Page 81 - JSOM Winter 2021

FIGURE 2 Computed tomography image of pulmonary contusion TABLE 1 Baseline Data
(A) and segmented contusion volume (B), as well as graph of Baseline Hemodynamic and Metabolic Data
pulmonary contusion volumes (C), and a representative pulmonary
contusion with laceration (D). 20% 30% 40%
Parameter Hemorrhage Hemorrhage Hemorrhage p Value
Heart rate, 101 ± 57 101 ± 34 87 ± 9 .829
bpm
Mean arterial
pressure, 74 ± 2 82 ± 20 81 ± 19 .745
mmHg
Cardiac
output, L/min 5.1 ± 1.9 5.5 ± 0.02 5.3 ± 0.9 .913
Potassium,
mmol/L 4.4 ± 0.8 4.4 ± 0 4.5 ± 0.1 .945
Lactate, 1.7 ± 0.9 1.8 ± 0.1 2.8 ± 0.9 .380
mmol/L

Survival
Kaplan-Meier analysis demonstrated 100% mortality at 12
and 115 minutes in the 40% and 30% hemorrhage groups,
respectively (Figure 3). There was 50% mortality at 3 hours in
the 20% hemorrhage group.

FIGURE 3 Kaplan-Meier survival analysis of the polytrauma model
involving three different hemorrhage volumes: 20%, 30%, and 40%
of total blood volume.

Statistical Analysis
We performed data analysis using Prism (GraphPad, https://
www.graphpad.com/) version 8. We present data using mean
± standard deviation. We assessed survival from end of trauma
using Kaplan-Meier analysis. We used analysis of variance to
compare hemodynamic and metabolic data among animals.
We considered a p-value of less than .05 significant.

Results
Pulmonary Contusion Dose-Finding
We enrolled six animals for pulmonary contusion dose-find-
ing. No animals were excluded from the study. The mean
weight was 67 ± 4 kg. Pulmonary contusion volumes for three,
six, and nine nonpenetrating captive bolt gun discharges were
24 ± 28, 50 ± 31, and 63 ± 77 cm , respectively (p = .679)
3
(Figure 2C). All animals with six or greater nonpenetrating
captive bolt gun applications also had a lacerative component Hemodynamic Data
to their pulmonary injury (Figure 2D). Only one of the two We compared hemodynamic data during trauma and hemor-
animals (50%) who received three nonpenetrating captive bolt rhage, as well as during the observation period across the three
gun applications had a lacerative component to their injury. groups (Figure 4). During trauma and hemorrhage, the 20%,
We selected six nonpenetrating captive bolt gun discharges for 30%, and 40% hemorrhage groups had a mean heart rate of
the polytrauma model as it reliably generated a pulmonary 119 ± 71, 169 ± 31, and 149 ± 59 bpm (p = .140), respec-
contusion with a lacerative component that was most consis- tively. The mean MAPs were significantly different at 66 ± 20,
tent between animals. 51 ± 2, and 40 ± 4mmHg (p = .040), as were the mean cardiac
outputs: 3.9 ± 0.9, 1.9 ± 0.1, and 1.4 ± 0.5 L/min (p = .016).
Evaluation of Polytrauma Model
We enrolled six animals for evaluation of the polytrauma During the observation period, the 20%, 30%, and 40% hem-
model with varying hemorrhage volumes: 20%, 30%, and orrhage groups had a mean heart rate of 148 ± 39, 121 ± 31,
40% of total blood volume. No animals were excluded. Mean and 31 ± 22 (p = .020), respectively. The mean MAPs were
weight was 69 ± 3 kg. Baseline hemodynamic and metabolic 51 ± 32, 24 ± 6, and 8 ± 1mmHg (p = .030), and the mean
data was comparable between animals and is presented in cardiac outputs were 5.2 ± 4.0, 1.1 ± 0.2, and 0.1 ± 0.2 L/min
Table 1. (p = .080).

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