Intravenous cannulation

This slideshow introduces the basic concepts around intravenous cannulation. Whilst the context is midwifery this slideshow is also suitable for nurses and medical staff.

1. Intravenous Cannulation
Sarah Stewart 2012

http://www.flickr.com/photos/24782931@N00/3341006811

2. Intravenous cannulation
Looking at four key points:
Reasons why midwives need to
be able to cannulate
Preparation
Technique
•Troubleshooting tips
http://www.flickr.com/photos/26406919@N00/313969546

3. Purposes of IV therapy
Fluid replacement
Delivery of medicine
Delivery of blood
or blood products
Consider situations in midwifery practice when this would be
necessary.
http://www.flickr.com/photos/48819968@N00/84515824

4. Reasons why midwives
need to be able to cannulate
PPH
Epidural
Drug treatment
Blood transfusion
Induction/augmentation
Premature labour/PIH/diabetes
LSCS/manual removal/repair of tear
Correct ketosis/?fetal tachycardia/distress
http://www.flickr.com/photos/48819968@N00/84002998

5. Preparation
•Choice of site
–choose veins in hand or
lower arm
–non-dominant side
•Avoid wrist or arm joints,
small, visible veins, areas
of recent inflammation or
cannulation.
•Selected vein should feel
round, elastic, firm and
engorged – not hardened,
bumpy or flat
http://www.flickr.com/photos/29946035@N08/5504530428

6. Preparation
Choice of cannula
–Suitable for both the vein and the
fluid
–16g -18g
•Communication –
-explanation /informed consent
•Local anaesthetic
http://www.flickr.com/photos/44312356@N04/5246179138

7. Technique
Plenty of light
Make sure woman is comfortable – look at what
she is wearing
•Equipment at hand
•Tourniquet - place around the limb 2 – 3 inches
below elbow joint
avoid pulling skin or hair
pull it tight enough to trap venous flow but not to
occlude arterial flow
•place “blue sheet” under arm and ? pillow

8. Cleaning
•Clean with alcohol swab and allow to dry naturally
•Do not re-palpate after cleaning
•Approaching vein
Ask woman to flex wrist
Bend thumb under fingers (if placing cannula in basilic
vein)
•Pull skin below site of insertion

9. Veins of the Hand
1. Digital Dorsal veins
2. Dorsal Metacarpal veins
3. Dorsal venous network
4. Cephalic vein
5. Basilic vein
Veins of the Forearm
1. Cephalic vein
2. Median Cubital vein
3. Accessory Cephalic vein
4. Basilic vein
5. Cephalic vein
6. Median antebrachial vein

10. Inserting cannula
Insert cannula at low angle (notice flash back of blood into
chamber of cannula)
Reduce angle of cannula slightly and advance cannula
along another 2 – 3 mm
Withdraw needle 5 – 10 mm so it does not go through wall
of vein and then advance plastic cannula along
vein
Remove needle and dispose
Take blood samples for FBC and group
and hold
Release tourniquet
Press on vein above cannula to avoid blood spillage
•Attach to IVI or flush with saline before screwing on
injection cap(if needle-less system, attach rubber bung
before connecting IVI or flush)

12. Applying dressing
Apply transparent dressing so that cannula and
infusion tubing is secure and insertion site can be
observed
Tape tubing further up the arm so that it is secure
and not pulling on cannula
Make sure tape is not interfering with transparent
dressing or injection cap
Immobilize arm if insertion site is in wrist or
elbow joint
•Make sure woman is comfortable and can mobilise
fingers and arm

13. Troubleshooting tips

Backflow stops when you remove the
stylet?
Oh dear! You may have pushed the stylet
through the opposite wall of the vein.
In this case, retract the stylet slightly until
blood flashback appears again, then
advance the cannula into the vein and
release the tourniquet.
•Do not reintroduce the needle.

