Bali Journal of Anesthesiology

: 2021  |  Volume : 5  |  Issue : 4  |  Page : 290--291

Non-traumatic “saline flush stylet” technique as an alternative rescue approach in difficult peripheral arterial catheter insertion

Mridul Dhar 
 Department of Anesthesiology and Critical Care, All India Institute of Medical Sciences, Rishikesh, Uttarakhand, India

Correspondence Address:
Dr. Mridul Dhar
Department of Anesthesiology and Critical Care, All India Institute of Medical Sciences, Rishikesh, Uttarakhand.

How to cite this article:
Dhar M. Non-traumatic “saline flush stylet” technique as an alternative rescue approach in difficult peripheral arterial catheter insertion.Bali J Anaesthesiol 2021;5:290-291

How to cite this URL:
Dhar M. Non-traumatic “saline flush stylet” technique as an alternative rescue approach in difficult peripheral arterial catheter insertion. Bali J Anaesthesiol [serial online] 2021 [cited 2022 Jun 28 ];5:290-291
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Invasive arterial blood pressure monitoring is an important tool in the armamentarium of the anesthesiologist, especially in cases with hemodynamic fluctuations or those requiring frequent arterial sampling for blood gas analysis. The technique of catheter threaded over a needle or a guidewire is an established practice for arterial catheter insertion. Numerous devices or types of catheters are commercially available for peripheral arterial cannulation such as Leader Cath (Vygon®, with guide wire), arterial switch cannulas, or routine peripheral intravenous cannulas which are quite commonly used, especially for short-term use.

Numerous studies on use of ultrasonography for peripheral arterial line insertion have shown higher first pass success rates, mostly related to vessel identification,[1],[2] but have inconclusive evidence of overall success rates,[3] indicating that problems may still be encountered while threading the catheter even after correct identification and needle entry. We often struggle in cases of initial failure to thread or if the vessel goes in to vasospasm. We then have to either wait for the spasm to decrease before trying again or attempt in another limb. Patients in intensive care units (ICUs) may have similar problems, due to them being on vasopressor agents or in shock, which may further decrease chances of first pass success.[4]

Two commonly used techniques for insertion are the anterior puncture technique (puncturing the anterior arterial wall at a more acute angle to thread the catheter directly over the needle) or the posterior puncture technique (puncturing both the anterior and posterior arterial walls at a lesser acute angle of around 45°, withdrawing till backflow is observed and then inserted into vessel).[2] Although not advised, we might need to switch the insertion strategy in case the stylet and catheter go through and through the vessel inadvertently in the anterior puncture approach [Figure 1]a. We suggest an alternative rescue approach at this point in the procedure wherein instead of using the same stylet to enter the vessel, we remove the stylet, fix the catheter in place, and attach a 5–10 mL syringe filled with heparinized saline (10 U/mL) [Figure 1]b. We then aspirate gently to confirm correct position [Figure 1]c and start pushing saline into the catheter, while simultaneously advancing it into the vessel. If the catheter moves in freely, check again by aspirating and push the catheter till the entire length while continuously and gently flushing saline [Figure 1]d. This will replace the splinting action of the stylet and prevent bending or buckling of the catheter to some extent, while insertion.[5] Alternatively, after removing stylet, the catheter can be withdrawn with the syringe attached, gently creating a negative aspirating outward force, similar to how it is aspirated while locating a central venous or arterial line till free flow of arterial blood is aspirated. The catheter can then be inserted into the vessel with the continuous saline flush as described earlier.{Figure 1}

Often after first attempt failure, it is very difficult to thread the catheter again in the same vessel. Using a guide wire can be another option as in the Leader-Cath. If not available, this technique of using the flush of saline as a “non-traumatic stylet” can be used to advance the catheter and increase chances of successful cannulation without further trauma to vessel wall. Saline flush has been used commonly to identify vessel entry as well as to facilitate insertion for peripheral venous cannulas, especially in pediatric patients.

We propose to emulate this in difficult or failed peripheral arterial cannulations in elective surgeries as well as in sick patients in ICUs. We have found initial success in this subset of cases and plan to conduct a randomized trial on the same. Although arterial line insertion is a technical procedure related to experience and the equipment at hand, this technique may be attempted as a rescue technique in situations of initial failed attempts.

 Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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 Conflicts of interest

There are no conflicts of interest.


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