Arterial Line Management for Adult Patients

• Aims
• Background
• Procedure method (step by step)

Aims

To provide patients with robust evidence based  care
To provide practitioner with graded evidenced based procedures of care
To enable care to be audited in a meaningful manner

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Background and indications for standard operating procedure/protocol

Arterial Cannula are used for

• Blood pressure measurement
• Arterial blood sampling

Arterial cannulation allows for continuous blood pressure monitoring (the displayed waveform can be useful for diagnostic purposes) and repeated sampling, particularly for arterial blood gas analysis of PaO2, PaCO2 and acid base status.

Arterial pressure measurement does vary according to cannulation site used.

Radial and dorsalis pedis measurement is higher than femoral cannulation due to the greater distance travelled from the heart to the distal vessels and the smaller vessel lumen (Adams and Osbourne 1997).

The choice of site is made by the Practitioners inserting the cannula based on various factors.
Accepting the need for appropriate placement of cannula to meet the needs of disabled people or people with a specific medical condition, religious requirements e.g. symbols and taking into account rights under human rights legislation promoting dignity, respect and autonomy, especially where the patient does not have capacity to make a decision.

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Procedure method (step by step)

Consent
Wherever possible, informed consent should be obtained from the patient. When consent cannot be obtained it is assumed, as the procedure is regarded as necessary for the patients wellbeing. (In accordance with LTHT policy).

Cannula insertion
Insertion is carried out by competent clinical practitioners and medical staff under sterile conditions
http://nww.lhp.leedsth.nhs.uk/common/guidelines/detail.aspx?ID=537

Equipment required:

• Pressure bag
• 500/1000 ml bag of 0.9% sterile saline
• Cannula
• Dressing pack, sterile gloves
• 2% Chlorhexidine with 70% alcohol wipes
• Semi permeable transparent dressing
• Transducer kit (red arterial transducer set or dual CVP/Arterial transducer)
• Red needle free connector
• Syringes
• Local anaesthetic (Preferable)

On-going care of indwelling cannula and monitoring

Assess insertion site twice daily using the VIP score. Assessment includes site appearance, condition of distal limb (colour, temperature, pain).

Ask daily if the cannula is still required.

Arterial cannulas are only changed when clinically indicated (unexplained pyrexia, obvious site infection) (CDC 1996).

Dressing need only be changed if blood is present, if there is excessive moisture or if the dressing is loose, use a semi permeable transparent dressing. (Loveday et al, EPIC 3  2014). The area should be cleaned with chlorhexidine 2% in 70% isopropyl alcohol moving from the catheter site outwards (use alternative eg povidine iodine in 70% alcohol if patient has a history of chlorhexidine sensitivity (EPIC 3 2014).

Check transducer system each shift for fluid level and secure connections, re zero transducer once per 24hrs, keep inflated to 300mmHg. If in doubt over accuracy of BP reading correlate with NIBP.
The transducer must be positioned and zero’d to the phlebostatic axis which is at the intersection of the fourth intercostal space and the mid axillary line.

Every 96hrs, replace whole transducer set down to the arterial cannula hub or up to and including 3 way tap and red needle free connector. (A double transducer set is the one of choice if CVP monitoring is also required).
This is a two person aseptic procedure: one to occlude the artery and one to change the set.

No drugs are to be given via an arterial cannula. Inadvertent intra-arterial administration can lead to parasthesia, severe pain, motor dysfunction, compartment syndrome, gangrene and limb loss,  (Sen et al, 2005).
Check transducer fluid as part of shift checks - 0.9% Saline should be used - a glucose based product can have the potentially fatal risk of unrecognised hypoglycaemia as effects listed above.

Anti-embolic stocking must not be used when the dorsalis pedis site is in use, they can cause pressure on the cannula self.

When accessing transducer set to obtain blood, adhere to Aseptic Non Touch Technique (ANTT) and Personal Protective Equipment must always be used.  

Taking blood from a transduced  arterial cannula

This can only be done or supervised by a registered and competent practitioner using an Aseptic Non-Touch Technique (ANTT).

Check that arterial blood is required, if not then consider accessing blood via another line e.g. central line (this is often not possible in critical care due to administration of other drugs).

Equipment :
Gloves, plastic apron, pre-heparinised syringe, 2ml syringe x 2 ( a 5ml syringe may be needed in cardiac ICU due to the positioning of the 3 way tap on the transducer system), 2% Chlorhexidine in 70% alcohol wipes.

Removal of arterial cannula

Can only be performed or supervised by a registered and competent practitioner using ANTT.

• When?
• Sampling access or waveform monitoring is no longer required
• Signs of infection/inflammation.

It is recommended that the clotting status of the patient is known and documented prior to removal.

Adverse clotting times affect the length of time the practitioner will need to occlude the artery post cannula removal. Minimum occlusion time is 3 minutes.

Procedure

• Decontaminate hands as per LTHT Hand Hygiene policy.
• Switch alarms off on monitor.
• Decontaminate hands as per LTHT Hand Hygiene policy.
• Apply clean examination gloves and a disposable apron.
• Remove dressing.
• Remove cannula with a steady movement, keeping parallel to the skin. Apply pressure for at least 3 minutes. Check integrity of cannula before disposing - Only send cannula tips for M C & S if clinically indicated.
• When bleeding stopped apply semi-permeable occlusive dressing or plaster.
• Document VIP score, time and date of removal in patient documentation.

Post removal observations include:

• Colour, warmth and presence of pulse of limb.
• Checking for bleeding for the first hour after removal.
• Ask patient not to use the hand excessively for the first hour after removal.
• Avoid taking non-invasive BP on that arm for 12-24 hours to minimise bleeding.
• Inform shift coordinator or medical staff if bleeding occurs, haematoma develops, limb loses colour, or the patient complains of undue pain.
• If VIP score >1 continue to monitor and record daily until 0.