Flow-mediated dilation facilitates radial artery cannulation in patients undergoing intravenous general anesthesia: A prospective randomized controlled trial

Background: Flow-mediated dilation (FMD) is commonly used as a diagnostic tool to assess endothelial function, and compared with other methods for stimulating radial artery dilation, FMD offers several advantages such as non-invasiveness, ease of execution, minimal equipment requirements, and negligible risk. The study aimed to investigate the effect of FMD in facilitating radial arterial cannulation in the context of intravenous general anesthesia. Methods: Eighty patients undergoing intravenous general anesthesia and requiring radial artery cannulation were randomized 1:1 to the FMD group and control group. Patients in the FMD group received an upper arm occlusion for 5 min after anesthesia induction, and the cuff was placed without inflation for the equivalent duration in the control group. The primary outcome was first-attempt success rate. Secondary outcomes were the diameter and percentage of dilation of radial artery, overall success rate, total number of attempts, cannulation time, and occurrence of procedure-related complications. Results: Intravenous anesthetic agents significantly dilated the radial artery (p < 0.05), which was further increased by FMD. An increase in both the first-attempt and overall success rate of radial artery cannulation was demonstrated with the use of FMD (67.5% vs 42.5%, p < 0.05). The total number of attempts needed to cannulate the radial artery was reduced in the FMD group as compared with the control group (p < 0.05), but no differences in cannulation time and procedure-related complications were found between the two groups (p > 0.05). Conclusions: FMD induced by a 5-min upper arm occlusion may facilitate radial artery cannulation in patients undergoing intravenous general anesthesia.