13.0 Intravenous (IV) cannulation
Training in principles and practice of intravenous cannulation will help reduce the
stress for patient and practioner alike and minimise associated complications of
cannulation.
The insertion of any intravenous device, the administration of intravenous therapy
and subsequent withdrawal or removal of the device requires strict adherence to the
principles of asepsis. This principle requires that all equipment and materials should
be sterile.
Areas to be covered
1.
2.
3.
4.
1.
Anatomy & Site Selection
Insertion procedure
Infection control
Potential complications and risks
Anatomy & Site Selection
The main veins used are illustrated in figures 1 and 2. The exact position of such
veins may vary from one individual to another.
Figure 1. Superficial venous anatomy of the dorsum of the hand
Basilic
vein
Cephali
c vein
MEDIAL
(ULNAR)
LATERAL
(RADIAL)
Figure 1. Superficial veins of the dorsum of the hand
Advantages: First choice for venous access because veins are accessible,
superficial, visible, stabilized by underlying bones and way from vital structures.
Disadvantages: Veins are poorly tethered and tend to be mobile during cannulation,
subject to vasoconstriction in cold weather and in very anxious patients. The site is
also rather painful (consider use of EMLA® or Ametop®)
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Figure 2. Vascular anatomy of the Right antecubital fossa and ventral arm
Cephali
c vein
Biceps
muscle
Basilic
vein
Biceps
tendon
Median
cephalic
vein
Median
vein
LATERAL
(RADIAL)
MEDIAL
(ULNAR)
Brachial
artery
Radial
artery
Ulnar
artery
LATERAL
(RADIAL)
MEDIAL
(ULNAR)
Figure 2. Vascular anatomy of the upper arm (including the antecubital fossa)
Second choice for venous cannulation (first if large volumes of fluids need to be
given quickly) is the large veins of the antecubital fossa – the cephalic (lateral) and
basilic (medial) veins. Because of the proximity of the brachial artery and median
nerve to the basilic vein, the Cephalic vein in its lateral position is usually the vein of
choice.
Advantages: Larger veins, which are usually well tethered and even when not readily
visualised, are usually palpable.
Disadvantages: The proximity to vital structures (as above) and movement at the
elbow joint (an arm board may be needed if the patient is unable to keep the arm
straight themselves).
Veins and Sites to Use (in general):
Distal veins first
Easily palpable veins with good capillary refill (it is better to go for a vein you
can palpate but not see, rather than a vein you can see but not feel).
Veins in the non-dominant side
Veins opposite to surgical operation side
Veins with largest diameter (in general)
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Veins clear of vital structures such as arteries (a major advantage of the
dorsum of the hand)
Veins and Sites to Avoid (in general):
Areas of flexion
Veins close to arteries (e.g. medial veins of the antecubital fossa)
Obvious valves
Small visible superficial veins
Veins affected by previous use or sclerosed (e.g. in IV drug abusers)
Infected sites
Broken skin
Limb to be involved in future surgery (e.g. for radial forearm free flap)
Vessels distal to a fracture
Methods of improving venous filling:
Soft quick release tourniquet applied proximal to the cannulation site
Open and closing the fist
Lower the limb below the level of the heart
Gentle slapping over vessel (this causes a minor inflammatory response with
histamine release and vasodilation)
Application of warmth – warm compress or emersion of the limb (or opposite
limb) in warm water
Time – allow filling, don’t rush
2.
Insertion procedure
The key to successful cannulation (and thus minimising stress to patient and clinician
alike) is careful preparation of the chosen site and good well-practiced technique.
Pre-cannulation assessment
Obtain informed consent (usually verbal)
Check treatment plan
Note relevant medical history – particularly any allergies
Use tourniquet to assess suitability of veins – try an alternative site if a vein is
not readily identified
Equipment (ensure all products are in-date)
Skin cleanser (such as Steret®) – allow to dry before cannulation and avoid
contact with prepared site
Tourniquet
Dressing pack (or surgical tape) – to secure cannula. Should allow visual
inspection of the insertion site
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Cannula – smallest appropriate cannula should be used. The size of cannula
depends on the reason for cannulation. The most widely used canulae are
“venflons”.
For IV drugs a blue or pink venflon may be appropriate. If repeated doses
have been prescribed, keep the cannula patent with either a slow infusion of
crystalloid or by regular flushes with a dilute heparin solution.
For routine IV infusion of crystalloid use a pink or green venflon.
