**3. Advantages and disadvantages of the different ultrasound-guided vascular access training models**

### **3.1 Blue Phantom®**

Commercially available simulator to be used as a training model of procedures in which ultrasounds are used as vascular access guides (**Figure 1**).

They are expensive, not-transportable, and not-changeable, although the latest models permit even simulate arterial pulse (**Figure 2**). The puncture needle entry point and path usually remain visible. The puncture performance sensation on this model is different from that on human tissues. They require maintenance and deteriorates after multiple puncture performances. They are not easily available nor affordable [21–23].

### **3.2 Silicone models**

Commercially available models consisting of a silicone model containing a tubular structure which permits the vascular access simulation and that can be refilled after each puncture performance. They have a long average life, and they are easily transportable. However, they offer a small surface area due to their small size, they are expensive and not easily available to all [11, 26, 27]. The puncture needle entry point and path remain visible after multiple puncture performances (**Figure 3**).

### **3.3 Agar/gelatine models**

It consists of an agar or gelatine model in which a tubular elastic structure is inserted (in some cases, Penrose surgical drains of different sizes). They have been used by radiologists to train and teach ultrasound-guided procedures (**Figure 4**). They are easy to construct by using everyday kitchen utensils and they are ideal for hand-eye coordination learning and improvement [28, 29].

However: (a) they usually show an uniform appearance of the ultrasound image (**Figure 5**) without identifiable muscle or tendon structures (with the exception of preparations including any component like mucilage); (b) the puncture needle

**Figure 1.** *Blue Phantom® model.*

**Figure 2.** *Ultrasound image of internal jugular vein and carotid artery (Blue Phantom® model).*

entry point and path remain visible after some puncture performances; (c) their puncture performance sensation is different from that on human tissues; (d) depending on the gelatine concentration used during their construction, they can be easily damaged, and; (e) the needle sideways movements during its introduction into the agar/gelatine could be hardly controllable when trying to puncture the vessel.

### **3.4 Animal models**

(a) "In vivo": the use of research animals results in high cost and laborious preparation when optimal conditions are required (sedation, mechanical ventilation or respiratory support, monitoring, etc.) as well as in a limited number of punctures; (b) "artificial": they are manually constructed by using pork, turkey or chicken thighs, pork-belly, tofu or sausage/cold meat piece as *muscle structure*, and different elastic components (urinary catheters, chest drains, metallic trocar, serum infusion systems, etc.) as *vascular structure*. By using them, a real sensation *Revision of Training Models on Ultrasound-Guided Vascular Access: Presentation of an Animal… DOI: http://dx.doi.org/10.5772/intechopen.101901*

**Figure 3.** *Silicone model for ultrasound-guided vascular access.*

**Figure 4.**

*Gelatine model: Penrose drains using different water-soluble colorants, which are fixed to different gelatine layers (image courtesy of Dr. Vicente Roqués).*

**Figure 5.** *Ultrasound image of transversal axis (left) and longitudinal axis (right) within the gelatine model.*

of different tissues is created with respect to both the ultrasound image perspective and the sensation obtained when performing puncture and cannulation/vascular access. These models show an affordable preparation, but their construction needs a certain amount of time. In addition, they are inexpensive as well as easily transportable and manageable. Their design permits different complexity levels with respect to different vessels diameter and depth, so the difficulty level can be increased as progress is made on the training process. With respect to their disadvantages, these models' conservation needs refrigeration, their average life is short (some weeks to get their muscle structure deteriorated) and they must be carefully constructed in order to reduce their risk of air introduction into their vascular structure [8, 15, 25].

The main advantages and disadvantages of the main cannulation-puncture models are shown in **Table 1**.
