Volume 26 · Issue 03 · 2023

The wound mechanism, injury characteristics and treatment principles of anti-armored vehicle ammunition against armored crew in the past 20 years are summarized in this paper. Shock vibration, metal jet, depleted uranium aerosol and post armor breaking effect are the main factors for wounding armored crew. Their prominent characteristics are severe injury, high incidence of bone fracture, high rate of depleted uranium injury, and high incidence of multiple/combined injuries. During the treatment, attention must be paid on that the space of armored vehicle is limited, and the casualties should be moved outside of the cabin for comprehensive treatment. Especially, the management of depleted uranium injury and burn/inhalation injury are more important than other injuries for the armored wounds.

SAM junctional tourniquet (SJT) has been applied to control junctional hemorrhage. However, there is limited information about its safety and efficacy when applied in the axilla. This study aims to investigate the effect of SJT on respiration when used in the axilla in a swine model.

Eighteen male Yorkshire swines, aged 6-month-old and weighing 55 - 72 kg, were randomized into 3 groups, with 6 in each. An axillary hemorrhage model was established by cutting a 2 mm transverse incision in the axillary artery. Hemorrhagic shock was induced by exsanguinating through the left carotid artery to achieve a controlled volume reduction of 30% of total blood volume. Vascular blocking bands were used to temporarily control axillary hemorrhage before SJT was applied. In Group I, the swine spontaneously breathed, while SJT was applied for 2 h with a pressure of 210 mmHg. In Group II, the swine were mechanically ventilated, and SJT was applied for the same duration and pressure as Group I. In Group III, the swine spontaneously breathed, but the axillary hemorrhage was controlled using vascular blocking bands without SJT compression. The amount of free blood loss was calculated in the axillary wound during the 2 h of hemostasis by SJT application or vascular blocking bands. After then, a temporary vascular shunt was performed in the 3 groups to achieve resuscitation. Pathophysiologic state of each swine was monitored for 1 h with an infusion of 400 mL of autologous whole blood and 500 mL of lactated ringer solution. T_b and T₀ represent the time points before and immediate after the 30% volume-controlled hemorrhagic shock, respectively. T₃₀, T₆₀, T₉₀ and T₁₂₀, denote 30, 60, 90, and 120 min after T₀ (hemostasis period), while T₁₅₀, and T₁₈₀ denote 150 and 180 min after T₀ (resuscitation period). The mean arterial pressure and heart rate were monitored through the right carotid artery catheter. Blood samples were collected at each time point for the analysis of blood gas, complete cell count, serum chemistry, standard coagulation tests, etc., and thromboelastography was conducted subsequently. Movement of the left hemidiaphragm was measured by ultrasonography at T_b and T₀ to assess respiration. Data were presented as mean ± standard deviation and analyzed using repeated measures of two-way analysis of variance with pairwise comparisons adjusted using the Bonferroni method. All statistical analyses were processed using GraphPad Prism software.

Compared to T_b, a statistically significant increase in the left hemidiaphragm movement at T₀ was observed in Groups I and II (both p < 0.001). In Group III, the left hemidiaphragm movement remained unchanged (p = 0.660). Compared to Group I, mechanical ventilation in Group II significantly alleviated the effect of SJT application on the left hemidiaphragm movement (p < 0.001). Blood pressure and heart rate rapidly increased at T₀ in all three groups. Respiratory arrest suddenly occurred in Group I after T₁₂₀, which required immediate manual respiratory assistance. PaO₂ in Group I decreased significantly at T₁₂₀, accompanied by an increase in PaCO₂ (both p < 0.001 vs. Groups II and III). Other biochemical metabolic changes were similar among groups. However, in all 3 groups, lactate and potassium increased immediately after 1 min of resuscitation concurrent with a drop in pH. The swine in Group I exhibited the most severe hyperkalemia and metabolic acidosis. The coagulation function test did not show statistically significant differences among three groups at any time point. However, D-dimer levels showed a more than 16-fold increase from T₁₂₀ to T₁₈₀ in all groups.

In the swine model, SJT is effective in controlling axillary hemorrhage during both spontaneous breathing and mechanical ventilation. Mechanical ventilation is found to alleviate the restrictive effect of SJT on thoracic movement without affecting hemostatic efficiency. Therefore, mechanical ventilation could be necessary before SJT removal.

High explosives are used to produce blast waves to study their biological effects. The lungs are considered as the critical target organ in blast-effect studies. The degree of lung hemorrhaging is related to both the explosive power and the increased lung weight. We studied the characteristics of the biological effects from an air explosion of a thermobaric bomb in a high-altitude environment and the lethality and lung injury severity of goats in different orientations and distances.

Goats were placed at 2.5, 3, 4, and 5 m from the explosion center and exposed them to an air blast at an altitude of 4700-meter. A group of them standing oriented to the right side and the other group seated facing the explosion center vertically. The lung injuries were quantified according to the percentage of surface area contused, and using the pathologic severity scale of lung blast injury (PSSLBI) to score the 4 injury categories (slight, moderate, serious and severe) as 1, 2, 3, and 4, respectively. The lung coefficient (lung weight [g]/body weight [kg]) was the indicator of pulmonary edema and was related to lung injury severity. Blast overpressure data were collected using blast test devices placed at matching locations to represent loadings to goats. All statistical analyses were performed using SPSS, version 26.0, statistical software (SPSS, Inc., Chicago, IL, USA).

