Effect of Subcutaneous Versus Topical Nitroglycerin on the Radial Artery Dimensions in Pediatric Patients Undergoing Surgery: A Randomized Non-inferiority Trial.

OBJECTIVES

To compare the changes in radial artery dimensions produced by subcutaneous nitroglycerin (NTG) versus a topical NTG patch in pediatric patients.

DESIGN

Randomized controlled non-inferiority trial.

SETTING

Pediatric and cardiac operating rooms at a tertiary care hospital.

PARTICIPANTS

Forty-five children aged 2 to 8 years undergoing surgery requiring radial arterial catheterization for hemodynamic monitoring or blood gas sampling.

INTERVENTIONS: Patients were randomized to receive either subcutaneous NTG (5 µg/kg diluted in 0.5 mL of saline solution, administered under ultrasound guidance) or a topical NTG patch (Releasing approximately 200 µg/h) applied over the radial artery 30 minutes before induction. Radial artery dimensions were measured ultrasonographically at baseline and after NTG administration.

MEASUREMENTS AND MAIN

RESULTS

The increase in post-intervention vertical diameter in the topical NTG group met the predefined criterion for non-inferiority when compared with the subcutaneous NTG group (non-inferiority margin, -0.3 mm). Compared with subcutaneous NTG, topical NTG produced a significantly greater percentage increase in vertical diameter (0.45% ± 11.76% v 15.6% ± 16.18%, p = 0.002), horizontal diameter (3.53% ± 16.01% v 19.72% ± 16.42%, p = 0.001), and cross-sectional area (3.6% ± 18.02% v 38.29% ± 26.65%, p < 0.001). Subcutaneous NTG resulted in a markedly greater increase in radial artery depth when compared with topical NTG (84.35% ± 47.09% v -0.37% ± 15.8%, p < 0.001). The first-attempt cannulation success rate was lower in the subcutaneous NTG group (81.8% v 100%, p = 0.049). No NTG-related adverse events or significant hemodynamic changes were observed in either group.

CONCLUSIONS

Topical NTG was statistically non-inferior to subcutaneous NTG in increasing the radial artery vertical diameter. Although the absolute post-intervention dimensions were similar between groups-likely influenced by the slightly smaller baseline arterial dimensions in the topical NTG group-the topical application produced larger percentage increases from baseline and did not cause the depth increase observed with subcutaneous NTG.