Effects of Subcutaneously Infiltrated Nitroglycerin on Diameter, Palpability, Ease-of-Puncture, and Pre-Cannulation Spasm of the Radial Artery in Patients Undergoing Cardiac Surgery post radial angiography: A Randomized Controlled Trial

Radial artery cannulation is a critical procedure in cardiac surgery, providing vascular access for monitoring and intervention. However, this procedure is often complicated by factors such as small arterial diameter, reduced palpability, vasospasm, and difficulty in puncture, particularly in patients with a history of recent radial angiography where the radial artery is already punctured which may lead to vasospasm and endothelial dysfunction followed by complications like arterial remodeling altering the anatomy of the radial artery. These challenges can increase procedural failure rates, prolong operative time, and lead to patient discomfort. Effective pre-cannulation strategies are necessary to optimize arterial access and improve procedural success.

Nitroglycerin**, a well-known nitric oxide donor and potent vasodilator, has been widely used in cardiovascular medicine for its ability to relax vascular smooth muscle. Lignocaine(control) is a local anesthetic used commonly, which acts by inhibiting action potential by blocking sodium channel. Both the drugs are standard of care.** When administered subcutaneously, nitroglycerin may increase radial artery diameter, enhance arterial palpability, and reduce pre-cannulation spasm, potentially facilitating easier and more successful cannulation. Through a randomized controlled trial (RCT), we seek to determine whether this pharmacological approach can improve radial artery accessibility and procedural outcomes in this specific patient population.

The findings of this research could provide valuable insights into optimizing radial artery cannulation techniques, potentially leading to enhanced procedural efficiency, reduced complications, and improved patient outcomes in cardiac surgery.

 Novelty of the study - Unlike prior studies focusing on diagnostic or interventional coronary procedures, this study specifically evaluates patients undergoing cardiac surgery who have had prior radial angiography, a group at higher risk of arterial narrowing or spasm thereby hindering the radial artery cannulation, which is the knowledge gap addressed by this study since no previous research has been done in this particular cohort of patients. While intra-arterial and topical nitroglycerin have been studied for similar purposes, the effects of subcutaneous nitroglycerin infiltration specifically in cardiac patients undergoing surgery at least seven days post-radial angiography also remain, underexplored.