High-frequency micro-ultrasound for vascular access in young children--a feasibility study by the High-frequency...

Cannulation of small arteries and veins in young children can be challenging. Although anesthesiologists frequently use ultrasound for placement of central venous lines and nerve blocks, its use for cannulation of small, peripheral vessels is less helpful. Ultrasound systems (7-15 MHz) currently used in clinical practice focus poorly at the sub-10-mm space and thus lack the resolution to allow accurate ultrasound-guided cannulation of small vessels. High-frequency micro-ultrasound (HFMU) is a new technology that allows higher resolution (15-50 MHz) compared with conventional ultrasound. Limited human studies have been performed thus far with HFMU, and none have been performed in young children or for vascular access.

This study was conducted to determine the feasibility of using HFMU to visualize and cannulate peripheral arteries and central veins in children under the age of 6 years old. The diameter of radial and ulnar arteries was also measured.

The anesthesiologists involved in this study found the 50 MHz HFMU probe useful for cannulation of peripheral arteries, especially in the youngest children. The higher-frequency probes were less helpful for internal jugular vein cannulation because it was not always possible to view the carotid artery while cannulating the vein.

The experience gained in this feasibility study suggests that HFMU could be a valuable addition to our armamentarium for difficult vascular access in the future.