Background and aims Umbilical artery cannulation is a common neonatal procedure that is often challenging because umbilical arteries constrict after birth. We aimed to determine whether the topical application of a vasodilating ointment prior to cannulation increases success and decreases the time taken to cannulate.

Methods Discarded umbilical cords were collected immediately after delivery and two 3 cm sections proximal to the baby were used for the study. 0.1mL topical Glyceryl Trinitrate (GTN) ointment (0.2% w/w) was applied to the surface of one section for 5 min prior to cannulation, whereas the second section acted as the control. After ointment removal, medical staff blinded to intervention attempted to cannulate one artery in each section. We assessed cannulation success, time to cannulate, and correct treatment identification for each participant.

Results 14 experienced (9 Fellows, 5 Consultants) and 9 junior (Registrars) medical staff attempted 46 cannulations. Experienced participants successfully cannulated 100% of treated and control sections with no significant difference in mean (SD) time to cannulate (98 (75)s and 97(51)s respectively, p = 0.97). Junior participants cannulated 89% and 67% of treated and control sections respectively (p = 0.69), and mean (SD) time to cannulate was 132 (78)s and 106 (53)s respectively (p = 0.42). GTN treated arteries were correctly identified by 43% of experienced and 22% of junior participants (p = 0.47).

Conclusions This study suggests that topical application of GTN does not increase successful cannulation of umbilical arteries by experienced staff. More participants or prolonged GTN application time may be needed to confirm these findings in junior staff.