Hemodialysis

in

children

general

practical

guidelines

Over

the

past

years

children

have

benefited

from

major

improvements

in

both

technology

and

clinical

management

of

dialysis

Morbidity

during

dialysis

sessions

has

decreased

with

seizures

being

exceptional

and

hypotensive

episodes

rare

Pain

and

discomfort

have

been

reduced

with

the

use

of

chronic

internal

jugular

venous

catheters

and

anesthetic

creams

for

fistula

puncture

Non-invasive

technologies

to

assess

patient

target

dry

weight

and

access

flow

can

significantly

reduce

patient

morbidity

and

health

care

costs

The

development

of

urea

kinetic

modeling

enables

calculation

of

the

dialysis

dose

delivery

Kt/V

and

an

indirect

assessment

of

the

intake

Nutritional

assessment

and

support

are

of

major

importance

for

the

growing

child

Even

if

the

validity

of

these

urea

only

data

is

questioned

their

analysis

provides

information

useful

for

follow-up

Newer

machines

provide

more

precise

control

of

ultrafiltration

by

volumetric

assessment

and

continuous

blood

volume

monitoring

during

dialysis

sessions

Buffered

bicarbonate

solutions

are

now

standard

and

more

biocompatible

synthetic

membranes

and

specific

small

size

material

dialyzers

and

tubing

have

been

developed

for

young

infants

More

recently

the

concept

of

ultrapure

dialysate

i.e.

free

from

microbiological

contamination

and

endotoxins

has

developed

This

will

enable

the

use

of

hemodiafiltration

especially

with

the

on-line

option

which

has

many

theoretical

advantages

and

should

be

considered

in

the

case

of

maximum/optimum

dialysis

need

Although

the

optimum

dialysis

dose

requirement

for

children

remains

uncertain

reports

of

longer

duration

and/or

daily

dialysis

show

they

are

more

effective

for

phosphate

control

than

conventional

hemodialysis

and

should

be

considered

at

least

for

some

high-risk

patients

with

cardiovascular

impairment

In

children

hemodialysis

has

to

be

individualized

and

viewed

as

an

integrated

therapy

considering

their

long-term

exposure

to

chronic

renal

failure

treatment

Dialysis

is

seen

only

as

a

temporary

measure

for

children

compared

with

renal

transplantation

because

this

enables

the

best

chance

of

rehabilitation

in

terms

of

educational

and

psychosocial

functioning

In

long

term

chronic

dialysis

however

the

highest

standards

should

be

applied

to

these

children

to

preserve

their

future

cardiovascular

life

which

might

include

more

dialysis

time

and

on-line

hemodiafiltration

with

synthetic

high

flux

membranes

if

we

are

able

to

improve

on

the

rather

restricted

concept

of

small-solute

urea

dialysis

clearance

Introduction

The

European

Paediatric

Dialysis

Working

Group

was

established

in

by

pediatric

nephrologists

from

different

European

countries

with

a

major

interest

in

dialysis

The

group

has

already

published

guidelines

mainly

on

peritoneal

dialysis

-LSB-

-RSB-

Hemodialysis

practices

for

children

have

improved

over

the

ensuing

years

especially

because

of

technological

developments

and

the

evolution

from

minimum/adequate

to

optimum/maximum

dialysis

prescription

-LSB-

-RSB-

Therefore

new

general

recommendations

seem

necessary

These

guidelines

were

initiated

and

discussed

at

meetings

of

the

group

and

refined

by

e-mail

discussion

to

develop

a

consensus

of

opinion

on

the

basis

of

cumulative

clinical

experience

and

reported

studies

This

paper

will

discuss

the

main

factors

affecting

hemodialysis

prescription

and

management

in

children

In

some

European

countries

hemodialysis

-LRB-

HD

-RRB-

is

often

preferred

for

children

over

the

age

of

five

years

-LSB-

-RSB-

In

contrast

peritoneal

dialysis

-LRB-

PD

-RRB-

is

offered

to

the

younger

children

especially

under

the

age

of

two

years

or

weighing

less

than

kg

A

multicenter

European

study

has

however

found

that

of

children

were

older

than

five

years

when

peritoneal

dialysis

was

started

-LSB-

-RSB-

Factors

ranked

as

first

priority

for

choice

of

therapy

-LSB-

-RSB-

included

age

of

the

child

-LRB-

-RRB-

parent

choice

-LRB-

-RRB-

distance

from

unit

-LRB-

-RRB-

patient

choice

-LRB-

-RRB-

social

condition

-LRB-

-RRB-

and

unable

to

do

one

mode

-LRB-

-RRB-

Nevertheless

important

differences

appear

in

the

individual

countries

Usually

however

HD

is

not

offered

to

children

less

than

years

old

unless

there

are

important

contra-indications

for

PD

-LSB-

-RSB-

For

older

children

HD

is

applied

for

drop-outs

from

the

PD

program

or

if

there

are

medical

-LRB-

rare

-RRB-

or

psychosocial

-LRB-

more

often

-RRB-

reasons

for

not

performing

PD

Choosing

a

mode

of

dialysis

either

HD

or

PD

for

a

child

requires

consideration

among

other

factors

of

the

probable

impact

of

either

mode

of

dialysis

on

the

maintenance

of

residual

renal

function

-LRB-

RRF

-RRB-

because

of

its

specific

impact

on

patient

outcome

Although

there

is

no

general

consensus

peritoneal

dialysis

has

been

associated

with

less

risk

of

RRF

loss

-LSB-

-RSB-

Overall

the

choice

of

the

mode

of

dialysis

is

just

a

part

of

the

integrated

care

model

each

child

should

be

considered

for

a

combined

dialysis-transplantation

program

Provision

of

adequate

vascular

access

remains

the

single

greatest

obstacle

to

successful

HD

especially

in

infants

Unlike

in

the

USA

where

patients

frequently

use

a

central

catheter

for

vascular

access

-LSB-

-RSB-

in

Europe

an

arteriovenous

fistula

is

the

most

common

vascular

access

for

chronic/long

term

dialysis

-LSB-

-RSB-

According

to

the

K-DOQI

guidelines

the

percentage

of

catheters

in

a

dialysis

unit

for

adults

should

be

less

than

although

many

pediatric

centers

do

not

meet

this

standard

because

of

the

difficulty

of

creating

fistulas

in

smaller

children

especially

in

children

less

than

years

of

age

During

the

past

two

decades

there

have

been

many

improvements

in

the

technology

-LSB-

-RSB-

bicarbonate

used

as

buffer

in

the

dialysis

solution

volumetrically

controlled

ultrafiltration

smaller

dialysis

lines

and

synthetic

membranes

useful

even

for

babies

modeling

of

ultrafiltration

rate

and

dialysate

composition

on

line

hemodiafiltration

and

the

concept

of

ultrapure

dialysate

i.e.