For rapid infusion of crystalloid or blood transfusion use a brown venflon.
The rate of infusion is dependent on the cannula NOT the vein. Use a
short, wide cannula for rapid infusions (“short & thick does the trick”
i.e a brown venflon)
Latex gloves
Sharps container
Intravenous flush – sterile saline or water for injection
Luer lock connection or bung
Environment
Bed or seating for the patient
Seating for the practioner
Well supported limb
Good lighting
Trolley or tray for equipment (Cannulation should not be performed in
carpeted areas unless steps have been taken to ensure any potential blood
spillage can be contained by fluid resistant preparation sheet beneath the
cannulation site)
Always use aseptic technique
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INSERTION PROCEDURE
Prepare patient
Prepare equipment
Wash hands
Put on gloves
Skin preparation
Apply tourniquet
Adopt appropriate cannula grip
Ensure cannula is bevel up
Apply skin traction
Angulation 10-30° - dependent on vein
depth
Insert cannula and look for venous
blood (dark) in flashback chamber
Lower angle of cannula and advance
2mm
Retract stylet 3-4mm, note secondary
flashback along cannula and advance
cannula into position
Release tourniquet
Apply digital pressure beyond cannula
tip or elevate limb above the level of
the heart
Remove stylet and dispose of in sharps
container or on sharps pad
Attach Luer lock connection
Hold cannula in place and flush to
ensure correct positioning (usually prior
to securing with tape)
Secure cannula with dressing
Document procedure
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3.
Infection control
There are many potential sources of contamination, which may result in infection
during IV cannulation. Standard precautions should be taken for all procedures to
minimise infection risk before, during and after cannulation. Bacteria and viruses are
the most common infectious agents.
Standard precautions
Skin
The practioner must cover all cuts or abrasions with a waterproof dressing
Gloves
Well fitting, clean gloves must be worn throughout the procedure to prevent
contamination of the hands by blood/body fluids. Latex is the material of
choice unless contraindicated.
Handwashing
Thorough handwashing is still essential and is the fundamental
universal precaution between procedures and patients
Aprons
Where there is a possibility of blood spillage
Eye protection
Wear if there is danger of blood/body fluid splashes
Sharps Container
NO needle re-sheathing prior to disposal into a sharps container
4.
Potential complications and risks
Phlebitis
Phlebitis (inflammation of the vein) is the most common complication with peripheral
IV cannulation. 3 types of phlebitis are recognised:
i. Chemical
ii. Mechanical
iii. Infective
Management of cannulation related infections
Remove cannula
Send cannula tip for culture and sensitivity
Implement local treatment protocol
Replace cannula (at alternate site) and continue therapy as prescribed with a
fresh cannula
Other potential complications:
Haematoma, infiltration, extravasation, air embolism, catheter embolism,
transfixation, intra-arterial injection.
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Extravasation
Seen when the cannula fails to penetrate the lumen of the vein completely or
completely transects the vein and results in the cannula lying in the subcutaneous
tissues. Flushing with saline results in a lump – if seen fluid should be discontinued
and the site massaged to disperse the fluid or drug. If a significant quantity of fluid
has been extravasated it may require drainage to stop necrosis. Extravasation is
more of a concern with irritant substances such as Diazepam, TPN (total parenteral
nutrition), glucose or barbiturates.
Intra-arterial injection
Is a rare complication of IV cannulation due to incorrect positioning of a cannula into
an artery. Avoided by good IV cannulation technique and choice of most appropriate
veins, away from other vital structures (as above). When using veins of the
antecubital fossa only those superficial and lateral to the biceps tendon should
usually be used in order to avoid the median nerve and brachial artery. If bright red
rather than dark blood is observed in the flashback chamber this indicates intraarterial cannulation. The patient will report pain and a test flush with 0.9% saline will
classical produce pain radiation down the arm. If observed, injection should be
terminated immediately, the cannula should be removed, firm pressure applied and
the arm should be elevated to prevent haematoma formation.
The main concern with intra-arterial injection is the potential for arterial spasm (seen
with injection of irritant drugs e.g. diazepam). Brachial artery spasm is dangerous
characterised by intense burning radiating towards the hand, blanching of the skin
and weakening and eventually loss of radial and ulnar pulses. Without prompt
treatment blood coagulates, causing thrombosis, ischaemia and ultimately gangrene.
Treatment involves keeping cannula in situ and injection of 1% procaine to promote
vasodilatation and pain relief and transfer of the patient to hospital for further
treatment, including the use of anticoagulants such as heparin.
