What are the options for
dialysis access
Catheter base: Peritoneal
dialysis and
Haemodialysis via venous catheters
Tissue Base: AV fistula
formation
What are the other
indications for vascular access
•
High flow angioaccess for dialysis
•
Sclerotic solutions are administered IV – chemotherapy, TPN
•
Frequent administration of blood or
blood products or drawing of
blood is required
How do you insert a
central venous catheter
In
an
appropriately consented, investigated and prepared patient
Preparation
should
include a FBC and coag screen.
Pre-op
venous
duplex should be arranged in patients with previous lines or
history to suggest
venous obstruction
•
My
preference is always for IJ canulation because of the lower rate
of stenosis
and fewer implications for subsequent fistula formation
•
Supine.
Rolled fluid bag between shoulders. Head ring. 5 degrees
Trendelenberg to
distend veins and reduce the risk of air embolus. Turn head to
contre-lateral
side. Sterile prep and drape. ECG monitoring, SaO2 and oxygen
via nasal prongs.
•
Mark
the landmarks with pen – SCM, Clavicular head and level of
cricoid. I use
fluoroscopic control.
•
I
approach the vein about 2 fingers above the clavicle. I check
the contents of
the kit, flush all lumens of the catheter with saline and check
for any leaks
in catheter.
•
I
place the thumb of my non-dominant hand on the Carotid pulsation
and my index
finger on the sternal notch for orientation.
•
I use
my thumb to protect the carotid artery medially.
•
Infiltrate
1% lignocaine 10ml
aspirating before
injection.
•
I use
a 23 needle with a 10ml syringe to locate the vein by inserting
it into the
skin and pointing at the clavicular head until drark blood is
draw. If bright
red blood comes out, I withdraw the needle and press for 10
minutes.
•
Once
the IV is located with the small needle, I use a larger 16g long
needle with a
10ml syringe filled with 3-4ml of saline to canulate the vein.
Some kits have
syringe which allows passage of the guidewire down the hub of
the syringe. If
the kit does not include this, I remove the syringe and advance
the guidewire
through the needle. I use fluoroscopy to ensure that the
catheter passes to SVC
and watch the ECG monitor for ectopic beats.
•
Once I
am satisfied with the guidewire position, I insert remove the
needle and
exchange it for the dilator over the guide wire and dilate the
tract into the
vein.
•
I
remove the dilator and make a small incision over the wire exit
site.
•
I
thread the catheter over the wire to the desired length to the
estimated
junction of SVC and RA (Level of angle of Louis).
•
I
secure the flange to the catheter and suture the flange with two
0 nylon
sutures and cover with tegaderm.
Why do you use the IJ
•
The
risk of venous stenosis is greater in the subclavian vein (50%
in 2 weeks).
This substantially
increases the risk of
fistula failure or swollen arm when an AV fistula is constructed
and so the IJ
is preferential access site for renal patients (IJ stenosis rate
<10%).
•
It is
easier to use US-guided technique in the IJ.
•
Arterial
puncture is easier to control.
Where do you place the
puncture site for the
subclavian vein
•
One cm
below the junction of inner 1/3 and outer 2/3 of calvicle.
•
I
place the non-dominant hand on the chest with index finger
pointing to the
sternal notch.
•
I
infiltrate local.
•
I walk
the needle down to the undersurface of the clavicle and direct
the needle to
the sternal notch with the needle shaft almost parallel to the
floor.
How do you use US
•
I use
a 5MhZ linear US transducer
•
I use
the device before sterile prep to provide general orientation
and adjust the
settings on the machine. I mark the IJ and CA: the IJ is the
larger, more
superficial and more compressible vessel
•
I then
cover the probe with sterile sheath and use sterile jelly during
catheterization.
•
I use
the US probe transverse to the long axis of the vein.
•
I
stand at the head of the bed with the transducer in the
non-dominant hand
transverse to the long axis of the vein.
