**4. Animal model construction and description**

The training model described here consists of the following [8]:

### **4.1 Muscle component**

Piece of bird breast that can be acquired at any grocery store/shop and with the following approximated measures (length, width, height): 10 cm × 10 cm × 3 cm (**Figure 7**). Frozen poultry breast is preferably used; being defrosted in a refrigerator within 24 hours before performing the vascular punctures.

### **4.2 Vascular component**

Tubular structure made in elastic material (modeling balloon) filled with 10 ml of water with water-soluble colorant and sealed on both sides by using knots (**Figure 8**).

**Figure 6.** *Components of different puncture-localization models. Left: vascular-nodular structure. Right: tissue-muscle structure.*

Both components simulate the muscle and the vascular structures of pediatric patients. The development of this model is based on the introduction of an eight French thoracic drain together with its puncture trocar passing longitudinally through the muscle component and at different depth levels. This simulates the different depths at which vessels are located in children depending on their age and weight. After that, the trocar is retired, and the drain plastic piece remains inside the muscle structure. In the drain distal part, the elastic tubular structure distal end is sutured in the knot area. When pulling the drain in the opposite direction, the device stays inside the muscle structure and then, it is prepared to be visualized and cannulated in an ultrasound-guided manner in this experimental model (**Figure 9**).

A system of clamps fixed at different length permits the application of different tension values on the elastic structure. Depending on these different tension values, three different diameter ranges can be obtained, which are comparable to pediatric patients' vessels diameters. Thus, different ultrasound-guided vascular access difficulty levels can be obtained (**Figure 10**).

To perform puncture and cannulation, a 3-French and 11-cm-length catheter is used, with a 30-cm radiopaque guide and a 5.5-mm needle. Each unit of this model permits the performance of more than 100 punctures without resulting

*Revision of Training Models on Ultrasound-Guided Vascular Access: Presentation of an Animal… DOI: http://dx.doi.org/10.5772/intechopen.101901*

**Figure 7.** *Training model muscle component sizes.*

**Figure 8.**

*Vascular structure filling with water-soluble colorant, by using a syringe (left) or a dispenser (right).*

### **Figure 9.**

*Left: Puncture trocar passing longitudinally through the model muscle tissue. Middle: Drain suture on the side of the vascular structure which is isolated distal portion (details in the upper-right corner). Right: Placement of the vascular structure inside the muscle structure, and after the traction of the drain sutured to the vascular structure.*

**Figure 10.**

*Vessel's diameters (D1–D3) depending on the stretching degree of the elastic structure with its clamps (arrows) and their ultrasound representation.*

deteriorated at a cost of approximately 3 €. The model is replicable and reusable, and it lasts for approximately 6 hours at room temperature. When sessions last less than 6 hours, the model can be stored in an airtight container and refrigerated again. This increases its durability without affecting neither the visualization quality nor the puncture technique.

Ultrasound gel or aqueous solution (double-distilled water or saline 0.9%) are recommended to get a better visualization of the vascular structures.

By using a linear probe ultrasound machine, choosing the "preset vascular," and 2-cm depth, the vascular structure in the training model as well as its correlation with the real image "in vivo" in the patient can be observed (**Figure 11**).

After visualizing the vessel, the depth and diameter of the elastic tubular structure, which is similar to the pediatric patient's vessel, are determined.

*Revision of Training Models on Ultrasound-Guided Vascular Access: Presentation of an Animal… DOI: http://dx.doi.org/10.5772/intechopen.101901*

It can be stablished 3 depth levels and 3 diameter levels according to preliminary results from 300 depth and diameter measurements of the most common pediatric patients' central vessels. Within these data, different weights and sizes referenced by our group were found (**Table 2**). These measurements were valid with a 99% reliability.

The average values of these measurements are included within nine categories obtained by combining different vessels depths (three ranges) and diameters (three ranges) inside the muscular structure of the training model (**Table 3**).

The training model described permits to perform vessel puncture and cannulation in an ultrasound-guided manner in the three most used vascular-access ultrasound axes: transverse axis-out of plane, oblique axis-in plane, and longitudinal axis-in plane (**Figures 12**–**14**).

### **Figure 11.**

*Experimental training model image (left) with respect to the "in vivo" real image (right).*


### **Table 2.**

*Depth and diameter measurements (in centimeters: cm) of the main central vessels within the pediatric population (n = 300).*


### **Table 3.**

*Depth ranges (P1–3) and diameter ranges (D1–3) measured in centimeters (cm) used in the training model for ultrasound-guided vascular access.*

### **Figure 12.**

*Left: Puncture needle in the transverse axis-out of plane. Right: Vascular structure ultrasound image in the transverse axis-out of plane.*

### **Figure 13.** *Vascular visualization and image of the puncture needle in the oblique axis-in plane.*

**Figure 14.** *Vascular visualization and image of the puncture needle in the longitudinal axis-in plane.*

*Revision of Training Models on Ultrasound-Guided Vascular Access: Presentation of an Animal… DOI: http://dx.doi.org/10.5772/intechopen.101901*
