Page 91 - JSOM Winter 2023

FIGURE 2 Ukrainian model 3D-printed tourniquet. pressure transducer (Vernier Go Direct gas pressure sensor;
Vernier, https://www.vernier.com/) was wirelessly connected to
a computer with the corresponding software (Vernier Graphi-
cal Analysis, https://www.vernier.com/) to monitor and record
pressure data. The software was set to measure absolute pres-
sure (mmHg) once every second for 120 minutes.

Statistical Analyses
Pressure data were downloaded from the transducer’s propri-
etary software as CSV files and collected in Microsoft Excel for
Mac (version 16.69.1). Statistical testing was then conducted
using Python (version 3.8.5), including the Pandas (version

1.5.3) and Pinguine (version 0.5.3) packages. 14,15 Next, plots

were produced using Python and statistical data visualization
packages MatPlotLib (version 3.3.2) and Seaborn (Version
0.11.0). 16, 17

The data were examined for normality of distribution using
the Shapiro-Wilk test and a quantile-quantile plot. Levene’s
test was performed to assess homogeneity of variance. There-
after, a Kruskal-Wallis nonparametric test was performed, with
the Dunn post-hoc test with Bonferroni correction. Statistical
significance was set at p<.05 and data presented as mean and
standard deviation (SD). The p-values are given when p<.10.

Results
Environmental data were monitored continuously during the
trials, with a mean air temperature of 21.8°C (SD 0.6°C) and
Setup a mean humidity of 34.1% (SD 2.2%).
Using a method similar to several other studies, the tourniquets
were prepared with a neonatal blood pressure cuff filled with The Kruskal-Wallis test revealed a significant differences in
30 mL of air and attached to the patient side of the tourni- pressure drop between the tourniquets (p<.05). Post-hoc test-
quet strap. 4,10,13 The blood pressure cuff was connected to a gas ing revealed a significant difference between the CAT tour-
pressure sensor system using a 20-cm section of noncompress- niquet and the Ukraine tourniquet (p=.004). The difference
ible tubing from an arterial transducer set (XTrans, https:// between the SOF tourniquet and the Ukraine tourniquet was
www.codancompanies.com/), including a three-way connector not significant (p=.08). A box plot visualized the difference
(Baxter International Inc., https://www.baxter.com/). The gas (Figure 3).

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on l egressi nes
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100
FIGURE 3 Box plot with 80
pressure drop during
120-minute period for
three different types of
tourniquets. 60
rop (mmH ressure D P g))
40

20
1050 1075 100 1 12 15 1 150 175 1 1200 1225 1250
ressure S
tart (mmH
g) P
3D-Printed Tourniquets in Ukraine | 89