FIGURE 2.

Photographs of the of the NGT interface showing correct needle angle relative to the beam for IP approach (A) and correction based on the NGT solid-to-dotted green lines, indicating that the operator should alter needle position relative to the beam. Needle guidance technology can help anesthesiologists recognize common technique issues that occur when the angle is inadvertently altered by ergonomic issues, operator fatigue, or inadvertent movement of the transducer (B). The needle segment in the beam is represented by a solid green line, and calculated positions of anterior and posterior segments are represented by dotted green lines. The NGT interface aids in visualizing needle position relative to the beam cross section (A, B: left). The corresponding appearance of the needle IP and OOP relative to the linear array probe is demonstrated in the diagram (C).