•
I insert
the needle cephalad to the probe, with
the needle seen as a bright spot in the vein.
•
The
needle is seen as a hyper-echoic spot.
How do you insert a
tunnelled line (Hickman type)
•
Canulation
of the vessel (IJ or subclavian) is the same using a Seldinger
tecnhque.
•
The
vessel is canulated using a canula with a peel away outer
sheath.
•
An
incision is made on the anterior chest wall, usually over the 4th
IC
space.
•
A
tunnelling device is inserted from the chest wall incision to
the subcutaneous
tissue underlying the vessel puncture site. A heavy suture is
pulled back into
the remote exit site and tied to the tip of the silastic
catheter which is then
pulled back through exit site where the vessel was punctured.
•
The
Dacron cuff is secured 4cm from the skin exit site.
•
The
length of silastic catheter required is estimated so that it
will lie at the
junction of SVC and RA. The silastic catheter is flushed with
saline
•
The catheter
is trimmed.
•
The
introducer is removed leaving the peel-away catheter in place.
•
The
silastic catheter is threaded down the peel-away catheter which
is then peeled
away as the silastic catheter is advanced.
•
The
skin is closed over the vessel puncture site with 3/0 Nylon. An
occlusive,
opsite dressing is placed over the puncture site.
•
The
tunnel exit site is closed around the catheter with interrupted
3/0 nylon
either side of catheter.
How do you insert the
infuse-a-port type device
•
It is
the same as a hickman line except a pocket is created on the
chest wall,
exposing the pectoral fascia. The infusion port is fixed to
chest wall by
placing sutures that pass through the flanges of the port onto
the fascia of
the chest wall in 4 places to ensure that the port will not
flip.
•
It is
vital that a non-coring Huber needle of no more than 22g is used
to avoid
damage to the silicon rubber septum
What are your
post-procedure instructions
•
Monitoring
ECG, SaO2 and BP for 1 hour post procedure whilst an erect CXR
is performed to
check position and exclude pneumothorax.
•
If a
penumothorax is small
(<30%) and the patient is asymptomatic, it can be observed
with observation
in hospital and repeat CXR in 6 hours. A chest drain is
required if it is enlarging
or large or the patient is symptomatic.
What are the modes of
access for dialysis
External
angioaccess
Internal
angioaccess
Prosthetic
jump
graft
What are the types of
external angioaccess
•
Non-tunnelled
central venous catheter inserted into subclavian, IJ, femoral –
usually used
for emergency access or short term <2 weeks
•
Tunnelled
central venous catheter inserted into subclavian, IJ
•
Peripherally
inserted central catheter.
•
Catheters
may be totally implantable (Port-a-cath or infuse-a-port) or
external
(Hickman).
•
Catheters
may have a Dacron cuff which prevents infection
What are the devices
used for dialysis
•
Dual
lumen silicone rubber or polyurethane catheters (Vascath or
Permcath)
•
Soft
and placed using the Seldinger technique in the IJ or EJ vein
using a peel-away
sheath.
What are the problems
peculiar to dialysis central
venous lines
•
Recirculation
of blood via the
catheter. When
placed in IJ there is only about 5%
recirculation. This is a more common problem in femoral vein
catheterization than
IJ or SV
•
Venous
stenosis caused by temporary access may
complicate subsequent fistula formation. More common with
subclavian than IJ placemnt of
catheters
What are the
complications of central venous catheter
insertion
•
Immediate
§ Pneumothorax (1-4%),
haemothorax, arterial
injury, air embolus, injury to nerves (Vagus, sympathetic trunk,
phrenic,
femoral), bleeding, great vessel injury, inability to advance
the catheter,
pericardial tamponade.
•
Early/late
§ Thrombotic: Presents as
inability to draw
blood. Clot may be in catheter or in vessel surrounding catheter
(fibrin
sheath) or both. May be due to irritation of wall by catheter,
hypercoagulable
state or irritatnt nature of infusion. Contrast radiograph to
check position
and integrity of catheter is necessary. If the catheter is
surrounded by fresh
thrombus, use a small amount of tPA to lyse the clot. Treat for
DVT with
heparin and warfarin.