sterile

and

pyrogen

free

Non

invasive

technologies

to

assess

patient

target

dry

weight

and

access

flow

offer

a

potential

decrease

in

dialysis

morbidity

and

costs

-LSB-

-RSB-

Recently

marketed

medications

to

improve

anemia

for

example

erythropoïetin

even

darbepoietin

and

iron

infusion

contribute

to

the

clinical

improvement

of

the

hemodialysis

session

-LSB-

-RSB-

Dialysis

adequacy

quantification

by

urea

kinetic

modeling

enables

a

more

specific

approach

to

dialysis

dosing

and

indirect

assessment

of

protein

intake

despite

the

limited

value

of

small-solute

clearance

-LSB-

-RSB-

Nevertheless

it

has

been

widely

accepted

that

clinical

results

depend

at

least

in

part

on

the

dialysis

dose

delivered

-LSB-

-RSB-

In

fact

a

single

center

experience

shows

the

beneficial

impact

of

longer

dialysis

duration

on

clinical

outcome

in

children

-LSB-

-RSB-

However

it

is

now

becoming

more

and

more

evident

that

increasing

the

dialysis

dose

when

delivered

only

three

times

weekly

is

an

unphysiological

strategy

self

limited

by

the

potential

increased

risk

of

hemodynamic

and

electrolytic

disturbances

-LSB-

-RSB-

In

adult

care

there

is

a

growing

interest

in

the

use

of

daily

dialysis

because

long

term

experience

has

shown

good

results

-LSB-

-RSB-

In

children

only

a

pilot

study

in

one

center

supported

the

positive

impact

of

daily

dialysis

in

very

non-compliant

adolescents

-LSB-

-RSB-

In

children

the

hemodialysis

prescription

should

be

individualized

Choice

of

the

mode

of

hemodialysis

should

take

into

account

the

presumed

waiting

time

before

kidney

transplantation

as

a

justification

for

the

use

of

the

best

available

mode

having

the

highest

cost

and

conversely

being

supported

by

very

limited/preliminary

studies

only

-LSB-

-RSB-

The

importance

of

the

choice

of

material

used

for

dialysis

and

its

application

should

not

obviate

the

need

for

management

of

the

entire

child

with

ESRF

especially

regarding

optimum

nutrition

-LSB-

-RSB-

Because

dialysis

per

se

is

not

able

to

correct

completely

the

numerous

functions

of

the

kidney

lost

during

ESRF

medications

and

dietary

recommendations

are

needed

in

children

on

hemodialysis

-LSB-

-RSB-

Recombinant

growth

hormone

is

often

needed

considering

the

growth

velocity

rate

of

children

on

chronic

dialysis

-LSB-

-RSB-

Guideline

the

dialysis

unit

hemodialysis

should

be

delivered

in

a

pediatric

dialysis

center

with

a

multidisciplinary

support

team

which

supports

individualized

and

integrated

therapy

nutrition

growth

and

educational

support

are

of

major

importance

Because

of

the

specific

needs

of

children

hemodialysis

should

be

delivered

at

the

best

and

probably

only

in

a

pediatric

dialysis

unit

-LSB-

-RSB-

This

includes

the

treatment

of

adolescents

up

to

the

age

of

years

and

beyond

depending

upon

their

physical

and

psychological

development

and

transition

arrangements

to

adult

units

-LSB-

-RSB-

Taking

care

of

a

child

with

ESRF

necessitates

an

engaged

team

consisting

of

doctors

nurses

dietician

psychologist

school

teacher

play

therapist

and

social

worker

-LSB-

-RSB-

This

second

family

or

support

team

should

be

multidisciplinary

and

immediately

available

to

the

chronically

ill

child

both

close

and

distant

enough

to

stimulate

normal

family

life

supporting

a

proper

-LRB-

school

-RRB-

education

leaving

all

possibilities

open

for

full

integration

into

society

in

the

future

Hemodialysis

in

contrast

with

peritoneal

dialysis

is

usually

performed

in

an

hospital

setting

with

a

frequency

of

three

times

per

week

for

most

patients

This

frequency

may

be

increased

to

address

the

specific

needs

of

babies

and/or

adolescents

requiring

more

dialysis

-LSB-

-RSB-

Guideline

water

quality

adequate

in

terms

of

biochemical

composition

free

from

microbiological

contamination

The

dialysis

machine

needs

water

for

dialysate

production

adequate

in

terms

of

biochemical

composition

and

free

from

microbiological

contamination

i.e.

germs

and

endotoxins

-LRB-

Table

-RRB-

Water

purification

depends

on

the

disposable

water

quality

Usually

filtration

with

charcoal

and

the

small

sieving

coefficient

associated

with

reverse

osmosis

produces

water

for

dialysis

in

accordance

with

the

recommendations

-LSB-

-RSB-

-LRB-

Table

-RRB-

Currently

all

new

dialysis

machines

have

the

ability

to

filter

the

dialysate

through

a

high

flux

membrane

which

increases

microbiological

purity.Table

Water

contaminants

and

associated

complicationsaDissolved

organic

materialComplicationsContaminants

Pesticides

herbicidesNo

documentation

during

dialysis

Chloramines

chlorine

compoundsSevere

hemolytic

anemiaBacteria

and

pyrogens

BacteriaBacteremia

or

septicemiaFever

chills

shakingHypotension

and

death

PyrogensPyrogenic

reaction-feverChills

uncontrollableShaking

vomiting

hypotensionaNot

exhaustiveTable

Definitions

of

water

and

dialysate

quality

-LRB-

levels

given

as

an

upper

limit

for

water-quality

definition

-LSB-

-RSB-

-RRB-

Bacterial

growth

-LRB-

cfu

mL

-RRB-

Endotoxin

-LRB-

EU

mL

-RRB-

Cytokine-inductionAAMI

European

pharmacopoeiaRegular

In

hemodiafiltration

using

an

on-line

technique

-LSB-

-RSB-

with

direct

production

from

the

dialysate

of

the

hemofiltration

substitution

fluid

the

dialysate

benefits

from

double

ultrafiltration

producing

an

ultrapure

dialysate

which

is

sterile

and

endotoxin

free

at

least

at

detectable

levels

This

ultrapure

dialysate

should

limit

the

risks

related

to

microbiological

contamination

i.e.

inflammatory

process

induction

with

both

acute

and

chronic

consequences

-LSB-

-RSB-

This

level

of

ultrapure

dialysate

is

also

required

for

synthetic

high-flux

membrane

use

even

or

especially

when

used

in

a

conventional

hemodialysis

mode

Decontamination

or

sterilization

by

chemical

agents

or

by

heating

should

be

performed

in

line

with

water

before

final

dialysate

production

by

the

dialysis

machine

by

filtration

and

osmosis

installation

and

water

distribution

without

any

break

between

sterilization

and

final

dialysate

Quality

control

of

the

water

for

the

dialysate

should

be

performed

regularly

with

regard

to

chemical

composition

-LRB-

at

least

once

per

year

-RRB-

and

final

dialysate

purity

should

be

assessed

with

regard

to

bacteria

and

endotoxins

-LRB-

more

regularly

depending

in

part

on

the

mode

of

dialysis

weekly

for

high-flux

membrane

use

-RRB-

-LRB-

Table

-RRB-

-LSB-

-RSB-

Guideline

the

dialysis

machine

volumetric

ultrafiltration

control

option

for

both

single

and

double-needle

dialysis

In

the

last

decade

numerous

innovations

in

equipment

have

been

developed

by

different

manufacturers

-LSB-

-RSB-

But

the

relevance

to

child

outcome

remains

unknown

because

of

the

absence

of

sufficient

controlled

study

results

Nevertheless

the

following

innovations

seem

essential

dialysate

production

by

double

dilution

pumps

using

volumetric

ultrafiltration

control

and

blood

pumps

with

double

pumps

available

for

single-needle

dialysis

Other

high-tech

innovations

only

deserve

mention

because

of

their

limited

application

in

expert

centers

individual

modeling

of

the

dialysis

session

with

monitoring

of

ultrafiltration

and

dialysate

solute

concentration

-LRB-

i.e.

sodium

bicarbonate

-RRB-

polyvalency

machine

which

enables

not

only

conventional

dialysis

but

also

hemofiltration

and

hemodiafiltration

providing

the

highest

standard

in

terms

of

tolerance

and

efficiency

-LSB-

-RSB-

Newer

dialysis

machines

provide

monitoring

of

hematocrit

variation

as

a

major

promising

innovation

-LSB-

-RSB-

and

direct

urea

kinetic

monitoring

-LSB-

-RSB-

There

is

a

restricted

offer

for

blood

thermal

monitoring

to

avoid

loss

of

calories

to

the

dialysate

or

to

prescribe

cooled

dialysate

-LSB-

-RSB-

All

these

innovations

enable

individualized

hemodialysis

for

the

children

but

their

regular

application

should

take

into

consideration

the

balance

between

the

expected

benefits

and

the

costs

Guideline

blood

lines

available

in

infants/babies

size

biocompatible

material

A

range

of

blood

lines

are

available

for

dialysis

of

babies

to

dialysis

of

the

largest

adolescent

They

should

be

considered

for

their

biocompatibility

type

of

sterilization

-LRB-

ethylene

oxide-free

-RRB-

and

the

blood

volume

required

-LSB-

-RSB-

Guideline

principles

of

blood

purification

small

solute

clearance

and

more

from

diffusion

process

-LRB-

urea

-RRB-

to

convection

-LRB-

other

uremic

toxins

middle

molecules

-RRB-

mass

transport

hemodiafiltration

is

an

option

to

consider

to

obtain

maximum

dialysis

efficiency

Uremic

toxin

extraction

in

dialysis

-LSB-

-RSB-

is

related

to

a

combination

of

the

diffusion

process

and

convection

mass

transport

-LRB-

Table

-RRB-

In

hemodialysis

-LRB-

HD

-RRB-

blood

purification

depends

mostly

on

a

diffusion

process

secondary

to

a

concentration

gradient

which

ensures

the

best

elimination

of

small

molecules

-LRB-

urea

-RRB-

HD

clearance

-LRB-

KHD

-RRB-

correlates

directly

with

blood

flow

rate

In

hemofiltration

-LRB-

HF

-RRB-

uremic

toxin

extraction

is

mostly

dependent

on

convection

mass

transport

secondary

to

a

pressure

gradient

which

optimizes

the

elimination

of

both

low

and

middle-molecular-weight

compounds

HF

clearance

-LRB-

KHF

-RRB-

directly

correlates

with

ultrafiltration

flow

rate

which

is

limited

by

the

blood

flow

rate

In

the

post

dilution

mode

i.e.

