Feasibility and placement accuracy of a sensor-guided intraosseous device with an automated stop in a small-bone rat...

Rapid intraosseous (IO) access is critical in emergency care when venous access is not feasible. IO access is particularly prone to error in small animals and human neonates with narrow medullary cavities. This pilot study evaluated the feasibility and placement accuracy of a novel sensor-guided IO drilling device with an automatic stop mechanism in a rat cadaver model.

Seven thawed Sprague-Dawley rat cadavers underwent 14 tibial insertions by a single experienced operator using a standardised protocol. Placement was assessed by computed tomography (CT), with successful insertion defined as intramedullary positioning of the needle tip. Two blinded readers independently classified each insertion. The principal outcome was the proportion of successful placements; a prespecified device-evaluable analysis excluding user-related targeting errors was exploratory.

Nine of 14 insertions were correctly positioned, yielding a success rate of 64.3% (9/14; 95% CI 35.1-87.2%). In the device-evaluable analysis, success was 81.8% (9/11; 95% CI 48.2-97.7%). Three lateral displacements and two overpenetrations occurred. Reader agreement was complete (κ = 1.00). The medullary cavity narrowed from 6.02 mm at the proximal metaphysis to 3.13 mm at the diaphysis, with cortical thickness of 0.54-0.57 mm; proximal epiphyseal outer diameter of 8.07 mm. No device malfunction was identified.

In this small-bone cadaver model, the automated-stop intraosseous device achieved CT-verified intramedullary placement in most attempts and functioned as intended. As this single-arm pilot lacked a comparator and CT assessed needle-tip position rather than functional access, the findings are limited to placement accuracy and are hypothesis-generating.