·
Prevention of thrmbosis includes low dose
warfarin (1mg) or heparin flushing of catheter
§ Catheter infection: Rate
is about 2 infections per 1000 catheter
days. More common with
thrombosis, multi-lumen catheters, immuncompromise. May be early
or late. May
be exit site or catheter-related sepsis. Diagnosis can be
obscure. Most
definitive is catheter tip culture, this requires catheter
removal.
Alternatives include CFU counts (>15 CFU/ml confirms
diagnosis) and ratio of
catheter to blood culture CFU (10:1 confirms diagnosis).
Prophylatic measures
include strict asepsis at insertion, coating the catheter with
Abx or anti-septic
solution (internal and external coating with Rifampicin appears
superior).
·
Treatment options –
Systemic Abx
via the line directed
against the offending organism. If deterioration or failure to
improve after 48
hours then remove catheter.
Removal of catheter is appropriate for
severe infection with
systemic sepsis.
Trying
to conserve
the catheter may be appropriate for patients needing long-term
access where
other sites are not available or need to be conserved with
mild, superficial
infection and no sepsis.
For
exit site
infection, the catheter
can be exchanged
over a guide-wire and a new exit site chosen.
§ Mechanical complications –
The catheter is
malpositioned, there is shearing between the clavicle and first
rib. If
malpositioned (eg passed down subclavian/axillary branch) must
be
re-positioned. If shearing between the clavicle and first rib is
suspected then
remove to prevent breaking and embolization.
What are the types of AV
fistula
•
Natural
and prosthetic
•
The
complications and costs of natural fistulas are lower and these
are preferable.
What
are the types
of natural fistula
•
Site:
o
Radiocephalic
at wrist – Brescia-Comino
o
Posterior
radial branch-cephalic (snuff box fistula).
o
Ulnar
cephalic forearm
o
Radial
basilica (Fienberg)
o
Brachial
cephalic (antecubital vein to brachial artery)
o
Brachial
basilica
•
Type
of anastomosis
o
Side
artery to side vein – higher rate of venous hypertension in hand
(swelling and
ulceration)
o
End-vein
to side artery
o
End
artery to side vein
o
End to
end – higher rate of thrombosis
How do you evaluate a
patient for a fistula
•
First
preference is for non-dominant radio-cephalic (Brescia-Comino
graft)
•
Allen’s test to confirm adequate
collaterals via ulnar
artery
•
Duplex mapping
– an artery
>2mm and vein >2.5mm
•
If
suspicion of vein stenosis then venogram to allow visualization
of stenosis
behind the clavicle
How do you make an AV
fistiula
Bresia-Cimino
(radiocephalic)
•
In an
appropriately consented, investigated and prepared patient
•
Preparation
should include a FBC and coag screen.
•
Side
should be marked. Preferably non-dominant hand
•
Pre-op
venous duplex should be arranged in patients with previous lines
or history to
suggest venous obstruction
•
GA.
Supine. IV cefazolin. Arm table. Sterile prep and drape
including preparing the
hand so that perfusion can be assessed.
•
Incision
is 4cm long 1cm lateral to the radial artery starting just
distal to the
proximal skin crease of the wrist.
•
Use
diathermy to stop dermal bleeding. Using skin hooks deepen
incision down to deep fascia and divide
the fascia over the medial aspect of brachioradialis tendon
•
I
elevate skin flaps laterally and locate the cephalic vein.
•
I
isolate a sufficient length of cephalic vein to easily reach the
radial artery.
I mark the anterior surface of the vein
using indelible
pen to ensure that the vein is not twisted during
transposition.
•
5000u
of heparin is given IV.
•
I
ligate the vein distally and any side branches of it.