replacement

fluid

in

the

venous

line

chamber

located

after

the

dialyzer

membrane

maximum

filtrate

flow

rate

is

less

than

half

the

blood

flow

rate

it

is

usually

one

third

to

limit

the

risks

of

excessive

hemoconcentration

In

the

predilution

mode

i.e.

replacement

fluid

perfusion

in

the

arterial

line

chamber

which

is

situated

before

the

dialyzer

membrane

maximum

filtrate

flow

rate

should

be

two

thirds

of

or

equal

to

the

blood

flow

rate

Hemodiafiltration

-LRB-

HDF

-RRB-

combines

HD

and

HF

simultaneously

which

enables

blood

purification

by

both

a

diffusive

process

and

convective

mass

transport

HDF

clearance

-LRB-

KHDF

-RRB-

in

post-dilution

mode

is

measured

by

use

of

the

Granger

formula

-LSB-

-RSB-

Table

Dialyzer

membrane

permeability

diffusion

and

convectionDiffusion

processConvection

mass

transportMembrane

areaUltrafiltrate

flow

-LRB-

QUF

-RRB-

Mass-transport

coefficientHydraulic

permeabilityConcentration

gradientTransmembrane

pressure

-LRB-

TMP

mmHg

-RRB-

Blood

flow

extraction

coefficientMembrane

areaSieving

coefficient

-LRB-

S

-RRB-

ci

and

co

are

inlet

and

outlet

solute

concentrationsMolecular

permeability

CUF

is

the

ultrafiltrate

solute

concentration

-LRB-

postdilution

-RRB-

-LRB-

predilution

-RRB-

KHD

is

hemodialysis

clearance

and

KHF

is

hemofiltration

clearance

On

replacement

of

QUF

S

by

KHF

and

Qb

by

Kmax

-LRB-

maximum

achieved

clearance

-RRB-

the

formula

for

KHDF

becomes

Thus

it

is

clear

that

in

terms

of

blood

purification

KHDF

enhances

the

clearance

of

a

uremic

toxin

if

HF

or

HD

clearances

are

lower

than

the

Kmax

-LRB-

equal

to

the

blood

flow

rate

-RRB-

HDF

with

a

highly

permeable

membrane

is

as

efficient

as

HD

for

low-molecular-weight

compounds

but

is

more

efficient

than

HF

for

low-molecular-weight

compounds

-LSB-

-RSB-

Moreover

HDF

besides

its

blood

purification

efficiency

is

associated

with

a

lower

intradialytic

morbidity

rate

-LSB-

-RSB-

as

is

HF

-LSB-

-RSB-

On-line

HDF

-LSB-

-RSB-

in

which

filtered

dialysate

free

of

toxins

and

pyrogens

is

used

as

replacement

fluid

enables

use

of

an

elevated

convection

fluid

rate

especially

in

predilution

mode

and

facilitates

a

dialysis

dose

increase

without

a

cost

increase

The

use

of

ultrapure

dialysate

i.e.

sterile

and

pyrogen

free

as

used

for

on-line

HDF

dialysate

should

reduce

the

diseases

possibly

associated

with

chronic

inflammation

related

to

contaminated

dialysate

-LSB-

-RSB-

e.g.

β2

microglobulin

amyloidosis

hypercatabolism

with

loss

of

lean

body

mass

decreased

growth

rate

fibrosis

and

cardiovascular

diseases

A

high

flux

membrane

-LSB-

-RSB-

with

an

elevated

ultrafiltration

coefficient

of

permeability

enabling

backfiltration

from

the

dialysate

to

the

blood

compartment

which

is

called

retrofiltration

increases

these

risks

especially

with

contaminated

dialysate

-LSB-

-RSB-

Guideline

extracorporeal

blood

access

and

circulation

fistula

vascular

access

is

preferred

for

long-term

chronic

hemodialysis

in

young

children

less

than

kg

the

time

needed

to

develop

a

fistula

before

it

can

be

used

could

be

some

months

the

double-needle

technique

is

the

standard

but

single

needle

with

double

pump

system

is

an

alternative

a

single

lumen

catheter

with

clamps

offers

for

small

children

an

acceptable

compromise

between

a

very

low

extracorporeal

blood

volume

and

valuable

dialytic

efficacy

total

extracorporeal

blood

volume

-LRB-

needles

tubing

and

dialyzer

-RRB-

should

approximately

be

less

than

of

patient

total

blood

volume

anticoagulation

in

the

extracorporeal

circuit

is

achieved

either

with

conventional

heparin

or

with

low-molecular-weight

heparin

an

extracorporeal

blood

flow

rate

-LRB-

QB

-RRB-

of

mL

min

m

or

mL

min

kg

is

often

sufficient

The

success

of

chronic

hemodialysis

depends

on

good

vascular

access

internal

arteriovenous

fistulae

-LRB-

AVF

-RRB-

shunt

-LRB-

AVS

-RRB-

graft

-LRB-

AVG

-RRB-

or

central

venous

catheter

The

type

of

access

used

is

variable

depending

on

factors

in

different

units

and

countries

for

example

surgical

experience

patient

age

and

size

the

time

available

before

dialysis

must

be

started

and

the

presumed

waiting

time

before

transplantation

Patient

choice

plays

a

major

part

especially

with

adolescents

A

catheter

is

more

commonly

used

in

the

USA

than

in

Europe

-LSB-

-RSB-

A

catheter

can

be

a

primary

access

particularly

in

acute

renal

failure

or

chronic

renal

failure

with

acute

presentation

in

small

children

and

in

the

case

of

a

presumed

short

period

on

chronic

hemodialysis

Internal

jugular

vein

catheter

access

is

superior

to

subclavian

vein

it

admittedly

preserves

the

future

arteriovenous

fistula

implantation

on

the

arm

Femoral

catheter

access

should

be

used

only

for

rescue

and

transient

access

if

intensive

care

is

needed

it

is

easy

to

perform

but

with

a

higher

risk

of

infection

and

thrombosis

A

double

lumen

cuffed

catheter

at

least

French

is

mostly

preferred

for

children

and

has

been

reported

to

have

a

survival

rate

as

high

as

to

in

one

year

-LSB-

-RSB-

or

as

low

as

-LSB-

-RSB-

Nevertheless

in

small

infants

a

single

lumen

catheter

used

with

the

alternative

clamps

technique

offers

an

acceptable

compromise

between

recirculation

and

both

the

amount

of

extracorporeal

blood

volume

and

the

achieved

blood

flow

-LSB-

-RSB-

Thrombosis

a

major

cause

of

catheter

failure

is

reported

to

be

between

and

-LSB-

-RSB-

Thrombosis

causing

poor

flow

can

be

corrected

to

salvage

the

catheter

by

different

methods

catheter

replacement

over

guidewire

systemic

oral

anticoagulation

and

local

urokinase

or

tissue

plasminogen

activator

instillation

-LSB-

-RSB-

Loss

of

catheter

access

related

to

infection

has

decreased

during

the

last

decade

the

aggressive

use

of

antibiotics

and

perhaps

antibiotic

lock

therapy

although

not

universally

accepted

account

for

this

lower

rate

of

infection

related

catheter

loss

-LSB-

-RSB-

Microsurgery

enables

creation

of

a

functional

AVF

at

the

wrist

in

most

children

even

small

ones

-LSB-

-RSB-

but

only

a

few

surgeons

are

trained

for

vascular

microsurgery

which

therefore

is

rarely

used

Creation

of

a

fistula

at

the

elbow

is

a

second-choice

vascular

access

With

a

non

functional

cephalic

vein

a

basilic

vein

transposition

i.e.

