Caudal injectate can be reliably imaged using portable ultrasound – a preliminary study

BACKGROUND: Correct caudal cannula placement is essential for block success and the avoidance of complications. The aim of this study was to assess the use of a saline injection test bolus with ultrasound (US) imaging to identify correct cannula placement for caudal anesthesia. METHODS: A prospective observational study of 60 children undergoing caudal anesthesia. A Sonosite 180 Plus (Sonosite Inc., Bothwell, WA) was used to image the spine and look for caudal space expansion secondary to saline injection. RESULTS: Saline test bolus correctly identified position in 96.5% of all subjects, and was 100% successful in children under 2 years of age. CONCLUSIONS: These preliminary results suggest saline test bolus under US imaging is a reliable indicator of correct cannula position for caudal block. We found it safe, quick to perform, and provided additional useful information.