In this month's clinical skills article, best practice for the insertion of a peripheral intravenous cannula (PIVC) will be discussed. An overview of equipment used, indications, complications and technique for PIVC will be discussed, with cognisance to an evidence-based approach to best practice technique. Critique of the anatomy and physiology of blood vessels; the process for aseptic non-touch-technique (ANTT) and the variety of intravenous cannulae available on the market will not be explored due to the overview focus of this article.
Safe patient care
The importance of appropriate and timely clinical interventions such as PIVC is, when required, paramount for safe patient care. PIVC is noted as being an important clinical intervention in paramedic practice (Banerjee et al, 2011). Clinical practice guidelines recommend a variety of medications be administered via the intravenous route (Joint Royal Colleges Ambulance Liaison Committee (JRCALC), 2017). Therefore, having the knowledge, skills and understanding of clinical conditions and presentations, in addition to the paramedic drug formulary, requires sound clinical judgement and justifiable decision-making to ensure appropriate interpretation of guidelines is undertaken to meet patient needs.
PIVC insertion sites
The recommended site for PIVC is the upper limb—specifically the anti-cubital fossae (ACF) (median cubital vein); the wrist (cephalic or basilic veins) or the back of the hand (metacarpal/dorsal arch) (Gregory and Mursell, 2010; O'Grady et al, 2011; Royal College of Nursing (RCN), 2016), with the median cubital vein being the preferred choice in an emergency (Gregory and Mursell, 2010; RCN, 2016). First attempts for PIVC should be at the most distal veins possible (RCN, 2016), with subsequent attempts proximal to prevent the potential for infiltration at previous sites (McGowan, 2014). Furthermore, there should be a maximum of two attempts due to a deteriorating success rate noted with subsequent efforts (Nadler et al, 2015).
However, in certain patient presentations such as cardiac arrest or the convulsing patient, further attempts may be justified, or other sites of insertion may need to be used, such as the external jugular vein or lower limbs (Gregory and Mursell, 2010; Thomas and Monaghan, 2014; RCN, 2016). The external jugular vein can be a useful alternative site of insertion for a PIVC; however, according to a study by Lahtinen et al (2009), the first-time success rate of placing an external jugular IV cannula is less than the antecubital veins in emergency situations. Nevertheless, the external jugular site may be justified owing to its proximity to the heart and the speed at which drugs and fluids are distributed throughout the body (Lahtinen et al, 2009).
Benefits vs. risks
Clinicians must always seek local guidance for use of the external jugular route. The use of lower limbs for PIVC carries a greater risk of thrombosis than upper limbs; therefore, the paramedic may be justified if the benefits outweigh the risks. If inserting a PIVC in the upper limb, specifically in the ACF, care should be taken to insert just above or below the fold of the antecubital area in an attempt to reduce the risk of discomfort when the patient flexes his or her arm. Furthermore, opting for this location goes some way towards minimising the complication of kinking the cannula, and the potential for mechanical phlebitis (Alexandrou et al, 2011; RCN, 2016).
Common and specific risks and complications include (Dougherty and Lister, 2015; RCN, 2016):
Choosing the correct vein
All blood vessels have nerve innervation from the sympathetic branch of the autonomic nervous system, creating ‘vasomotor tone’ and relative vaso/venoconstriction (Tortora and Derrickson, 2017). Overcoming this vasoconstriction results in a more palpable vein which can be achieved by gently palpating, lightly tapping or stroking the vein directly over the site of insertion to produce a release of histamine, which causes relative vasodilation (Dougherty and Lister, 2015). However, ‘smacking a vein’ can have the opposite effect by causing vasoconstriction and vasospasm due to the innervation of both pressure receptors and nociceptors (Koutoukidis et al, 2017). An additional method of venous engorgement includes placing a tourniquet approximately 6–8 inches proximal to the insertion site (Dougherty and Lister, 2015). Tourniquets must be single-use only owing to the risk of cross-infection and should easily be released with one hand (Weinstein and Hagle, 2014).
Ideally, the vein of choice should be identified according to Table 1. The choice of vein may also be determined by the patient's anatomy, clinical condition, the purpose of the cannula or whether further procedures determine the need for specific areas that need to be avoided; e.g. primary percutaneous coronary intervention, whereby the right or left wrist or forearm may need to be avoided. This may differ according to local guidelines and protocols.
| Veins to choose | Veins to avoid |
|---|---|
| Straight | Inflamed |
| Not overlying a joint (to reduce the risk of mechanical phlebitis) | Bruised |
| Soft | Thrombosed |
| Spongy | Feel hard when palpated or are located near bony prominences |
| Palpable | Previous multiple puncture sites |
| *Free from valves | Sites of infection |
| Sites of previous surgery |
Choosing cannula size
When choosing the correct size of cannula, it is important to consider its purpose. The largest cannulae, 14-16 gauge, should be used for rapid infusions of viscous fluids such as blood. Medium-to-smaller sizes, 18–20 gauge, are appropriate for infusion of crystalloid fluids and drugs. The smallest cannulae, 20–24 gauge, may be of sufficient size for the administration of drugs and are suitable for children (Waitt et al, 2004). Ideally, the smallest cannula that can possibly be used for the intended treatment should be used (Dougherty, 2008).
Cleaning the site
Clinicians should follow local and national guidance for best practice in cleansing the site of insertion.
Clinical indications
Clinical indications for cannula use are:
* Dependent on local guidance and scope of practice
**Prophylactic PIVC needs to be justified and based on sound clinical reasoning and judgement dependent on individual patient needs. The author suggests the following clinical conditions that may require prophylactic IV cannulation in paramedic practice:
It must be noted that in the time-critical patient, PIVC must not delay rapid transport to an appropriate healthcare facility (JRCALC, 2017).
Contraindications
It is important to note contraindications of cannula use (Waitt et al, 2004):
Performing the procedure
Conclusion
The skill of inserting a PIVC remains an important clinical intervention in paramedic practice and may be a lifesaving technique in managing a critically ill or injured patient. However, for safe and appropriate insertion of a PIVC, paramedics must be aware of its indications, contraindications, risks, and complications. Paramedics must also be able to justify their decision to perform PIVC if questioned.