superficialization

is

possible

-LSB-

-RSB-

Synthetic

grafts

should

be

reserved

for

children

who

have

exhausted

autologous

veins

and

should

be

used

in

children

only

very

rarely

For

all

these

reasons

preoperative

evaluation

of

the

vessels

to

determine

the

correct

choice

of

vein

before

the

operation

is

mandatory

The

non-dominant

arm

should

be

regarded

as

first

choice

of

fistula

implantation

The

survival

rate

for

a

AVF

is

higher

than

the

survival

rate

for

a

catheter

with

more

than

two

thirds

of

the

children

having

a

functioning

AVF

at

four

years

-LSB-

-RSB-

With

a

basilic

vein

superficialization

the

fistula

should

not

be

used

before

full

healing

-LRB-

to

weeks

-RRB-

to

avoid

a

dissecting

hematoma

Otherwise

the

time

needed

for

venous

development

before

use

depends

on

the

age

of

the

patient

and

the

place

of

the

AVF

-LRB-

distal

or

proximal

-RRB-

In

small

children

this

period

of

time

is

often

a

delay

of

months

Before

surgery

it

is

essential

to

avoid

venopuncture

of

the

selected

arm

in

the

weeks

before

AVF

creation

It

is

of

interest

to

protect

the

dominant

arm

from

the

beginning

of

taking

care

of

a

child

with

chronic

dialysis

risk

to

enable

if

necessary

implantation

of

a

fistula

Such

venoprotection

should

not

be

forgotten

for

peritoneal

dialysis

children

even

babies/infants

For

a

period

of

time

before

surgery

especially

for

small

children

-LSB-

-RSB-

dilatation

of

the

veins

by

immersion

of

the

forearm

in

hot

water

is

advantageous

a

maneuver

enhanced

by

placement

of

a

tourniquet

A

proximal

AVF

with

a

high

blood

flow

usually

close

to

mL

min

m

is

a

risk

factor

for

cardiac

failure

Nevertheless

the

major

complication

is

thrombosis

consequent

to

local

stenosis

Therefore

follow

up

of

the

access

flow

is

essential

on

the

one

hand

clinically

auscultation

-LRB-

the

sound

of

the

AVF

is

maximum

at

the

surgical

site

and

decreases

with

distance

from

the

fistulae

-RRB-

observation

-LRB-

elevation

of

the

forearm

should

induce

emptying

of

the

previous

dilated

veins

and

on

the

other

hand

by

Doppler

ultrasound

or

vascular

access

flow

monitoring

-LSB-

-RSB-

Application

of

regular

access

flow

monitoring

can

be

used

to

detect

vascular

stenosis

before

complete

AVF

thrombosis

-LSB-

-RSB-

But

it

should

be

remembered

that

Transonic

access

flow

monitoring

can

only

be

performed

with

double-pump

dialysis

and

is

not

available

for

pediatric-sized

blood

lines

The

extracorporeal

blood

flow

rate

is

achieved

through

venous

puncture

most

often

via

two

needles

one

for

blood

aspiration

called

the

arterial

needle

one

for

venous

reinjection

called

the

venous

needle

The

distance

between

the

needles

should

be

sufficient

to

limit

recirculation

which

is

best

prevented

by

opposite

orientation

of

the

needles

the

arterial

one

toward

the

fistula

the

venous

one

in

the

opposite

direction

Usually

the

needle

size

is

at

initiation

of

dialysis

thereafter

considering

patient

need

and

fistula

development

or

needles

particularly

in

adolescents

can

be

used

to

achieve

a

sufficiently

high

blood

flow

rate

Pain

related

to

the

puncture

should

be

prevented

by

anesthetic

cream

-LRB-

Emla

or

Amelop

-RRB-

this

advance

is

important

for

both

the

children

and

nurses

-LSB-

-RSB-

An

extracorporeal

blood

flow

rate

-LRB-

QB

-RRB-

of

mL

min

m

mL

min

kg

is

often

sufficient

to

achieve

the

targeted

goals

with

double

needle

dialysis

in

small

children

QB

is

determined

using

body

weight

-LRB-

BW

kg

-RRB-

-LRB-

BW

-RRB-

QB

-LRB-

mL

min

-RRB-

The

arterial

blood

aspiration

pressure

should

be

monitored

if

possible

and

kept

between

mmHg

to

limit

endothelial

trauma

For

single-needle

dialysis

in

children

the

highest

blood

flow

rate

is

obtained

with

a

double

pump

system

-LRB-

venous

flow

higher

than

arterial

flow

-RRB-

monitored

by

the

pressure

system

called

time

pressure

regulation

The

risk

of

recirculation

is

important

with

the

latter

some

machines

limit

this

risk

more

than

others

especially

with

the

addition

of

clamps

Conversely

for

small

infants

a

single

lumen

catheter

used

with

the

alternative

clamps

technique

is

an

acceptable

compromise

between

recirculation

and

both

the

extracorporeal

blood

volume

and

the

achieved

blood

flow

-LSB-

-RSB-

The

total

extracorporeal

blood

volume

-LRB-

needles

tubing

and

dialyzer

-RRB-

should

preferably

be

less

than

of

patient

total

blood

volume

This

is

essential

for

small

children

however

the

relative

normal

hemoglobin

level

obtained

with

erythropoïetin

therapy

enables

this

volume

to

be

exceeded

slightly

without

significant

hypotension

at

the

end

of

dialysis

session

when

the

patient

reaches

dry

body

weight

Nevertheless

it

should

be

kept

in

mind

that

the

higher

the

extracorporeal

blood

volume

the

higher

the

volume

of

returned

fluid

which

will

load

the

patient

with

fluid

at

the

end

of

the

dialysis

session

-LRB-

In

very

small

children

the

substitution

by

air

may

be

necessary

to

limit

blood

loss

on

one

side

and

high

substitution

volume

on

the

other

side

but

is

very

dangerous

and

should

be

strictly

monitored

-RRB-

System

priming

with

saline

albumin

and

sometimes

blood

should

be

applied

in

the

first

dialysis

sessions

with

babies

or

small

infants

Anticoagulation

of

the

extracorporeal

blood

volume

is

performed

either

by

use

of

conventional

heparin

with

continuous

infusion

of

to

IU

kg

h

or

with

low-molecular-weight

heparin

at

mg

kg

as

a

bolus

at

the

beginning

of

the

dialysis

session

If

the

hematocrit

is

over

the

risk

of

clotting

is

increased

Regional

citrate

anticoagulation

is

sometimes

used

especially

when

acute

dialysis

is

needed

-LSB-

-RSB-

Predilution

treatment

feasible

in

either

hemofiltration

or

hemodiafiltration

reduces

the

risk

of

clotting

and

even

enables

dialysis

without

anticoagulation

in

some

circumstances

In

the

presence

of

thrombopenia

heparin-toxicity

is

to

be

suspected

The

venous

blood

line

has

a

pediatric

size

air-trap

chamber

to

limit

extracorporeal

blood

volume

The

dialysis

membrane

is

protected

by

an

arterial

chamber

of

expansion

which

in

small

children

is

often

not

incorporated

in

the

line

to

reduce

the

extracorporeal

blood

volume

Prevention

or

treatment

of

ethylene

oxide

allergy

is

possible

by

using

steam

sterilization

of

needles

lines

and

membranes

this

is

becoming

the

preferred

option

throughout

Europe

Guideline

which

dialyzer

membrane

to

choose

synthetic

membrane

low

flux

capillary

configuration

high-flux

membrane

use

requires

use

of

ultrapure

dialysate

removal

of

urea

and

other

uremic

toxins

dialytic

should

be

considered

especially

in

chronic

long-term

dialysis

Three

general

types

of

membrane

are

available

at

present

-LSB-

-RSB-

unmodified

cellulose

-LRB-

low

flux

and

so-called

bioincompatible

membranes

-RRB-

modified/regenerated

cellulose

-LRB-

low

flux

or

high

flux

so-called

relatively

biocompatible

-RRB-

synthetic

-LRB-

low

flux

or

high

flux

so

called

relatively

biocompatible

-RRB-

The

choice

of

a

dialyzer

membrane

should

take

into

account

the

following

-LRB-

Table

-RRB-

Table

Dialyzer

membranes

practical

parameters

of

choice

Type

of

membrane

biocompatibility

toward

complement

system

Initial

blood

volume

needed

i.e.

area-related

quality

of

restitution

Molecular

permeability

maximum

clearance

for

urea

and

the

other

uremic

toxins

e.g.

