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3D Printing Design for Infants’ Medical Consumables
2.3. The 3D model printing of infant’s airway and small resistance. The soft inflatable cuff material

The 3D printing data came from DICOM files of CT is thermoplastic elastomer, which is a type of polymer
material with both rubber and thermoplastic properties. It
scan [18] . According to the growth and development rate exhibits high elasticity of rubber at room temperature and
of infants [19] , the DICOM files of airway CT scan of 7 can be plasticized at high temperature.
infants aged 30, 60, 90, 120, 180, 270, and 360 were
selected from the medical image database of Beijing 3. Results
Children’s Hospital. The slice thickness was 0.625mm
and the pixel spacing was 0.4883 mm. The model was 3.1. Correlations between the continuous numeric
set in the center of the printer platform. The settings data
were as follows: (i) Print nozzle diameter was set to 2
0.2 mm; (ii) print height was set to 0.1mm; (iii) the wall A single-level liner model showed a higher value in the R of
thickness was set to 2 mm; (iv) the bottom thickness was G-C (0.456 vs. 0.330), TD (0.206 vs. 0.175) and LD (0.170 vs.
set to 1 mm; (v) the filling density was set to 50%; (vi) 0.160) of the age, compared with the weight (Figure 5). The
2
print speed was 10.0mm/s; (vii) the nozzle temperature regression equation showed an R of 0.47, 0.23, and 0.19 in
was set to 20°C; (viii) the support type was set to floor the multivariate model of G-C, TD, and LD, respectively.
support; and (ix) the model size ratio was set to 1:1. With the log values of the predictors as shown in Table 1, age
The set slice file is saved in G-code format and printed. was a significant predictor of G-C (logworth 6.48, P < 0.05)
The printing material of convex models polylactic acid and TD (logworth 1.78, P < 0.05). However, weight was not
(PLA) with a diameter of 1.75 mm and fused deposition a significant predictor for all three models (logworth 0.13,
modeling (FDM) was used to obtain the required model. 0.37, and 0.423, P > 0.05) (Figure 5 and Table 1).
After printing, the model was processed by removing 3.2. The non-transparent convex and transparent
support, polishing, and smoothing. SLA laser curing concave 3D printing models of infant’s airway
layer printing was adopted in concave models printing,
the material was transparent resin, the printing resolution According to the growth and development rate of
was 0.01mm, and the molding speed was 100g/h [20,21] . infants [22,23] , the DICOM files of airway CT scan of seven
“Convex” is the 1:1 3D models of the external contour infants aged 30, 60, 90, 120, 180, 270, and 360 days were
of the infant’s airway, reflecting the actual size of the infant’s selected to print non-transparent convex and transparent
trachea and bronchi. Convex models can contribute to the concave 3D models (Figure 6).
design of the size and length of the inflatable cuff by more
accurately measuring the key dimensions and sizes of the 3.3. The important parameters for designing BB
infant’s convex airway models. “Concave” refers to the infants only from measuring convex 3D models
printing of the infant’s airway inner cavity which simulates and CT scan image
the real size of the infant’s trachea and bronchial cavity
structure, and is used to test and verify the compatibility The important parameters for designing BB infants only
between the new-style infant’s BB designed in this study were obtained from measuring convex 3D models and
and tracheobronchial inner cavity of infants. CT scan image. G-C (Distance from glottis to carina for
FDM printing (using PLA for convex models) is designing the location of barycenter on BB) is 70.347 ±
more economic and faster than SLA printing with highly 6.254 mm, TD (TD to match up with the diameter of the
transparent photosensitive resin. The most important role right main bronchus) is 5.189 ± 1.036 mm (n = 7). LD
of the convex model is to measure and to reflect the external (LD to match up with distance from upper margin of RUL
contour of the infant’s airway for research purposes. Using opening to carina) is 6.325 ± 1.725 mm (n = 7) and T-G
FDM printing helps save money and printing time [20,21] . (Distance between incisor teeth and glottis) is 44.580 ±
3.698 mm (n = 124) (Figure 7).
Nevertheless, SLA printing with highly transparent
photosensitive resin is used in the concave models to 3.4. The trial-produced sample of BB infants
enable a more direct view of the blocking state of the new- only in a concave 3D printing model
style BB inside the airway and to assess the sealing effect.
Therefore, it is worth spending more research, financial According to the important design parameters mentioned
support, and time on this printing model. above, the samples of BB infants only were successfully
This study had entrusted a qualified medical catheter trial-produced. In the sample, the inflatable cuff is
manufacturer (Shenzhen Medoo Medical Tech. Co., equipped with a LD of 6 mm and a TD of 5 mm. The
Shenzhen Guangdong, China) to produce trial-produced wall of cuff has the adaptability of 25% expansion to
BBs. The body of BBs catheter material is nylon 11 adjust to the individual differences of different infants.
with characteristics including light weight, corrosion Meanwhile, the barycenter of the BB should be 120 mm
resistance, not easy to fatigue cracking, good sealing, away from the distal end of the catheter (Figure 8).

34 International Journal of Bioprinting (2022)–Volume 8, Issue 3