In Response to “A Modified ‘Over-the-Needle' Technique for Arterial Cannulation”

Abstract

I would like to comment on the letter to the editor from Koshy et al1Koshy T. Kumar P. Misra S. et al.A modified “over-the-needle” technique for arterial cannulation.J Cardiothorac Vasc Anesth. 2008; (in press)Google Scholar regarding a technique for arterial puncture in adult patients. Radial artery cannulation, in fact, can be difficult in cases involving small children; patients with hypotension, changes in cardiac output, or anatomic changes of the artery; and a lack of experience of the physician. The Seldinger technique may help specifically when the cannula cannot be advanced into the arterial lumen. However, this technique increases cost, and it does not solve the main problem, which is the puncture of the artery. Ultrasound is also of great help, but it is not always available. Several years ago, in this Journal, we published a letter to the editor regarding arterial punctures in small children.2Lema G. Urzua J. An aid for percutaneous arterial catherization in small children.J Cardiothorac Vasc Anesth. 1992; 6: 384-385Abstract Full Text PDF PubMed Scopus (3) Google Scholar We described a technique used already in several hundred patients with success. According to that technique, we fill the catheter needle with heparinized saline. As the cannula enters the artery, a small reddish color appears in the fluid, indicating the correct position of the cannula inside the artery. We also tested this procedure to see if it could be useful in any situation, and we found that the rapidity was clear only at low blood pressures, which makes it ideal for arterial punctures in small children and neonates. I doubt that the technique as described by Koshy et al may have any advantage in adults because the pressure is definitively higher, and in those cases the taint of the saline appears at the same time as the rise of blood in the needle. The only available sign in adults and older children (patients with high pressures) is the continuous rise of the blood column in the hub of the needle. A Modified “Over-the-Needle” Technique for Arterial CannulationJournal of Cardiothoracic and Vascular AnesthesiaVol. 23Issue 5PreviewThe radial artery is commonly cannulated percutaneously for invasive blood pressure monitoring because of its superficial location. The success of arterial cannulation is primarily dependent on the skill of the operator, which is acquired over a certain period of time. Despite this, failure to cannulate is not uncommon. This could either be because of the difficulty to enter the artery or because of the difficulty in threading the cannula into the artery once a flash of blood is seen on the hub of the cannula. Full-Text PDF