basics of dialysis

7/22/2019 Basics of Dialysis

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Basics of Dialysis

Healthy Kidney

Location and Structure Functions

Diseased Kidney Causes

Symptoms and Sequelae

Renal Failure

Physical Basis

Transport through Membranes

Renal Replacement Hemodialysis

Peritonealdialysis

Kidney Transplantation

Situation in a

healthy human? Functioning ofsolute transport?

Functioning of

replacement therapy?Situation with adiseased kidney?


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Location and Structure

Cross-Section of the Kidney

Renal Vein

Renal Artery

Renal Pelvis

Ureter

Renal Medulla

Papilla

Renal Cortex

Branch of the

Renal Vein

Branch of the

Renal Artery

Nephron

Healthy Kidney Renal ReplacementPhysical BasisDiseased Kidney


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Nephron - Functional Unit of the Kidney

ProximalTubule

Glomerulus

AfferentArteriole

EfferentVenule

DistalTubule

CollectingDuct

Henles

Loop

CapillaryNetwork

UrinaryOutflow


PlasmaUltrafiltrate


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Details of a Glomerulus - The Membrane for Filtration

Detail of the Capillary Wall

Capillary Wall

- Filter-

ProximalTubule

Afferent

Arteriole

EfferentArteriole

CapillaryLoops

BowmansCapsule

Inside ofthe Capillary- Blood Side -

Outside ofthe Capillary- Urine Side -



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Bone Structure

Vitamin DActivation

CalciumBalance

Blood Formation

ErythropoietinSynthesis

Cardiac Activity

PotassiumBalance

Regulation of Blood pH

Recovery ofBicarbonate

Blood Pressure

Water Balance

SodiumRemoval

MetabolicEnd Products

Removal ofUrea, Creatinine etc.

Functions of the Kidney

Manifold Tasks of the Kidney

Functions



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0,1 l Water boundin stool

0,9 l Sweating andrespiration

1,5 l Urine

2,5 l Removal


Water Balance

Water intake andwater excretionmust be balanced.

This task is done

by the kidneysand by thirst.

0,3 l Water from

metabolism0,9 l Water contained

in solid food

1,3 l Beverages

2,5 l Intake+



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Filtration and Reabsorption

1500 lblood per day

through therenal arteries

180 lfiltrate per dayin the glomeruli

60 l

urine per dayat the end of theproximal tubules

20 lurine per day

at the beginning ofthe distal tubules

10 l

urine per dayat the end of thedistal tubules

1,5 l

urine per dayat the end of thecollecting ducts

real removal:1,5 l urine



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Causes for Kidney Failure

Examples

Heavy

Blood Loss

NephritisNeurogenicProblems

DiabetesCysts,

Anomalies

Accident / Trauma

Autoimmune

Diseases

Hypertension

Kidney Failure



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Location of the Cause?

Upstreamof the Kidney- prerenal -

Heavy Blood Loss

Stenosis of theRenal Artery

...

Downstreamof the Kidney- postrenal -

ProstaticHypertrophy

Renal Calculus

...

Within the Kidney- intrarenal -

Drugs Diabetes

InflammatoryDiseases

...



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Smoking

Hypertension

Diabetes

High Cholesterol

Overweight

Atherosclerosis


Risk Factors of Renal Failure

KidneyFailureHealthy Kidney Renal ReplacementPhysical BasisDiseased Kidney


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Symptoms and Signs of Renal Diseases

Early Signs of Renal Disease

Signs and Symptoms at the beginning of renal disease

are not specific, i.e. they occur also in other circum-

stances.

A medical examination and simple tests are able todiagnose a renal disease early. Thus the progress of the

renal disease can be stopped or at least slowed down.

Fatigue

Feeling of

Weakness

Blood inthe Urine

Protein in the Urine

(Heavily Frothing Urine)

EdemaVery Little Urin

orVery Much Urine



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Peripheral Edema

Reduction ofOxygen Intake

Fluid Lung

Fluid Overloadin the Body

Hypertension

Reduction ofCardiac Performance

Symptoms and Signs of Renal Diseases

Renal Failure, e.g. Water Removal

ReducedWater

Removal

Without therapy the fluid overload of the body and its consequencesare progressing, leading finally to the death of the patient.

Renal replacement therapy is life-saving.