phosphate

related

to

potential

patient

osmotic

risk

Hydraulic

permeability

possibility

of

use

for

HF

or

HDF

procedure

but

related

to

back

filtration

risk

high

flux

membranes

need

ultrapure

dialysate

Adsorption

capacity

on

to

the

membrane

-LRB-

a

characteristic

of

synthetic

membranes

-RRB-

Costthe

biocompatibility

of

the

material

towards

leucocytes

and

complement

activationthe

blood

volume

priming

requirement

which

is

membrane

area-relatedthe

permeability

determined

in

the

most

simple

way

by

two

characteristics

hydraulic

permeability

-LRB-

CUF

-RRB-

measured

in

mL

per

mmHg

of

transmembrane

pressure

achieved

per

hour

i.e.

either

low

permeability

CUF

under

mL

mmHg

h

-LRB-

low-flux

membrane

-RRB-

and

high

permeability

CUF

over

to

mL

mmHg

h

-LRB-

high-flux

membrane

-RRB-

molecular

permeability

determined

at

least

by

the

molecular

weight

of

the

molecule

considered

usually

between

and

for

urea

and

lower

for

the

other

uremic

toxins

with

a

cut

off

of

zero

for

albumin

In

practice

this

cut

off

is

often

under

a

molecular

weight

of

Daltons

The

profile

of

this

molecular

permeability

-LSB-

-RSB-

is

a

specific

characteristic

of

each

manufactured

dialysis

membrane

Highly

permeable

membranes

give

the

theoretical

potential

for

middle-molecular-weight

-LRB-

Babb

theory

to

Daltons

-RRB-

uremic

toxins

being

removed

during

dialysis

In

adult

dialysis

patients

the

clinical

benefits

of

improved

removal

of

middle

molecules

by

high

flux

large

pore

biocompatible

membranes

more

or

less

established

are

-LSB-

-RSB-

reduction

of

uremia

related

amyloidosis

maintenance

or

residual

renal

function

and

reduction

of

inflammation

malnutrition

anemia

dyslipidemia

and

mortality.The

absorption

capacity

on

to

the

membrane

-LRB-

TNF

β2

microglobulin

-RRB-

a

characteristic

of

synthetic

membranes

For

conventional

dialysis

low-flux

membranes

are

suitable

but

to

achieve

hemofiltration

or

hemodiafiltration

high-flux

membranes

are

necessary

The

higher

the

hydraulic

permeability

the

higher

is

the

backfiltration

risk

this

process

could

be

limited

both

by

permanent

convective

flow

from

the

blood

compartment

to

the

dialysate

compartment

as

ultrafiltration

-LRB-

HF

HDF

or

at

least

weight

loss

-RRB-

and

by

use

of

ultrapure

dialysate

Synthetic

membranes

seem

the

best

theoretical

choice

but

clinical

justification

of

the

relatively

higher

cost

is

uncertain

-LSB-

-RSB-

Justification

for

use

of

high-flux

synthetic

membranes

as

used

in

on-line

HDF

remains

a

matter

of

debate

for

children

on

dialysis

for

short

periods

only

while

waiting

for

their

kidney

transplant.Reuse

of

the

membrane

is

not

applied

in

practice

for

children

Guideline

the

dialysate

bicarbonate

buffered

low

calcium

level

-LRB-

mmol

L

-RRB-

becomes

the

standard

glucose

concentration

at

physiological

level

dialysate

quality

control

-LRB-

germs

and

endotoxins

-RRB-

is

required

The

dialysate

is

prepared

as

a

dilution

of

concentrate

with

water

ideally

with

ultrapure

water

The

composition

of

the

dialysate

has

changed

over

the

last

two

decades

-LSB-

-RSB-

Acetate

as

buffer

has

been

replaced

by

bicarbonate

with

the

development

of

machines

with

two

separate

dilution

pumps

one

for

bicarbonate

concentrate

free

from

calcium

often

as

a

powder

and

one

for

the

acid

concentrate

containing

residual

levels

of

acetate

and

the

electrolytes

-LRB-

K

Cl

Ca

-RRB-

The

current

use

of

oral

calcium

carbonate

as

a

phosphate

binder

has

mandated

the

need

to

decrease

the

calcium

concentration

of

the

dialysate

usually

at

a

low

rate

mmol

L

less

often

at

a

normal

rate

mmol

L

avoiding

the

historically

high

level

of

mmol

L

In

fact

the

use

of

calcium

carbonate

combined

with

a

high

concentration

of

calcium

in

the

dialysate

often

led

to

an

elevated

Ca

P

serum

product

compared

with

the

current

recommendation

of

a

product

less

than

m

-LRB-

dL

-RRB-

-LSB-

-RSB-

This

Ca

P

serum

product

seems

to

be

an

important

factor

implicated

in

the

vascular

calcifications

seen

in

the

dialyzed

patients

-LSB-

-RSB-

affecting

even

the

dialyzed

children

-LSB-

-RSB-

The

need

for

glucose

in

the

dialysate

is

of

importance

-LSB-

-RSB-

and

should

be

near

the

physiological

concentration

Higher

glucose

concentrations

or

the

introduction

of

parenteral

feeding

during

dialysis

will

drive

the

potassium

into

the

cells

leading

to

ineffective

potassium-extraction

-LSB-

-RSB-

Potassium-free

dialysate

is

rarely

used

because

of

the

theoretical

risk

of

hypokalemia

-LSB-

-RSB-

Therefore

low

-LRB-

mmol

L

-RRB-

normal

-LRB-

mmol

L

-RRB-

and

high

-LRB-

mmol

L

-RRB-

potassium

dialysate

are

available

enabling

individual

adaptation

and

prevention

of

the

arythmogenic

potential

of

dialysis

-LSB-

-RSB-

Nevertheless

special

attention

should

be

devoted

to

avoiding

any

confusion

among

the

potassium

charged

dialysates

Sodium

concentrations

have

increased

from

the

previous

classical

level

of

mmol

L

to

a

more

physiological

level

of

to

mmol

L

Newer

machine

capabilities

enable

dialysate

profiles

to

change

during

a

dialysis

with

respect

to

sodium

and

ultrafiltrate

profiles

-LSB-

-RSB-

to

increase

tolerated

weight

loss

and

bicarbonate

profiles

-LSB-

-RSB-

to

enhance

phosphate

removal

Intermittent

ultrafiltration

rates

enabling

better

plasma

refilling

is

the

most

common

profile

used

Similarly

the

dialysate

flow

rate

can

be

adapted

to

need

usually

in

the

range

to

mL

min

In

general

practice

mL

min

is

used

The

dialysate

flow

is

usually

in

the

opposite

direction

of

the

blood

flow

separated

by

the

membrane

of

the

dialyzer

Dialytic

thermal

exchanges

seem

of

importance

especially

for

babies

and/or

high-flow

dialysate

use

leading

to

a

risk

of

patient

hypothermia

Control

of

thermal

exchanges

during

a

dialysis

session

is

therefore

available

on

a

new

machine

-LSB-

-RSB-

Guideline

post-dialytic

dry

weight

assessment

and

adjustment

particularly

difficult

to

define

in

growing

children

no

unique

optimum

method

importance

of

a

clinical

pediatric

experience

need

for

regular

assessment

in

a

growing

child

close

collaboration

with

pediatric

renal

dietician

Patient

dry

weight

is

defined

as

the

weight

at

the

termination

of

a

regular

dialysis

session

below

which

the

patient

will

become

symptomatically

hypotensive

Incorrect

estimation

of

dry

weight

will

lead

either

to

chronic

fluid

overload

or

chronic

dehydration

Estimation

of

dry

weight

is

particularly

difficult

in

children

for

many

reasons

First

the

hypotensive

tendency

during

a

dialysis

session

is

multifactorial

and

not

only

related

to

the

ultrafiltration

rate

but

also

to

the

plasma

refilling

rate

capacity

-LSB-

-RSB-

Second

body

composition

i.e.