14. Troubleshooting tips
Don’t panic if you are
unable to withdraw blood
for sample. The final test
is whether the IVI runs
properly.
If haematoma forms;
insertion site is very
painful; IVI doesn’t flow;
cannulation has not been
successful, so stop
procedure.
http://www.flickr.com/photos/33987777@N00/223015379

15. Troubleshooting tips
Have two attempts
then call for help.
http://www.flickr.com/photos/30562035@N00/3087928130

16. •Do not pass cannula through
valve (which looks like a
bump in the vein) as it is very
painful.
•Use bifurcated vein when
possible (looks like inverted
V). It is easier to cannulate
than a single vein as it is
more stable and less likely to
roll.
•Be positive.
•Don’t forget to reassure
woman.
http://www.flickr.com/photos/29174632@N00/1171788641

17. Common problems during
cannulation procedure
Tourniquet too tight, too loose, too high, too low
Failure to release tourniquet promptly after vein is
sufficiently cannulated
Stopping too soon after insertion of the stylet so that only
the needle goes into the vein
Failure to recognise the cannula has gone through the vein
wall
inserting the cannula too deep so that it is under the vein –
very painful for woman and cannula won’t move freely
•failing to penetrate the vein – angle of needle is too steep
or not steep enough causing needle to ride along the vein
or on top the vein

18. Local complications
•Thrombosis – obstruction to flow due to platelet formation
at site if injury (by cannula)
•Thrombophlebitis – thrombus plus accompanying
inflammatory response

19. Local complications
•Phlebitis – inflammation of inner lining of vein usually
due to mechanical or chemical trauma. More
susceptible to infection.
- redness, swelling, pain, warm to touch, tender,
palpable venous cord (if left too long), possible
pulmonary embolism
- diagnosis: flow stops when apply pressure above
cannula tip

20. Phlebitis
http://www.nova.edu/~stmartin/IV/IVTherapyPrintout.html

21. Local complications
Treatment – stop infusion, remove cannula, resite, apply
warm compress, elevate and rest arm
Prevention – regular monitoring of IV site & cannula,
appropriate choice of site, secure taping, ask woman to
report any discomfort

22. Local complications
Infiltration / Extravasation / Tissueing
- leakage of IV fluid into surrounding tissues
- signs - pain, tightness, skin cool to touch, oedema, IV
rate slowed
-Diagnosis – flow continues when apply pressure
above cannula tip or halo appears when shine torch on
oedema
-Treatment – stop, remove, re-site, warm, elevate

23. Local complications
•Clotted cannula due to
--Inadequate flushing or
--fluids run dry or
--Increased venous pressure above site (BP cuff)
--Turning off to allow mobilisation
Noted by blood backing up tube or flow stopped
Intervention – first check height of bag, clamps, position
- aspirate, irrigate if no return, resite if need

24. Local complications
Air embolism
Catheter embolism
– do not re-introduce needle

25. Women should have no more
than 2 ½ litres in 24 hours
A pregnant woman already
carries extra body fluid. Anti-
diuretic hormone is increased
in labour by fear and anxiety,
as does oxytocin
Increased fluid volume cause
water intoxication\
Mother – oedema, headache,
vomiting, convulsions
Baby – convulsions, apneoa,
resp. distress, neonatal weight
loss
Epidural – if hypotension
persists, use ephidrine instead
of large volumes of fluid
http://www.flickr.com/photos/42998601@N00/35590995

26. Sodium chloride 0.9%
isotonic
Most commonly used - administer
drugs, eg syntocinin, magnesium
sulphate. Replaces H20, Na, C in
dehydration.
Haemodilution can occur. Overload.
Hartmann's
(lactated Ringer's solution)
isotonic
Epidural - pre-loading dose to
counter-act hypotension. Replaces
H2O and electrolytes.
If in doubt, use Hartmanns.
Watch for overload. Ephedrine should
be used if hypotension persists.
Dextrose 5%
isotonic
Rarely used Increases maternal blood sugar -
increases fetal insulin - fetal
hypoglycaemia - jaundice.
Haemaccel
Synthetic polygeline colloid
Plasma volume expander Not so commonly used as was.
Whole blood Plasma volume replacement,
replaces red blood cells (hb),
replaces clotting factors, source of
fresh blood.
Increases O2-carrying capacity,
administer through blood filter, do not
infuse cold, risk of blood borne
infections.
Packed cells Treat anaemia, used with women
with low hb but adequate blood
volume.
Increases O2-carrying capacity,
replaces low hb without extra plasma
volume preventing overload, administer
through blood filter, risk of blood borne
infections.

27. References
•Johnson R, & Taylor W. (2006). Skills for midwifery
practice. Elsevier: Edinburgh.
•Chapman V.(2003). The midwife’s labour and birth
handbook. Blackwell Publishing: Oxford.
•London, G. (1990). Nutrition and hydration in labour. In:
Intrapartum care: a research-based approach. J.
Alexander, V. Levy, S. Roch (Eds.). London: Macmillan.