Subcutaneous nitroglycerin increased the success rate of radial artery cannulation in women with gestational hypertension undergoing cesarean section : A randomized controlled trial.

Background: Radial artery cannulation helps to maintain the stability of maternal hemodynamics and reduce complications; however, it is difficult for women with gestational hypertension. Subcutaneous nitroglycerin was found to improve the first attempt success rate of radial artery cannulation in pediatric patients. Therefore, this study evaluated the effect of subcutaneous nitroglycerin on the radial artery diameter and area, blood flow rate and the success rate of radial artery cannulation in women with pregnancy-induced hypertension.

Methods: A total of 94 women with gestational hypertension and risk of intraoperative bleeding undergoing cesarean section were identified and randomized into the subcutaneous nitroglycerin group and control group. The primary outcome was the success rate of left radial artery cannulation within 3 min after subcutaneous injecting (T2). The puncture time, number of attempts, the overall complications, and ultrasonographic measurements including radial artery diameter, cross-sectional area and depth were also recorded before subcutaneous injection (T1), 3 min after subcutaneous injection (T2) and immediately after radial artery cannulation (T3).

Results: The first attempt success rate of radial artery cannulation was significantly higher (97.9% vs. 76.6%, p = 0.004) and procedure time to success was significantly shorter (111 ± 18 s vs. 171 ± 70 s, p < 0.001) in the subcutaneous nitroglycerin group as compared to the control group. The subcutaneous nitroglycerin group also had a significantly less overall number of attempts as 1/2/3 attempts (n), 46/1/0 vs. 36/7/4 (p = 0.008). Compared with the control group, the diameter and cross-sectional area of radial artery increased significantly at the T2 and T3 points in the subcutaneous nitroglycerin group (p < 0.001), as well as percentage change of radial artery diameter and CSA. Vasospasm (6.4% vs. 31.9%; p = 0.003) was significantly lower in the subcutaneous nitroglycerin group; however, no difference was found in hematoma (2.1% vs. 12.8%; p = 0.111).

Conclusion: Subcutaneous nitroglycerin along with the routine local anesthetic preparation before radial artery cannulation increased the first attempt success rate of radial artery cannulation and decreased the overall number of cannulation attempts in women with gestational hypertension and risks of intraoperative bleeding undergoing cesarean section, it also decreased cannulation times and overall number of vasospasms.