Fig. 4
From: Ultrasound-guided peripheral vascular catheterization in pediatric patients: a narrative review
Several technique options for confirming the needle tip in the short-axis out-of-plane (SAX-OOP) approach. a Tilting the probe back and forth along the travel direction of the catheter. b Sweeping the probe back and forth along the travel direction of the catheter. c The catheter can be moved back and forth while straddling the ultrasound plane when the operator does not want to move away from the best plane. The following are possible explanations of when the needle tip looks to be placed successfully into the vessel in the SAX-OOP approach, but no back flow is observed in the catheter hub. d When a strong reflector is in the side-lobe beam, the ultrasound machine mixes the reflected signals of the main and side-lobe beam, and structures these signals into the same ultrasound image (side-lobe artifact). e The ultrasound machine assumes that the emitted beam is extremely thin. However, the beam actually has a measurable thickness that varies with depth. Thus, when the needle tip and the vessel are in the same beam width, even if the needle tip is in the vessel, they are structured into the same ultrasound image (slice-thickness artifact)