Evaluation of tactile guidance cue mappings for emergency percutaneous needle insertion

In severe trauma cases, rare but fatal conditions may quickly arise, requiring immediate percutaneous needle insertion to save the patient. As there is no time to wait for experts, inexperienced individuals are required to perform these procedures, often leading to complications. We propose the design of a novel vibrotacile sleeve to guide users through this task. While realization of a robust closed-loop guidance system is far from complete, we begin this project by identifying and evaluating three major guidance cue mappings that could be used for our sleeve: (1) tool space (guiding needle orientation and insertion), (2) Cartesian space (guiding desired needle tip), and (3) joint space (guiding user elbow and wrist angles). In this paper, we aim to determine which of these mappings have the best performance in a simulated needle insertion task. We developed an adjustable sleeve consisting of a stretchable fabric with vibrotactile motors, affixed using hook-and-loop material. In a human subject study, we evaluated the effectiveness of these cues to elicit a series of desired movements (up, down, lateral motion, rotation, diagonal movement) by tracking the subject movements as they interacted with a haptic device. We found that tool space guidance mappings lead to significantly lower normalized direction error for both up/down and diagonal movements (p value <;0.0001). Users also rated tool space as the easiest mapping (1.87/5, SD= 0.75) and found that diagonal movements were the most difficult cues to understand.