•
I
control any back bleeding from the vein with a vessel loop and
spatulate the
divided end flush with hep-saline
•
Place
self-retaining retractor.
•
I
expose the radial artery over 10mm.
•
I
sling the artery proximally an distally using silastic vessel
loops.
•
I use
sharp dissection with scissors to separate the venae commitantes
from the
artery over about 10mm.
•
I
place silk ties twice around the branches of the radial artery to occlude and control
them, but do not tie.
•
Bulldog
clips are placed proximally and distally on the artery.
•
A
longitudinal arteriotomy is created about 6mm in length.
•
I
complete my anastomosis using 7/0 double-ended prolene
performing the back wall
first from inside the lumen and the front wall from outside the
lumen.
•
Before
the final suture is tied, I release the proximal clamp and flush
the air from
the vessels and then replace it
•
I
finally flush with Hep-Saline and then tie the suture with 6
throws.
•
I
release proximal and distal arterial clamps and the vein vessel
loop.
•
I
remove all the side branch ties, check haemostasis, washout and
ensure that the
hand is adequately perfused.
•
I
close the wound in layers using 3/0 vicryl for fascia then fat.
4/0 Nylon to
skin.
•
Post-op
orders: Limb in kept warm in a foil blanket with moderate
elevation to prevent
swelling and regular hand observations.
What are the
complications
Immediate
(<24
hours)
•
Bleeding,
arterial thrombosis or embolism leading to hand ischaemia, air
embolus
•
Damage
to superficial branch of radial nerve
Early
(30 days)
•
Failure
to mature
•
Thrombosis
•
Cardiac
failure in patients with marginal cardiac reserve where flow
exceeds 500ml/min.
Can be reduced by placing Teflon band around outflow
•
Arterial
steal syndrome – more common is proximal fistula (30%). Treated
by ligation of
fistula or narrowing the venous limb. Avoided by end venous to
side arterial
Late
•
Stenosis
of venous limb
•
Aneurysm
formation – repeated needle punctures
•
Thrombosis
•
Venous
hypertension - causing swelling, pigmentation, induration,
ulceration. More
common in side to side anastomosis
•
Infection
How are prosthetic
grafts classified
By
position
•
Radial
artery in wrist to cephalic vein just below elbow – low patency
rate due to low
flow rate
•
Brachial
artery to antecubital vein forearm loop
•
Brachial
artery to axillary vein arm loop
•
Superficial
femoral to Saphenous vein
•
Popliteal
artery to femoral vein
•
Axillary
artery to axillary vein across the chest
•
Brachial
artery to IJV
•
The
arm fistulas are constructed preferentially
•
Forearm
fistulas have a higher rate of thrombosis but a lower risk of
distal ischaemia
than arm fistulas
•
Lower
limb fistulas are used when there are no useable vessels in the
upper limbs.
Lower limb fistulas are very poor choice in older patients,
patients with
diabetes or arterial disease
What are the technical
aspects of prosthetic fistulas
•
Use a
6mm non-ringed straight PTFE graft.
•
Rotation
or pinching of the graft must be avoided
•
Although
the fistula can be used straight away, allowing 1-2 weeks for
maturation may
minimize complications from bleeding by allowing tissue
ingrowth.
How do you construct a
Brachial artery to antecubital
vein forearm loop
•
In an
appropriately consented, investigated and prepared patient
•
Preparation
should include a FBC and coag screen.
•
Side
should be marked. Preferably non-dominant hand
•
Pre-op
venous duplex should be arranged in patients with previous lines
or history to
suggest venous obstruction
•
GA.
Supine. IV cefazolin. Arm table. Sterile prep and drape
including preparing the
hand so that perfusion can be assessed.
•
Incision
is 5cm long 1cm distal to elbow crease
•
Use
diathermy to stop dermal bleeding. Using skin hooks and cat’s
paws to lift skin
deepening incision down to deep fascia to expose the bicipital
aponeurosis and
brachial artery.