Risks to healthcare workers (HCW)
Incidence of sharps injuries:
Account for 16% of all hospital related injuries
16% are related to cannulation
24% are phlebotomy related
Risk of acquiring infection from needle stick injury (from a known carrier):
Hep B virus
Hep C virus
HIV
1 in 3
1 in 100
1 in 300
Best and safest practice
Where gloves whenever potential blood contact is anticipated
Change gloves between patients
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Use eye protection
Avoid sharps were possible
Keep up to date with current practice including local policies and new, safer
equipment
ALL blood exposure or needle stick injuries should be reported and
appropriate action taken (see below)
Inoculation injuries
Inoculation injuries are the most likely route for transmission of blood-borne viral
infections.
Definition of inoculation injury
Includes all incidents where a contaminated object or substance breaches the
integrity of the skin or mucous membranes or comes into contact with the eyes.
Typical types:
Sticking or stabbing with a used needle or instrument
Splashes with contaminated substance top the eye or other open lesion
Cuts with contaminated equipment
Bites or scratches inflicted by patients
Treatment – inoculation injuries must be dealt with promptly
Injury
Allow wound to bleed (not scrubbed) and washed
thoroughly with running water, place waterproof dressing
Risk assessment including immune status of
„victim‟ +/- carrier status
Seek urgent advice according to the local arrangements re
follow up and whether serological surveillance is necessary
Every hospital will have at least one designated specialist eg
consultant microbiologist to contact re advice on postexposure prophylaxis
A full record of the incident should be recorded in the
accident / incident book.
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All dental practices and hospital dental and oral surgery departments should have an
incident book for recording a variety of incidents. In addition to this, surgeries and
departments should have local rules/protocols in place for the management of so
called „needle-stick‟ injuries. Such protocols reduce the risk of omissions in the
management of individuals and help ensure an accurate and contemporaneous
record of the incident is kept for current and future reference. The location of this
should be known by all staff and a „lead‟ clinician should be identified for reference.
In the situation described, the injured member of staff (victim for descriptive
purposes) should allow the injured site to bleed and the site should be washed
thoroughly with soap under running water. The site should not be scrubbed as this
may further disperse the contamination. The site should then be covered with a
waterproof plaster. The person should then report the incident immediately to the
„lead‟ individual so that the reporting and assessment process may begin. The name
of the injured party and their position should be recorded together with that of the
assessing individual should be recorded in the incident book. The time of the injury,
nature of injury, the anatomical site, and the location in the practice were the injury
occurred should be recorded. The nature of the injury is important. A penetrating
injury as recorded here represents a higher risk of infection transmission than a
scratch type injury for example.
The instrument itself should be examined as to its type and degree of contamination
(e.g. visible blood) – this should again be recorded. Different types of instruments
pose different risks. Solid instruments will represent a low risk to transmission. A
hollow instrument such as a needle will constitute a higher risk especially if there is
significant donor material present.
These components ie injury type and particulars of the instrument involved are
aspects of the risk assessment. The hepatitis B status of the victim should be
established (NB all clinical staff should be immunised against Hepatitis B and a
record of their current anti-HBs level should be kept up to date – currently the level
recommended to provide cover is >100mIU/ml). If possible the viral carrier status of
the source patient should be ascertained. The later may only be possible if the
source is known and requires seeking their expressed consent and liaison with local
occupational health departments.
Once a risk assessment has been performed if there is any concern in respect of
injury type, victim immunisation or status of source, urgent advice should be sort
from the local occupational health service. At this stage an incident form should be
completed.
Risk of acquiring HIV infection following an inoculation injury is small. If the injury is
assessed as significant for transmission of HIV based on the following:
1.
2.
3.
4.
Deep injury to the health care worker (implied but not specified in this essay)
Visible blood on the device causing injury
Device previously placed in patient‟s vein or artery
Source patient within last 60days of life (ie late stage AIDS)
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…and the source patient is HIV infected, the use of antiretroviral drugs taken
prophylactically ASAP after exposure (ideally within 1hour) is recommended. Postexposure prophylaxis (PEP) involves a short course (4weeks) of antiretroviral drug
treatment in an attempt to further reduce the risk of infection with HIV
References
1. Girdler N M, Hill C M, Sedation in Dentistry. Wright 1998
2. BD Medical Systems Intravenous Cannulation Training Programme
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