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Renal Failure

Acute Renal Failure

Zllner,

Innere Medizin,

modified

Dialysis Treatments

CreatinineM/l

Time / days

Urinel/day

3. PolyuriaUncontrolled

Urine Quantities

(1 - 2 weeks)

1. DamageDamage to

Renal Tissue

(minutes to days)

2. Oliguria / AnuriaComplete Loss of

Renal Function

(up to 6 weeks)

4. Recoveryslow Recovery of

Renal Function

(several months)



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Physical Basis of Dialysis

Semipermeable Membrane

Medium sizedMolecules, e.g.

2-Microglobulin

Water Flow isEasily Possible

Erythrocyte,Red Blood Cell

Albumin, asExample of a BigProtein Molecule

Electrolytes

The semipermeable membrane functions similar to a fine sieve,only molecules that are small enough can pass.



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Diffusion

Start:

DifferentConcentrations

End:

EqualConcentrations

Diffusion is a consequence of the random movementof all molecules (Brownian Movement).

Time



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Ultrafiltration

Exertion of pressure on one side of the membrane produces filtration ofwater with solutes, as long as they can pass the membrane.

Time

Pressure



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Osmosis

Time

Different to diffusion the dissolved particles cannot pass themembrane, nevertheless the concentrations tend to equal out,thus water passes the membrane.



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Reverse Osmosis

Time

Pressure

Similar to ultrafiltration pressure is applied to one side of the membrane.Reverse osmosis is especially important for the purification

of water for the production of dialysate.


H di l i


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Hemodialysis

Flow Scheme Hemodialysis

Blood PumpAnti-Coagulation

Blood to

the Patient

Blood from

the Patient

Dialyzer

Fresh

Dialysate

Used

Dialysate


H di l i


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Hemodialysis

Flow Scheme Hemofiltration

Blood PumpAnti-Coagulation

Blood from

the Patient

Blood to

the Patient

Dialyzer

SterileInfusion

Solution

Ultrafiltrate

An exactbalancing ofinfused andultrafiltrated

volumes is

mandatorywhen using

Hemofiltration !


Hemodialysis


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Hemodialysis

Vascular access

TwinlumenCatheter

Dilated Vein- Shunt -

Connection:Vein and

Artery

Closure ofthe Distal

End of theVein

Jugular Vein(V. jugularisinterna)

Aorta

The vascular access using peri-pheral veins of the forearm has the

big advantage of long usage, but itneeds some weeks waiting timeafter the operation before the firstuse.

The access by a catheter inserted ina central vein can be immediately

used, but its lifetime is limited to afew weeks.


Hemodialysis


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Hemodialysis

Dialyzer

BloodInflow

DialysateOutflow

Bundle ofCapillaries inthe Housing

DialysateInflow

BloodOutflow

The dialysate flows outside of the capillaries,blood within the capillaries countercurrently.

Solute Transferacross theCapillary Walls


Peritoneal Dialysis


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Peritoneal Dialysis

How is Peritoneal Dialysis Done?

Peritoneum

PeritonealDialysis

Solution

Bag with Fresh Solution

ImplantedCatheter

Bag for Used Solution

Peritoneal dialysisis done by filling

specially composedperitoneal dialysis

solution into theabdominal cavity.

The solute transferbetween blood and

the solution happensby diffusion.

The water removalfrom the patient is

an osmotic process.


Peritoneal Dialysis


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Peritoneal Dialysis

Peritoneum as Semipermeable Membrane

Peritoneum

Peritoneal

DialysisSolution

Transport fromthe Solution

into the Blood

Epithelial Layer

Connective Tissue

Capillary

Transport from

the Blood intothe Solution

The solute transfer across the Peritoneum takes place in bothdirections, e.g. metabolic end products from the blood into the

solution and e.g. buffers in the opposite direction.




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Location of a Kidney Transplant

Aorta

Connection ofRenal Artery andVein to the PelvicVessels

Liver

Kidney Transplantin the Fossa Iliaca,Not at the Positionof Healthy Kidneys

Connection ofthe Ureter to the

Bladder of theRecipient




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Less Sequelae Mobility

No Fixed TimeSchedule

ContinuousTreatment


Advantages of Kidney Transplantation

Advantages of





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Suitability of

the Recipient

Shortage of

Organ Donors

Compatibilityof Tissues

Rejection

Immunosuppression


Problems of Kidney Transplantation

Disadvantages ofKidney Transplantation


Which Mode of Renal Replacement Therapy?


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Which Mode of Renal Replacement Therapy?

Each mode has its advantages and disadvantages.The selection is made in a discussion between patient and physician.

Hemodialysis Peritoneal Dialysis

KidneyTransplantation



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Thank you foryour kind attention.

basics of dialysis

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