•
I
elevate skin flaps taking great care not to damage the cephalic,
median
cephalic, median basilic and median antecubital veins.
•
I
insert a self-retaining retractor
•
I
retract some fibers of the bicipital aponeurosis laterally to
expose the
brachial artery, just lateral to the biceps tendon. I take great
care not to
damage the median nerve which lies just lateral to the artery
•
I
isolate about 10mm of artery passing silastic vessel loops
around the proximal
and distal limits
•
5000u
of heparin is given IV.
•
I
separate the venae commitantes from the artery without dividing
them.
•
Any
side brnaches of the artery are controlled with double slinging
with 2/0 silk
ties without ligation
•
I
control the vein vessel loops around the proximal and distal
limits
•
I make
a counter-incision in the forearm about 12 distal.
•
I
tunnel the PTFE graft in a U-shaped loop about 6cm wide to the
distal incision
ensuring that it is not twisted
•
Bulldog
clips are placed proximally and distally on the artery.
•
I
spatulate the PFTE graft
•
A
longitudinal arteriotomy about 8mm on the ventral surface of the
artery is
performed using scalpel and potts scissors and flushed with
hep-saline
•
I
complete the arterial anastomosis using 6/0 double armed prolene
continuous
suture.
•
I open
the proximal bulldog to flush the air from the graft Controlling
the venous
limb of the graft first with fingers then a bull dog.
•
I
perform a longitudinal venotomy about 8mm and complete my
anastomosis using 7/0
double-ended prolene performing the back wall first from inside
the lumen and
the front wall from outside the lumen.
•
Before
the final suture is tied, I release the proximal clamp and flush
the air from
the vessels and then replace it
•
I
finally flush with Hep-Saline and then tie the suture with 6
throws.
•
I
release proximal and distal arterial clamps and the vein vessel
loop.
•
I
remove all the side branch ties, check haemostasis, washout and
ensure that the
hand is adequately perfused.
•
There
is often bleeding from suture holes. I cover the holes with
Surgicel and apply
gentle pressure for 5 minutes.
•
I
close the wound in layers using 3/0 vicryl for fascia then fat.
4/0 Nylon to
skin.
•
Post-op
orders: Limb in kept warm in a foil blanket with moderate
elevation to prevent
swelling and regular hand observations.
What are the
complications
Immediate
(<24
hours)
•
Bleeding
is more commonly from suture holes
•
Arterial
thrombosis is from narrowing the inflow or outflow or kinking of
the graft
•
Embolism
leading to hand ischaemia, air embolus
•
Damage
to superficial branch of radial nerve
Early
(30 days)
•
Failure
to mature
•
Thrombosis
– often due to low blood pressure or excessive external pressure
•
Cardiac
failure in patients with marginal cardiac reserve where flow
exceeds 500ml/min.
Can be reduced by placing Teflon band around outflow
•
Venous
hypertension - causing swelling, pigmentation, induration,
ulceration. More
common in side to side anastomosis
•
Arterial
steal syndrome – more common is proximal fistula (30%). Treated
by ligation of
fistula or narrowing the venous limb. Avoided by end venous to
side arterial
o
Complications
can be treated using rapid taper 4 to 7mm grafts.
Late
•
Stenosis
of venous limb – can be repaired by a patch graft, angioplasty
or bypass
•
Aneurysm
formation – repeated needle punctures. Can be treated with
covered stents
•
Thrombosis
– late thrombosis is due to venous intimal hyperplasia at or
distal to the
anastomosis.
•
Infection
is a major problem in prosthetic grafts. Commonly S aureus or S
epidermidis.
Infection rates in IV drug users or HIV patients are up to
30-40%
o
If it
involves the suture line, the risk of false aneurysm is too high
and the graft
removed and the artery re-constrcted.
o
Infection
not involving the suture line can be treated with abx and
drainage of infection
•
The
patency rates of prosthetic jump grafts are less than autogenous
AV fistulas.
