flux (small pore size)
membrane
• High-flux dialyzers are more efficient in removing solutes
that are larger than urea but may not be more efficient
than conventional hemodialysis in removing small solutes
• Blood prime with blood or 5 % albumin or isotonic saline if
circuit volume is >10 % of the patient’s estimated volume

27. • Hypotension
• Infection
• Bleeding
• Arrhythmia
• Dialysis Disequilibrium syndrome
• Anaphylaxis
• Air Embolism
• Contamination from water Aluminium, Chlorien
• Asthenia, weakness, Malnutrition
Dialysis Complications
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28. Intradialytic hypotension
• Common complication in HD
• Causes:
• Too rapid fluid removal (UF),
• Pre-dialysis antihypertensive medication,
• Bradykinin release
• Treat with:
• Cessation of ultra filtration, reduce blood flow,
• Head low position, Bolus of saline 5–10 ml/kg
• Discontinue dialysis if hypotension is severe
• Dry weight of the patient should be reassessed
• Avoid antihypertensives before dialysis session

29. • Another possible cause is the use of hypotonic (low
sodium) dialysate relative to the plasma
• Sodium remodeling,
• Online blood volume monitoring,
• Sequential ultra filtration,
• and use of intradialytic dobutamine (in patients with poor cardiac
reserve) may be beneficial

30. Other complications of HD
• Blood leak – This is due to entry of blood into the
dialysate circuit
• Dialyzer reactions/bioincompatibility – anaphylaxis or first
use syndrome, back pain, chest pain, pruritus
• Fever – pyrogens, presence of contaminants, infection
• Bleeding – check anticoagulation

31. Adequacy of dialysis
• Every patient with ESRD receiving thrice weekly HD
should have consistently:
• either urea reduction ratio (URR) > 65%
• or equilibrated Kt/V of >1.2 (or sp Kt/V of > 1.3) calculated from
pre- and post-dialysis urea values, duration of dialysis and weight
loss during dialysis
• Recent data which suggest that patients of low body
weight may have improved survival rates if the URR is
maintained above 70% or eKt/V is at least 1.4

32. Causes of Inadequate Dialysis
• Improper dialysis prescription
• Inadequate blood flow
• Reduction in treatment time
• Dialyzer clotting, leaks
• Recirculation
If lines are reversed during dialysis, 15–20 % increase in
recirculation is expected to occur

33. Indications for Kidney Biopsy
(a) Nephrotic syndrome
– Age of onset <1 year
– Atypical features such as gross hematuria, hypertension,
and abnormal renal functions
– Steroid resistance
– Prior to use of calcineurin inhibitors (CNI), for monitoring
while on CNI therapy
– Presence of associated systemic features

34. (b) Acute nephritic syndrome
– Absence of prior history of sore throat or pyoderma
– Nephritic–nephrotic presentations
– Progressive deterioration in renal functions
– Failure to normalize renal functions within 2–3 weeks
– Associated systemic features
– Recurrent nephritic features
– Persistence of gross hematuria or hypertension beyond
3–4 weeks
– Persistently low serum C 3 complement levels beyond 8–
12 weeks

35. (c) Hematuria and proteinuria
– Persistent hematuria and proteinuria beyond 3 months
– Recurrent disease
– Associated systemic features
– Positive family history of renal disease or hearing deficit
– Associated with low serum C3 complement level

36. (d) Acute kidney injury (AKI)
– Unexplained AKI with normal-sized kidneys
– In patients with suspicion of rapidly progressive
glomerulonephritis (histological diagnosis will guide therapy
and prognosis)
(e) Chronic kidney disease (CKD)
– CKD of undetermined etiology with normal-sized kidneys
(f) Post-transplant period
– Acute or chronic graft dysfunction
– Glomerulonephritis—recurrent or de novo
– Suspected infections like CMV, polyoma

37. Adequacy of the Renal Biopsy
• Light microscopy: >10 glomeruli
• Less than 10% incidence of missing focal lesions
• If 20 gloms or more less than 1% incidence of missing focal lesions
• Cortex and medullary regions
• Avoid glomeruli at the biopsy edge where there may be
compression artifacts

38. Immuno fluorescent (IF) Microscopy
• IgG and C3 in granular pattern along capillary loops and
in mesangium (e.g., acute postinfectious nephritis,
membranoproliferative glomerulonephritis, or lupus
nephritis)
• IgA in central mesangial areas (e.g., IgA nephropathy and
HSP nephritis)
• Linear deposition of IgG along the capillary loop wall (e.g.,
Goodpasture syndrome)
• Peritubular C4d deposition in acute humoral rejection of
the renal allograft

39. Electron Microscopy
• Confirm and refine localization of immune deposits to
classify glomerulonephritis (e.g., subepithelial “humps”
characteristic of acute postinfectious glomerulonephritis
or chronic membranous glomerulonephritis)
• Examine integrity of glomerular basement membrane
(specific diagnosis of Alport syndrome)

40. Lupus nephritis WHO classification
• Class I—normal by light microscopy
• Class II—mesangial involvement
• Class III—focal proliferative disease involving <50 % of
glomeruli
• Class IV—diffuse proliferative disease where >50 %
glomeruli are affected, with segmental (<50 % of
glomerular tuft) or global ( more than 50 % of the
glomerular tuft)
• Class V—membranous changes
• Class VI—advanced sclerosing lesions
• IF in active renal disease demonstrates a “full house”
pattern for IgA, IgG, IgM, C3, and C1q.

41. Thrombotic Microangiopathy
• These lesions are seen in HUS, TTP, malignant
hypertension
• Glomeruli show swollen endothelial cells with wrinkled
capillary walls, mesangiolysis, and luminal thrombi
• Arterioles show thrombo-necrotic lesions
• IF reveals fibrin deposits
• EM shows glomeruli with subendothelial widening with
accumulation of flocculent material

42. Alport Syndrome
• Light microscopy:
variable, ranging from unremarkable histology to
presence of interstitial foam cells and segmental sclerosis
• IF—nonspecific
• EM changes are diagnostic:
Thickening and thinning of GBM with
lamellations,basket weaving, interspersed with electron-
lucent zones within the basement membrane and
occasional rounded vesicular particles.