Effects of Local Warming on the Peripheral Vein Cross-Sectional Area in Children Under Sedation

Abstract Purpose Peripheral venous catheterization is challenging in small children. The local warming technique has been used to increase the peripheral vein cross-sectional area (CSA) and improve the success rate. However, there is limited evidence on the effect of local warming on venous CSA in children under sedation. Design A pilot randomized controlled trial. Methods Eligible children aged 1 to 4 years undergoing ambulatory surgery were enrolled. At the bedside in the ambulatory surgery center, they were routinely sedated with 1 mcg/kg of intranasal dexmedetomidine. Through a computer allocation program, children were randomized into either a control group or a local warming group. Cephalic vein and basilic vein at 1 cm proximal to cubital fossa were scanned with ultrasound to measure venous CSA. Children in the control group received no intervention; those in the local warming group had a prepared hot pack of ~40°C applied to the target area on the arm for 5 minutes. A second ultrasound measurement was undertaken in both groups. Findings A total of 35 from 40 children were analyzed. Cephalic vein CSA and basilic vein CSA increased significantly vs the first measurement within the local warming group (P .05 for both). Cephalic vein CSA was significantly different between groups at the second measurement (P .05). Basilic vein CSA was significantly different between groups neither at the first measurement nor at the second measurement (P > .05 for both). The application of local warming resulted in an average of 34% increase (from 4.1 to 5.5 mm2) in cephalic vein CSA and an average of 21% increase (from 4.8 to 5.8 mm2) in basilic vein CSA. Conclusions The application of local warming induced mild venodilation in cephalic vein with an increase in CSA by 34% and had little venodilation effect on the basilic vein with an increase in CSA by only 21%.