total

body

water

ratio

to

total

body

mass

is

variable

with

age

especially

during

infancy

and

puberty

In

infants

and

in

adolescents

dry

weight

must

be

assessed

almost

monthly

to

follow

rapid

body

composition

changes

during

a

rapid

growth

period

This

is

also

important

under

anabolic

conditions

such

as

with

growth

hormone

treatment

and

conversely

under

catabolic

conditions

such

as

the

ill

child

with

intercurrent

infections

or

reduced

food

intake

Clinical

criteria

used

to

assess

hydration

status

are

important

but

not

always

reliable

Therefore

different

approaches

have

been

proposed

assessment

of

total

body

water

by

bioelectrical

impedance

analysis

-LSB-

-RSB-

continuous

measurement

of

hematocrit

variations

by

non-invasive

methods

during

dialysis

-LSB-

-RSB-

plasma

atrial

natriuretic

peptide

or

cyclic

guanosine

monophosphate

determination

-LSB-

-RSB-

and

last

by

echography

of

the

inferior

vena

cava

-LRB-

IVC

-RRB-

-LSB-

-RSB-

Measurement

of

the

diameter

of

the

IVC

-LRB-

IVCD

-RRB-

by

ultrasound

expressed

as

an

index

to

body

surface-area

in

mm

m

and

the

decrease

on

deep

inspiration

called

the

collapse

index

expressed

as

a

percentage

-LRB-

-RRB-

seems

to

be

an

accurate

non-invasive

method

easily

performed

serially

An

IVCD

between

and

mm

m

and

a

collapse

index

between

and

is

considered

as

representing

normovolemia

-LSB-

-RSB-

However

unlike

body

impedance

interstitial

volume

and

sodium

balance

are

not

reflected

by

IVCD

-LSB-

-RSB-

In

fact

all

these

approaches

have

to

be

balanced

by

clinical

judgment

and

experience

and

combined

with

nutritional

support

Achievement

of

dry

weight

during

ultrafiltration

is

associated

with

a

drop

of

the

hematocrite

level

Ultrafiltration

is

well

tolerated

until

a

certain

level

of

decrease

of

initial

hematocrite

called

crash

hematocrite

a

patient

individual

characteristic

usually

over

blood

volume

reduction

over

a

session

-LSB-

-RSB-

If

the

hematocrite

curve

is

flat

over

time

during

a

dialysis

session

the

patient

could

be

considered

as

being

over

his

optimum

dry

weight

-LSB-

-RSB-

In

practice

monitoring

of

hematocrit

-LRB-

or

blood

volume

-RRB-

and

guided

ultrafiltration

should

avoid

both

fluid

overload

and

hypotensive

crash

hematocrit

and

consequently

approach

more

precisely

the

patient

dry

weight

-LSB-

-RSB-

Guideline

urea

dialytic

kinetic

dialysis

dose

and

protein

intake

assessment

-LRB-

nutrition

-RRB-

Urea

kinetic

modeling

-LRB-

UKM

-RRB-

has

been

widely

accepted

as

a

method

for

dialysis

dose

assessment

despite

its

limited

value

as

a

unique

measure

of

dialysis

adequacy

Does

small

solute

clearance

really

matter

-LSB-

-RSB-

In

adult

patients

the

HEMO

study

suggested

that

increasing

urea

clearance

above

currently

accepted

target

ranges

does

not

lead

to

improved

patient

outcome

-LSB-

-RSB-

Although

urea

per

se

is

not

toxic

in

concentrations

normally

encountered

in

dialysis

patients

it

may

serve

as

a

marker

of

unknown

toxins

of

uremia

some

of

which

are

called

middle-molecular-weight

uremic

toxins

-LSB-

-RSB-

UKM

facilitates

identification

of

underdialyzed

patients

and

recognition

of

dietary

compliance

The

measures

most

widely

used

to

gauge

dialyzer

treatment

are

Kt/V

that

is

dialyzer

urea

clearance

-LRB-

K

-RRB-

multiplied

by

duration

-LRB-

t

-RRB-

of

the

dialysis

session

and

divided

by

urea

volume

-LRB-

V

-RRB-

of

distribution

and

the

normalized

protein

catabolic

rate

-LRB-

nPCR

-RRB-

-LSB-

-RSB-

Urea

dialytic

reduction

rate

-LRB-

URR

-RRB-

is

derived

from

the

pre

and

post-dialysis

serum

urea

values

and

quantitates

urea

removal

by

dialysis

URR

expressed

as

the

ratio

post/pre

should

be

at

least

equal

to

or

lower

than

and

when

expressed

as

the

difference

between

pre

and

post-urea

divided

by

the

predialysis

value

should

at

least

equal

to

or

higher

than

-LSB-

-RSB-

URR

is

proportional

to

dialysis

efficiency

and

thus

to

urea

dialytic

clearance

URR

is

inversely

proportional

to

the

urea

refilling

rate

of

the

blood

compartment

and

the

extracellular

space

-LRB-

EC

-RRB-

from

the

intracellular

space

-LRB-

IC

-RRB-

called

the

transcellular

urea

mass

transfer

coefficient

-LRB-

Kie

-RRB-

URR

is

also

correlated

with

the

amount

of

urea

dialytic

removal

-LRB-

Kt

-RRB-

compared

to

the

amount

of

urea

body

content

-LRB-

V

-RRB-

and

thus

to

Kt/V

Usually

urea

dialytic

clearance

in

children

is

low

in

comparison

with

the

high

Kie

which

is

between

to

mL

min

-LRB-

to

mL

min

kg

BW

-RRB-

-LSB-

-RSB-

Nevertheless

after

dialysis

the

concentration

of

urea

in

plasma

increases

rapidly

in

an

initial

period

usually

until

min

postdialysis

-LSB-

-RSB-

This

postdialytic

urea

rebound

-LRB-

PDUR

-RRB-

is

a

multifactorial

event

-LSB-

-RSB-

Vascular

access

and

cardiopulmonary

recirculation

occurs

within

the

first

to

min

of

discontinuing

hemodialysis

and

account

for

to

of

total

PDUR

Subsequently

tissue

rebound

occurs

because

of

intercompartmental

i.e.

IC

versus

EC

urea

dysequilibrium

at

the

end

of

the

dialysis

session

and

tissue

re-equilibration

which

is

usually

complete

within

one

hour

postdialysis

reaching

the

equilibrated

postdialytic

plasma

urea

concentration

For

highly

diffusible

substances

such

as

urea

distribution

in

total

body

water

-LRB-

TBW

-RRB-

seems

to

be

limited

by

cardiovascular

flow

rather

than

diffusion

-LSB-

-RSB-

The

apparent

IC

EC

two-pool

model

should

perhaps

be

the

result

of

a

regional

blood

flow

distribution

system

in

which

approximately

of

TBW

-LRB-

and

thereby

urea

-RRB-

is

located

in

muscle

bone

and

skin

with

organs

receiving

only

to

of

the

cardiac

output

i.e.

low-flow

system

The

remaining

organs

contain

only

of

TBW

-LRB-

hence

urea

-RRB-

but

receive

of

the

cardiac

output

high-flow

system

One

would

expect

the

urea

concentration

in

these

organs

to

fall

quite

rapidly

during

dialysis

This

flow

system

and

the

vascular

resistance

model

could

explain

the

great

variability

of

the

PDUR

among

patients

for

which

the

IC

EC

two-pool

model

is

not

accurate

Do

some

patients

have

thicker

cell

walls

than

others

By

contrast

the

possible

causes

of

vascular

resistance

variability

i.e.

hypovolemia

hypertension

heart

failure

hematocrit

alkalosis

or

acidosis

low-temperature

dialysate

can

explain

PDUR

variability

The

URR

variability

could

also

be

explained

by

vascular

resistance

changes

over

the

dialysis

session

at

least

for

urea

-LSB-

-RSB-

Kt/V

calculation

based

on

a

single

pool

urea

model

neglects

compartmental

urea

distribution

in

the

body

hence

PDUR

resulting

in

overestimation

of

actual

Kt/V

Therefore

a

two

pool

model

should

be

applied

using

instead

of

the

urea

plasma

concentration

at

the

end

of

the

dialysis

the

equilibrated

urea

i.e.