The patency is greater for more proximal fistulas, but the
ischaemic
complications are more common.
How can the long term
patency of fistulas be improved
•
Early
intervention for graft stenosis with PTCA extends the life of
the graft.
•
Graft
and fistulas should be monitored by feeling for a thrill,
measuring
pressures (3
pressures >150mmHg with
flow rates of >250ml/min indicates a venous stenosis),
Doppler examination.
•
When
there is a thrill in the entire length of the graft or fistula
then the flow
rate is >450ml/min.
•
When
there is a stenosis >50% with haemodynamic compromise
(reduced thrill,
increased pressure) the intervention is recommended.
o
The
options for intervention are surgical or endovascular.
o
Endovascular
interventions include Baloon angioplasty (30atm; 15min). Cutting
balloon and
covered stents have also been used
o
Surgical
therapy seems to be superior for venous stenosis than
endovascular therapy, but
is more invasive and requires temporary access.
o
Percutaneous
techniques are also used for central venous stenoses
How do you insert a
peritoneal dialysis catheter
I
use a
laparoscopic approach to ensure the correct position of catheter
tip
In
an
appropriately consented, investigated and prepared patient
GA.
Supine. IV
Abx. Sterile prep and drape. In the patient who is not anuric I
insert an IDC
•
Open
Hasson canulation. P12 F12. Inspect the peritoneal cavity for
adhesions,
omentum obscuring entry into pelvis ect.
•
I make
a 4cm vertical paramedian incision below the umbilicus.
•
I
divide the anterior rectus sheath and split the muscle to expose
the
peritoneum.
•
I insert
an Vicryl purse string suture in the peritoneum.
•
I
insert the tenckoff catheter through the purse string and guide
the tip into
position in the pouch of Douglas.
•
If I
cannot easily position the tip in the pelvis, I insert a single
5mm port on the
opposite side to that chosen for the catheter at the same level.
•
I
position the first Dacron cuff in the rectus muscle and tie the
purse string
suture to ensure a water-tight seal.
•
I
tunnel the exit site of the catheter a short distance from the
surgical incision
leaving the second cuff in the subcutaneous fat just superficial
to the fascia.
•
I
remove the laparoscopic ports and deflate the pneumoperitoneum.
I close the
Umbilical port under vision with 0 Vicryl.
•
I
instil fluid into the peritoneal cavity and confirm there is no
leakage around
the purse string. If there is leakage I place additional sutures
to ensure
water-tight closure.
•
I
close the anterior rectus sheath around the catheter using 0
Vicryl interrupted
suture.
•
I
close the skin incision using 3/0 Nylon and drain the fluid from
the peritoneal
cavity.
What are the
complications of peritoneal dialysis
catheter placement
Immediate
•
Leakage
of dialysis fluid
•
Bleeding
into peritoneum
•
Bowel
or bladder perforation
•
Subcutaneous
haematoma from tunnelling
Early
•
Hernia
formation
•
Ileus
post-operatively
Late
•
Exit
site infection – Most commonly S aureus. 0.8 per patient years
•
Mechanical
– Poor inflow can be caused by obstruction of some catheter
holes, omental
wrapping or catheter displacement. Complete blockage is caused
by kinking,
blockage of all catheter holes, omental wrapping of entire
catheter.
•
Peritonitis – Average 1.3 episodes
per patient year.
There
are four routes of infection –
around dialysis tubing
through dialysis tubing
contamination of peritoneal cavity (eg
diverticulitis or PID)
blood-borne infection
Usually caused by a single
pathogen. Gram-positive
cocci (Coagulase negative Staph -60%), Gram negative bacilli
(30%), Pseudomonas
10%. It is treated with a combination of IV and peritoneal Abx
guided by gram
stain and culture. A Y connector with a closed system reduces
the incidence of
peritonitis.
The
survival of CAPD catheters is 85% for 1 year and 80% after 3
years.
Survival
is less in diabetics