What is the proper technique for inserting an intravascular cannula into fragile peripheral veins?

From the Guidelines

To insert an intravascular cannula into fragile veins, use a small-gauge catheter (22-24G) and consider using ultrasound guidance, as it significantly improves success rates with difficult veins by allowing visualization of vein depth and direction. When inserting the cannula, begin by thoroughly assessing the patient's veins, selecting a straight, visible vein in the forearm if possible. Warm the insertion site with a warm compress for 5-10 minutes to improve vasodilation, as recommended by guidelines for safe vascular access 1. Position the limb below heart level to enhance venous filling. Clean the site with chlorhexidine 2% in 70% alcohol and allow it to dry completely. Stabilize the vein by applying gentle traction on the skin below the insertion point. Insert the cannula at a 10-15 degree angle (shallower than usual) and reduce the angle further once flashback occurs. Advance the catheter slowly and gently, never forcing it if resistance is met. After successful insertion, secure the cannula with a transparent dressing and minimize manipulation.

Some key considerations when inserting intravascular cannulae into fragile veins include:

• Using the smallest practical size of cannula, as recommended by the Association of Anaesthetists of Great Britain and Ireland 1
• Avoiding insertion in a limb with lymphoedema, except in acute situations, due to increased risks of local infection 1
• Considering the use of transillumination, ultrasound, and infra-red devices to aid in insertion, as these may be useful in difficult cases 1
• Avoiding repeated attempts in the same area and considering alternative sites like the dorsum of the hand or forearm, to preserve vein integrity and minimize complications. The use of ultrasound guidance is supported by evidence from studies on ultrasound-guided vascular access, which demonstrate improved success rates and reduced complications compared to traditional landmark-based techniques 1.

From the Research

Insertion Techniques for Intravascular Cannula into Fragile Veins

To insert an intravascular cannula into fragile veins, several techniques and guidelines can be followed:

• Use of ultrasound guidance for vascular access procedures, as recommended by 2, can increase the success rate of cannulation and reduce the risk of complications.
• Real-time ultrasound guidance with a high-frequency linear transducer is recommended for central venous catheter (CVC) insertion, regardless of the provider's level of experience 2.
• For peripheral venous access, real-time ultrasound guidance can be used to reduce the total procedure time, needle insertion attempts, and needle redirections 2, 3.
• The use of echogenic needles, plastic needle guides, and/or ultrasound beam steering can also increase the success rate of ultrasound-guided vascular access procedures 2.
• A standardized procedure checklist that includes the use of real-time ultrasound guidance can reduce the risk of central line-associated bloodstream infection (CLABSI) from CVC insertion 2.

Preprocedural Evaluation and Planning

Before inserting an intravascular cannula into fragile veins, the following steps can be taken:

• Evaluate the target blood vessel size and depth during preprocedural ultrasound evaluation 2.
• Use two-dimensional ultrasound to evaluate for anatomical variations and absence of vascular thrombosis during preprocedural site selection 2.
• Assess the distance from skin to vein and select the appropriate catheter length 3.
• Choose the optimal insertion angle and technique (out-of-plane or in-plane) for cannulation 3.

Operator Training and Competency

To ensure safe and successful insertion of intravascular cannula into fragile veins, operators should:

• Complete a systematic training program that includes a combination of simulation-based practice, supervised insertion on patients, and evaluation by an expert operator 2, 4.
• Demonstrate minimal competence before placing ultrasound-guided CVCs independently, with a minimum number of CVC insertions and a proctored assessment of competence 2.
• Participate in periodic refresher training sessions and competency assessments to maintain proficiency 2, 4.