The effect of subcutaneous infiltration of nitroglycerin on the arterial cannulation under ultrasound guidance: a prospective randomized study

Background: Ultrasound (US) guidance has not improved the success rate of radial artery cannulation to nearly 100%. This explains the other factors that can be improved to increase the success rate. This study analyses the effect of subcutaneously infiltrated nitroglycerin on the first-attempt success rate of the US-guided short-axis method of radial artery cannulation. Patients and Methods: Two hundred and fourteen patients were randomized into two groups. In group N, 250 mcg nitroglycerin and 10 mg lignocaine were infiltrated subcutaneously at the cannulation site of the radial artery. Whereas in the control group (group S), the subjects received saline and 10 mg of lignocaine. The measured outcomes were the first-attempt success rate, cannulation time, and radial artery diameter changes. All cannulations were carried out with US guidance and employed the short-axis method. Results: One hundred and ninety-eight patients were analyzed. We found significant differences in both first-attempt success rates (P < 0.001) and decreased cannulation time (6.09 ± 2.08 vs. 3.33 ± 2.18 min, P < 0.001) in group N. The mean differences in the radial artery diameter were also significantly larger in group N at the puncture site (25.0 ± 19.5 vs. 1.9 ± 13.1 mm, P < 0.001) and at the radial fossa (23.1 ± 12.67 vs. 8.4 ± 6.5 mm, P < 0.001). Conclusion: Subcutaneous infiltration of nitroglycerin at the puncture site increases the first-attempt success rate of the US-guided short-axis method of radial arterial cannulation. Furthermore, it also decreases the cannulation time and increases the radial artery diameter