min

postdialysis

-LSB-

-RSB-

Other

improvements

from

the

initial

formula

are

proposed

to

provide

a

more

accurate

Kt/V

calculation

weight

loss

-LRB-

UF/BW

-RRB-

and

urea

generation

during

the

dialysis

session

-LRB-

td

-RRB-

leading

to

the

Daugirdas

and

Schwartz

formula

proposed

in

-LSB-

-RSB-

where

td

is

the

dialysis

time

-LRB-

h

-RRB-

Cpre

and

Ceq

are

respectively

the

predialysis

and

equilibrated

postdialysis

urea

concentrations

and

UF/BW

is

the

ultrafiltrate-to-body

weight

ratio

-LRB-

L

kg

-RRB-

The

predialysis

blood

sample

should

be

taken

from

the

arterial

line

before

any

rinsing

Because

of

the

practical

difficulty

in

obtaining

the

postdialysis

equilibrated

urea

sample

min

after

the

end

of

the

dialysis

different

indices

have

been

proposed

to

estimate

Ceq

for

example

using

a

min

-LSB-

-RSB-

or

a

min

-LSB-

-RSB-

post

treatment

sample

The

most

important

rule

of

the

urea

end

dialysis

sample

should

be

the

use

of

the

stop

dialysate

flow

method

-LSB-

-RSB-

measuring

urea

min

after

angio

access

was

removed

and

cardiopulmonary

recirculation

completed

The

other

major

cause

of

error

for

the

Kt/V

calculation

is

determination

of

V

The

V

hence

the

TBW

could

be

calculated

from

a

formula

-LRB-

Table

-RRB-

-LSB-

-RSB-

or

determined

by

bioimpedance

measurements

-LSB-

-RSB-

Table

Formulas

enabling

calculation

of

the

volume

of

distribution

of

urea

in

liters

-LRB-

total

body

water

-RRB-

using

height

weight

sex

and

age

-LRB-

from

Ref

-LSB-

-RSB-

-RRB-

Boys

Ht

cmV

BW

-LRB-

kg

-RRB-

ht

-LRB-

cm

-RRB-

Ht

cmV

BW

-LRB-

kg

-RRB-

ht

-LRB-

cm

-RRB-

Girls

Ht

cmV

BW

-LRB-

kg

-RRB-

ht

-LRB-

cm

-RRB-

Ht

cmV

BW

-LRB-

kg

-RRB-

ht

-LRB-

cm

-RRB-

Guideline

dialysis

dose

and

outcome

only

small

solute

urea

clearance

prescription

a

minimum

Kt/V

urea

level

of

is

thought

to

be

desirable

adequacy

tests

should

be

performed

monthly

dialysis

and

residual

renal

small-solute

clearance

are

not

equivalent

dialysis

prescription

should

be

adequate

before

being

optimum

not

only

a

urea

dialysis

dose

Although

the

optimum

level

of

Kt/V

required

is

matter

of

debate

a

minimum

Kt/V

level

of

is

now

thought

to

be

desirable

-LSB-

-RSB-

Overall

this

Kt/V

as

an

index

of

dialysis

dose

should

only

be

analyzed

in

comparison

with

the

nPCR

hence

the

diet

protein

and

caloric

intake

-LRB-

Fig.

-RRB-

Because

of

the

mathematical

relationship

between

Kt/V

and

nPCR

-LSB-

-RSB-

the

real

impact

of

these

variables

for

a

given

patient

would

determine

the

therapy

necessary

for

a

patient

to

achieve

an

urea

dialysis

dose

Nevertheless

increasing

dialysis

dose

seems

to

have

a

direct

impact

on

nutrition

-LSB-

-RSB-

and

the

combination

of

increased

dialysis

dose

and

adequate

nutrition

can

promote

normal

growth

in

children

treated

with

long-term

hemodialysis

-LSB-

-RSB-

Therefore

malnutrition

should

be

avoided

-LSB-

-RSB-

by

using

a

diet

survey

anthropometric

measurements

and

perhaps

determination

-LSB-

-RSB-

Fig.

Dialysis

prescription

balance

Does

small

solute

clearance

i.e.

urea

really

matter

-LSB-

-RSB-

Because

of

the

limited

number

of

children

on

chronic

dialysis

the

relationship

between

optimum

urea

dialysis

dose

and

patient

outcome

will

be

difficult

to

establish

It

is

however

known

that

blood

purification

dialysis

and

residual

renal

small

solute

clearance

are

not

equivalent

-LSB-

-RSB-

giving

more

importance

to

other

uremic

toxins

whose

removal

is

enhanced

using

high-flux

dialyzer

membranes

with

on-line

hemodiafiltration

-LSB-

-RSB-

Even

if

the

pediatric

data

only

seem

to

be

unique

center

experiences

the

case

for

a

greater

urea

dialysis

dose

-LSB-

-RSB-

could

be

correlated

with

both

growth

rate

enhancement

-LSB-

-RSB-

and

improved

cardiac

function

-LSB-

-RSB-

The

duration

of

each

hemodialysis

session

is

also

matter

of

debate

long

duration

being

able

to

induce

regression

of

left

ventricular

hypertrophy

in

adult

patients

-LSB-

-RSB-

and

being

able

in

children

-LSB-

-RSB-

to

promote

growth

and

well

being

In

the

same

way

daily

dialysis

seems

related

to

better

clinical

results

both

in

adults

-LSB-

-RSB-

and

in

adolescents

-LSB-

-RSB-

Dialysis

prescription

should

be

adequate

before

being

optimum

-LRB-

Table

-RRB-

-LSB-

-RSB-

In

long

term

chronic

dialyzed

children

the

individualized

prescription

should

consider

all

the

available

new

strategies

to

fully

preserve

at

the

best

the

life

chances

-LSB-

-RSB-

Table

Hemodialysis

prescription

for

children

adequate

before

optimum

Dialysis

modality

should

enable

achievement

of

blood

pressure

control

-LRB-

without

antihypertensive

medications

for

most

children

-RRB-

normal

myocardial

morphology

and

function

Dialysis

dose

prescription

should

not

only

be

an

urea

dialysis

dose

Removal

of

the

other

uremic

toxins

should

be

considered

not

only

middle

molecules

but

overall

phosphate

Dialysis

frequency

and

duration

must

be

adjusted

to

the

tolerance

of

ultrafiltration

to

reach

the

dry

weight

Ultrafiltration

rate

should

not

exceed

of

body

weight

per

hour

-LRB-

in

theory

no

more

than

BW

loss

per

whole

session

-RRB-

Blood

volume

-LRB-

hematocrite

-RRB-

guided

ultrafiltration

secure

A

regular

diet

survey

is

essential

to

maintain

adequate

protein

and

calorie

intakes

Urea

kinetic

assessment

enables

not

only

urea

dialysis

dose

calculation

i.e.

Kt/V

but

also

estimation

of

protein

intake

by

use

of

the

PCRn

calculation

-LRB-

protein

catabolic

rate

-RRB-

Fasting

to

enable

a

short

duration

three

times

a

week

dialysis

schedule

is

inadequate

care

management

Too

fast

ultrafiltration

can

induce

hypotension

and

cramps

during

dialysis

usually

during

the

second

half

time

session

and

fatigue

and/or

hang

over

after

dialysis

A

small

solute

e.g.

