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

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) but not in the control group (P > .05 for both). Cephalic vein CSA was significantly different between groups at the second measurement (P < .05) but not at the first 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%.