1. Peritoneal dialysis
Dr Ejaz Ahmed

6. Barrier to transport Mesothelium Interstitium Endothelium
Does not hinder transport
Interstitium
Hinders transport to some extent
Endothelium
Main barrier

7. Peritoneal transport principles
Diffusion
Depends on concentration gradient
Convection(filtration)
Depends on hydrostatic pressure and osmotic pressure

9. Diffusion Dr=p×a×c Dr=diffusion rate P=solute permeability
A=area of membrane
C=concentration gradient

10. Ultrafiltration UFr=p×a×(Hp+Op) UFr=ultrafiltration rate
P=permeability of water
A=surface area
Hp=hydrostatic pressure gradient
Op=osmotic pressure gradient

14. Material of catheter Silicone rubber Polyurethane Milky white material
Clear material

15. Catheter design Three portions Cuffs Intraperitoneal Extraperitoneal
External
Cuffs
Dacron material
One or two

17. Placement of catheter Open surgical placement
Peritoneoscopic placement
Blind placement

18. Proper location of catheter
Intraperitoneal portion
Directed towards pelvis
Cuff
Deep: within medial or lateral border of rectus sheath
Superficial: about 2 cms from skin exit

20. Composition of peritoneal dialysis fluid
Sodium(mmol/L)
Potasium(mmol/L)
0-2
Calcium(mmol/L)
Magnesium(mmol/L)
Chloride(mmol/L)
95-106
Lactate(mmol/L)
35-40
Bicarbonate(mmol/L) 34
Bicarbonate/lactate
25/15
Glucose(g/dl)
lcodextrin(g/dl)
7.5
Amino acids(g/dl)
1.1

21. Osmotic agents Low molecular weight High molecular weight
Glucose- 1.5%,2.5%,4.25%
Glycerol
Amino acids
High molecular weight
Albumin
Glucose polymer
peptides

28. Clearance Theoretical concept
“Volume of plasma from which all the substance has been removed and excreted into the urine per unit time”
Amount excreted = Urine volume x urine concentration
Excretion rate = Urine volume x urine concentration
Time

29. Clearance Example Clearance of a substance x
Excretion rate = 100 mg/ml x 1 ml = 100 mg/min
1 minute
Concentration of substance x in plasma = 1 mg/ml
Amount of plasma cleared per minute =
100 mg/min = 100 ml
1 mg/ml
Clearance = U x V
T x P

30. Principles of Clearance

31. Principles of Clearance

32. Clearance of Inulin

33. Substance
(L/wk)
kidney
H D
standard
High flux
CAPD
Urea
750
130 70
Vit B12
1200 30 80 40
Inulin 10 20
β2 Microg
1000
300
250

34. Small solute clearance
Urea clearance (Kt/V)
Normalised to total body water
Creatinine clearance (CrCl)
Normalised to body surface area

35. Total clearance Sum of Residual renal clearance
Peritoneal dialysis clearance

36. Method of calculating dialysate clearance of urea
24 hr collection of peritoneal dialysate effluent
Measure urea concentration in dialysate
Estimate total urea content
Urea concentration × volume of effluent
Calculate clearance
Kt =
Urea content in dialysate
Serum urea level

37. Method of calculating renal clearance of urea
Collect 24 hr urine
Measure urea concentration in urine
Estimate total urea content
Urea concentration × urine volume
Calculate renal clearence of urea
Kt =
Urea content in urine
serum urea level

38. Total and normalised clearance
Total clearance
Dialysate clearance + renal clearance
Normalised clearance (Kt/V)
Total body water

39. Calculate clearance
A 50 yr old man weighing 66 Kg has no urine output. He is on CAPD with four 2.5 L exchanges daily. His blood urea is 160 mg/dl and dialysate urea concentration of 24 hr collection is 140 mg/dl.calculate his daily clearance

40. Complications of peritoneal dialysis
Mechanical complication of catheter
Catheter obstruction/inadequate drain
Perforation and laceration of organs
Peritoneal catheter leaks
Infectious complications
Exit site infection
Peritonitis

41. Clinical presentation of peritonitis (percentages)
Cloudy fluid
98-100
Abdominal pain
67-97
Abdominal tenderness
62-79
Fever
34-36
Chills
18-23
Nausea
30-35
Vomiting
25-30
Diarrhoea
7-15

42. Route of entry for peritonitis
Touch contamination
Catheter related
Enteric
Haematogenous
Gynaecological

43. Organisms causing peritonitis
Gram-positive
Staphylococcus epidermidis
Staphylococcus aureus
Streptococcus
Enterococcus
Gram-negative
Fungal
Mycobacterial

44. Differential diagnosis of cloudy effluent
Infectious peritonitis
Eosinophilic peritonitis
Sclerosing peritonitis
Chylous ascites
Malignant ascites
Pancreatitis
Chemical peritonitis

45. Treatment of peritonitis
Antibiotics
Intraperitoneal route
Continuous
Intermitent
Intravenous route
Pain control

46. Outcome and sequelae Resolution-60-90% Abscess formation-1%
Transfer to hemodialysis(technique failure)-30%
Sclerosing peritonitis-1-2%
Death-1-6%

47. Types of peritoneal dialysis
Manual
CAPD-Continuous ambulatory peritoneal dialysis
Automated
CCPD-Continuous cyclic peritoneal dialysis
NIPD-Nocturnal intermittent peritoneal dialysis
TDP-Tidal peritoneal dialysis

49. TYPE CAPD 2-3 1-2 1-3 CCPD 1 3-4 NIPD 3-5 TDP 20 1-1.5 Day exchange
Night
Volume of exchange
CAPD
2-3
1-2
1-3
CCPD 1
3-4
NIPD
3-5
TDP 20
1-1.5

51. Peritoneal transport assessment
PET test
Concentration of creatinine in dialysis solution at four hrs
Concentration of creatinine in plasma at same time
Ratio of dialysate creatinine to plasma creatinine is calculated
Subject is classified into different transporter group

56. Improving outcomes: equal or better survival in first 2–3 years
Better preservation of RRF versus HD
Higher haemoglobin levels; less erythropoietin use
Preservation of vascular access for HD
Provides continuous UF for improved blood pressure and volume control
Better outcomes post-transplant
Less risk of acquiring blood borne virus (hepatitis C)
Patient benefits including more flexible holidays and travel and higher employment rates; better quality of life than maintenance HD
Ability to expand patient numbers in a dialysis centre with limited need for resources and major capital investments
Lower staff to patient ratio than maintenance HD
Less costly than maintenance HD