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Borràs-Novell, et al.
Since the current prototype was developed on a base the skin after removal) was added to the edge of the mask
and tested on the face of a mannequin, an ethical approval in contact with the manikin to optimize its adherence.
was not necessary and was therefore not sought from the The manikin was ventilated with non-invasive
ethics committee of our center. ventilator and the printed mask with adequate thoracic
excursion.
3. Results Since air leakage percentage was not displayed on
3.1. Image capture our neonatal non-invasive ventilators, we created a “leak-
free circuit” with an invasive ventilator. For this purpose,
The facial surface of the manikin was scanned with the manikin leaks were blocked with a plasticine mold in
a 3D Peel 2 CAD scanner, as shown in Figure 1. The the mouth and printed mask was connected to inspiratory
manikin was placed in a supine position, in an incubator and expiratory tubing. Under the same conditions, with
with a sliding mattress and with three spatial reference a constant flow of air, invasive ventilator measured 78%
points. The procedure lasted 10 min, with a direct light to of air leakage from standardized mask, and 64% from
manikin’s eyes in 1.5 – 2 min. individualized mask.
For evaluating how the mask was fitted to the
3.2. Image processing manikin’s face, we marked with ink the edges of both
We use Mimics Medical 24.0 program from Materialize masks. We fitted both mask to two manikin’s face prints
(approved for designing medical and surgical devices for during 30 s. Pressure distribution is shown in Figure 4.
medical use) to customize a mask that perfectly fits the We estimated that the whole process might involve
geometry of the manikin with smooth contact boundaries. 6 h and cost 80 euros. This price also accounted for the
The customized mask was designed to rest on the nasal time spent by the team of engineers, who designed the
bone, nasolabial sulcus and philtrum, without contacting prototype and made the subsequent corrections under
the alas of the nose nor obstructing the nostrils. In medical criteria, and the materials used.
the manikin that was used to design the prototype of
customized mask, its size would correspond to the XS–S A B
size of commercial masks. The work related to image
processing and subsequent design corrections under
medical guidelines lasted 2 h (Figure 2).
3.3. 3D printing
The created design was sent for printing. The process
of printing the mask with selected biocompatible and
hypoallergenic silicone (AMSil™ Silbione™ 24501-
50 TRS A-B) took 3 h and consumed about 2 g of the
material. The first mask obtained, as shown in Figure 3,
had no macroscopic defects. An adhesive silicone strip
type Silbione RTGel 4642 A&B (which does not damage
Figure 2. (A) Customized mask design. (B) Comparison of the
contact surface with the standardized mask (in orange) and with
the customized mask (in blue).

A B

Figure 3. (A) Checking the fit of printed nasal mask on the face of
the manikin (B) checking the adherence of printed nasal mask to
Figure 1. Scan of the facial surface of the manikin. the face (without subjection system).

International Journal of Bioprinting (2022)–Volume 8, Issue 2 27