urea

clearance

which

is

too

high

is

a

factor

of

disequilibrium

syndrome

occurring

during

dialysis

usually

after

the

first

half/or

one

hour

session

time

with

headache

even

seizures

nausea

vomiting

sleepiness

or

a

hypertensive

tendency

with

a

narrow

range

between

systolic

and

diastolic

pressure

values

Symptoms

usually

disappear

a

few

hours

after

the

end

of

the

dialysis

Guideline

the

dialysis

session

prescription

and

monitoring

individual

prescription

is

required

babies/infants/children

specificities

assessment

and

adjustment

is

needed

regularly

in

small/growing

children

psychological

preparation

of

the

child

and

his

family

is

needed

pain

prevention

is

essential

The

first

dialysis

session

is

of

importance

to

induce

child

and

parent

confidence

therefore

appropriate

preparation

is

needed

The

site

of

the

puncture

of

the

fistula

most

often

with

a

double

needle

size

gauge

is

carefully

chosen

and

determined

so

that

the

needles

are

sufficiently

separated

to

limit

recirculation

Pain

prevention

is

essential

by

application

of

a

xylocaine

ointment

-LRB-

Emla

-RRB-

one

hour

before

needle

insertion

-LSB-

-RSB-

Psychological

preparation

of

the

child

and

family

is

also

needed

to

limit

anxious

stress

-LSB-

-RSB-

An

aseptic

procedure

is

essential

The

extracorporeal

circulation

is

adapted

to

the

level

of

arterial

aspiration

pressure

if

measurable

by

the

machine

to

prevent

endothelial

vascular

trauma

-LRB-

not

less

than

mmHg

-RRB-

The

venous

return

pressure

should

not

be

more

than

mmHg

to

prevent

endothelial

vascular

trauma

During

the

first

dialysis

session

the

blood

flow

rate

is

maintained

at

a

low

level

to

prevent

the

dysequilibrium

syndrome

secondary

to

too

efficient

solute

removal

during

this

first

session

Therefore

the

blood

flow

rate

should

be

approximately

mL

kg

BW

-LRB-

or

mL

m

-RRB-

or

even

less

so

that

urea

clearance

will

be

less

than

mL

min

kg

BW

which

is

usually

well

tolerated

even

in

small

children

and

limits

the

development

of

the

dysequilibrium

syndrome

The

duration

of

the

first

dialysis

session

should

be

short

no

more

than

h

or

adapted

to

the

ultrafiltration

need

The

dysequilibrium

syndrome

is

most

often

only

symptomatic

after

one

to

two

hours

of

dialysis

with

variable

symptoms

such

as

headache

or

seizure

vomiting

fatigue

sleepiness

or

a

hypertensive

tendency

with

a

narrow

range

between

systolic

and

diastolic

pressure

values

If

needed

mannitol

infusion

-LRB-

g

kg

BW

over

to

h

during

dialysis

-RRB-

is

effective

in

preventing

the

syndrome

Symptoms

usually

disappear

a

few

hours

after

the

end

of

the

dialysis

The

extracorporeal

blood

flow

rate

the

duration

of

the

session

and

the

number

of

sessions

a

week

is

progressively

increased

to

individual

patient

need

Usually

a

blood

flow

rate

of

to

mL

min

m

and

three

sessions

per

week

for

to

h

per

session

achieve

the

minimum

target

prescription

of

to

Kt/V

-LSB-

-RSB-

The

duration

of

a

dialysis

session

is

often

prescribed

to

reach

the

anticipated

dry

weight

at

the

end

of

the

session

The

total

amount

and

the

rate

of

ultrafiltration

needed

must

be

tolerable

A

weight

loss

per

hour

of

to

of

the

BW

is

standard

-LSB-

-RSB-

and

most

often

well

tolerated

Intermittent

ultrafiltration

with

bicarbonate

buffered

dialysate

which

is

not

too

warm

-LRB-

so

called

cooled

dialysate

-RRB-

a

normal

high

level

of

sodium

-LRB-

to

mmol

L

-RRB-

which

is

not

more

than

the

normal

concentration

of

sodium

per

liter

plasma

water

a

normal

hematocrit

over

and

optimally

near

but

not

higher

-LSB-

-RSB-

and

a

mode

of

dialysis

based

on

hemofiltration

i.e.

-LRB-

optimally

HDF

-RRB-

are

some

of

the

major

tricks

used

to

enhance

ultrafiltration

tolerance

-LSB-

-RSB-

Intolerance

of

weight

loss

usually

becomes

symptomatic

at

the

end

of

the

dialysis

session

when

the

patient

is

near

his

dry

weight

Continuous

blood

volume

monitoring

during

the

session

should

become

a

real

clinical

support

to

enable

optimum

ultrafiltration

tolerance

-LRB-

notion

of

crash

hematocrit

-RRB-

-LSB-

-RSB-

This

information

is

limited

to

blood

compartment

changes

The

interstitial

space

which

is

mostly

sodium-dependent

is

better

estimated

by

clinical

assessment

of

edema

or

body

weight

-LSB-

-RSB-

Rarely

bed

scales

are

used

to

assess

more

precisely

the

weight

changes

over

a

dialysis

session

For

most

infants

and

children

weighing

less

than

kg

the

need

for

more

than

three

sessions

a

week

may

become

evident

to

enable

adapted

nutrition

i.e.

milk

that

is

water

hence

to

sessions

a

week

are

frequently

prescribed

-LSB-

-RSB-

The

adequate

number

and

duration

of

each

session

should

avoid

partial

fasting

to

achieve

the

weight

needed

to

facilitate

a

short

dialysis

duration

-LSB-

-RSB-

The

volume

of

fluid

used

for

extracorporeal

blood

replacement

at

the

end

of

the

session

should

be

limited

and

preferably

a

glucose

solution

instead

of

saline

solution

be

used

especially

in

infants

without

residual

renal

function

-LSB-

-RSB-

At

the

beginning

of

the

dialysis

session

clinical

manifestations

of

bioincompatibility

may

occur

This

first

use

reaction

is

related

to

the

biocompatibility

of

the

material

in

the

extracorporeal

circuit

i.e.

membrane

lines

or

even

the

needle

either

during

the

first

session

first

contact

with

the

extracorporeal

material

or

thereafter

for

example

in

a

new

dialysis

center

for

holidays

The

major

positive

diagnostic

criteria

is

the

onset

within

min

of

starting

dialysis

of

the

major

symptoms

of

dyspnea

burning

heat

throughout

the

body

or

access

site

angioedema

flushing

or

vascular

collapse

or

with

minor

symptoms

such

as

itching

rhinorrhea

lacrymation

urticaria

or

abdominal

cramping

Even

if

its

occurrence

is

rare

or

underestimated

in

the

event

of

intermittent

minor

symptoms

only

during

the

first

hour

of

session

the

risk

could

be

substantial

Biocompatible

membranes

steam-sterilized

material

adequate

flushing

of

the

circuit

before

blood

connection

are

some

of

the

most

important

prevention

factors

-LSB-

-RSB-

The

dialysis

per

se

should

be

regarded

as

part

of

an

overall

strategy

for

care

including

dietary

adequacy

and

interdialytic

therapy

-LSB-

-RSB-

A

weight

gain

over

dry

BW

during

the

interval

of

two

sessions

is

often

correlated

with

global

non-compliance

-LSB-

-RSB-

In

these

cases

major

outcomes

could

even

occur

first

acute

i.e.

hyperkalemia

or

pulmonary

edema

second

chronic

i.e.

hyperparathyroidism

and

third

long

term

i.e.

cardiovascular

and

coronary

involvement

-LSB-

-RSB-

Conclusions

Hemodialysis

in

children

has

benefited

from

major

progress

over

the

last

years

The

morbidity

of

the

sessions

has

decreased

even

disappeared

seizures

being

exceptional

hypotensive

episodes

or

headaches

rare

and

pain

related

to

the

fistula

puncture

effectively

prevented

by

xylocaine

ointment

The

development

of

urea

kinetic

modeling

enables

calculation

of

the

dialysis

dose

and

indirect

assessment

of

protein

intake

nPCR

Even

if

the

validity

of

these

values

is

questioned

their

combined

analysis

provides

an

assessment

and

therefore

is

a

good

thing

The

patient

also

benefits

from

the

technological

revolution

The

newer

machines

enable

precise

control

of

ultrafiltration

volumetric

assessment

and

continuous

blood

volume

monitoring

during

the

session

buffered

bicarbonate

has

become

a

standard

technique

synthetic

more

biocompatible

membranes

and

specific

material

available

for

babies/infants

have

been

developed

Non

invasive

intervention

for

example

blood

volume

guided

ultrafiltration

have

provided

more

adequate

dialysis

sessions

and

better

dry

weight

assessment

-LSB-

-RSB-

Last

the

availability

of

erythropoietin

-LSB-

-RSB-

and

of

growth

hormone

and

the

promising

results

from

enhanced

dialysis

dose

on

both

growth

and

cardiac

function

-LSB-

-RSB-

all

give

the

dialyzed

child

a

real

increased

quality

of

life

In

theory

reduction

of

dialysis

prescription

to

only

a

urea

dialysis

dose

achieved

by

three

short

-LRB-

-RRB-

dialysis

sessions

should

be

abandoned

for

long

term

dialyzed

children

and

replaced

by

optimum

dialysis

obtained

with

longer

-LRB-

and

more

hours

-RRB-

and/or

more

frequent

-LRB-

daily

to

-RRB-

sessions

-LSB-

-RSB-

But

for

such

a

daily

dialysis

strategy

all

the

costs

must

be

considered

On

the

one

hand

the

financial

cost

can

not

be

neglected

For

the

patient

bearing

the

burden

on

the

other

hand

such

an

intensive

dialysis

prescription

is

acceptable

only

as

an

integrated

therapy

life

project

a

dialysis

transplantation

program

-LRB-

HD

PD

-RRB-

with

special

regard

for

prevention

of

the

vascular

calcification

-LSB-

-RSB-

Daily

hemodialysis

is

one

approach

perhaps

the

only

one

to

achieve

phosphate

purification

-LSB-

-RSB-

and

thereby

maintain

the

calcium

phosphorus

product

in

the

optimum

range

of

to

mL

-LSB-

-RSB-