In total, 127 goats were involved in this study. Right-side-standing goats had a significantly higher mortality rate than those seated vertical-facing (p < 0.05). At the 2.5 m distance, the goat mortality was nearly 100%, whereas at 5 m, all the goats survived. Lung injuries of the right-side-standing goats were 1 - 2 grades more serious than those of seated goats at the same distances, the scores of PSSLBI were significantly higher than the seated vertical-facing goats (p < 0.05). The lung coefficient of the right-side-standing goats were significantly higher than those of seated vertical-facing (p < 0.05). Mortality, PSSLBI, and the lung coefficient results indicated that the right-side-standing goats experienced severer injuries than the seated vertical-facing goats, and the injuries were lessened as the distance increased. The blast overpressure was consistent with these results.

The main killing factors of the thermobaric bomb in the high-altitude environment were blast overpressure, blast wind propulsions and burn. The orientation and distances of the goats significantly affected the blast injury severity. These results may provide a research basis for diagnosing, treating and protecting against injuries from thermobaric explosions.

Child head injury under impact scenarios (e.g. falls, vehicle crashes, etc.) is an important topic in the field of injury biomechanics. The head of piglet was commonly used as the surrogate to investigate the biomechanical response and mechanisms of pediatric head injuries because of the similar cellular structures and material properties. However, up to date, piglet head models with accurate geometry and material properties, which have been validated by impact experiments, are seldom. We aim to develop such a model for future research.

In this study, first, the detailed anatomical structures of the piglet head, including the skull, suture, brain, pia mater, dura mater, cerebrospinal fluid, scalp and soft tissue, were constructed based on CT scans. Then, a structured butterfly method was adopted to mesh the complex geometries of the piglet head to generate high-quality elements and each component was assigned corresponding constitutive material models. Finally, the guided drop tower tests were conducted and the force-time histories were ectracted to validate the piglet head finite element model.

Simulations were conducted on the developed finite element model under impact conditions and the simulation results were compared with the experimental data from the guided drop tower tests and the published literature. The average peak force and duration of the guide drop tower test were similar to that of the simulation, with an error below 10%. The inaccuracy was below 20%. The average peak force and duration reported in the literature were comparable to those of the simulation, with the exception of the duration for an impact energy of 11 J. The results showed that the model was capable to capture the response of the pig head.

This study can provide an effective tool for investigating child head injury mechanisms and protection strategies under impact loading conditions.

This study aims to elucidate the electrotaxis response of alveolar epithelial cells (AECs) in direct-current electric fields (EFs), explore the impact of EFs on the cell fate of AECs, and lay the foundation for future exploitation of EFs for the treatment of acute lung injury.

AECs were extracted from rat lung tissues using magnetic-activated cell sorting. To elucidate the electrotaxis responses of AECs, different voltages of EFs (0, 50, 100, and 200 mV/mm) were applied to two types of AECs, respectively. Cell migrations were recorded and trajectories were pooled to better demonstrate cellular activities through graphs. Cell directionality was calculated as the cosine value of the angle formed by the EF vector and cell migration. To further demonstrate the impact of EFs on the pulmonary tissue, the human bronchial epithelial cells transformed with Ad12-SV40 2B (BEAS-2B cells) were obtained and experimented under the same conditions as AECs. To determine the influence on cell fate, cells underwent electric stimulation were collected to perform Western blot analysis.

The successful separation and culturing of AECs were confirmed through immunofluorescence staining. Compared with the control, AECs in EFs demonstrated a significant directionality in a voltage-dependent way. In general, type I alveolar epithelial cells migrated faster than type II alveolar epithelial cells, and under EFs, these two types of cells exhibited different response threshold. For type II alveolar epithelial cells, only EFs at 200 mV/mm resulted a significant difference to the velocity, whereas for, EFs at both 100 mV/mm and 200 mV/mm gave rise to a significant difference. Western blotting suggested that EFs led to an increased expression of a AKT and myeloid leukemia 1 and a decreased expression of Bcl-2-associated X protein and Bcl-2-like protein 11.

EFs could guide and accelerate the directional migration of AECs and exert antiapoptotic effects, which indicated that EFs are important biophysical signals in the re-epithelialization of alveolar epithelium in lung injury.

Abdominal CT scan using oral and intravenous (IV) contrast is helpful in the diagnosis of intra-abdominal injuries. However, the use of oral and IV contrast delays the process of diagnosis and increases the risk of aspiration. It has also been shown that CT scan with IV contrast alone is as helpful as CT scan with oral and IV contrast and rectal CT scan in detecting abdominal injuries. Therefore, the present study aims to prospectively compare the diagnostic value of CT scan with oral and IV contrast versus CT scan with IV contrast alone in the diagnosis of blunt abdominal trauma (BAT).

Altogether 123 BAT patients, 60 (48.8%) women and 63 (51.2%) men with the mean age of (40.4 ± 18.7) years who referred to the emergency department of Imam Khomeini Educational and Medical Center in Sari, Iran (a tertiary trauma center in north of Iran) from November 2014 to March 2017 and underwent abdominal CT scans + laparotomy were investigated. Those with penetrating trauma or hemodynamically unstable patients were excluded. The participants were randomly allocated to two groups: abdominal CT scan with oral and IV contrast (n = 63) and CT scan with IV contrast alone (n = 60). No statistically significant difference was found between two groups regarding the hemodynamic parameters, age, gender, injury mechanisms (all p > 0.05). The results of CT scan were compared with that of laparotomy results. The collected data were recorded in SPSS version 22.0 for Windows. Quantitative data were presented as mean and SD.

The sensitivity and specificity of CT scan using oral and IV contrast in the diagnosis of BAT were estimated at 96.48 (95% CI: 90.73 - 99.92) and 92.67 (95% CI: 89.65 - 94.88), respectively; while CT scan with IV contrast alone achieved a comparable sensitivity and specificity of 96.6 (95% CI: 87.45 - 99,42 and 92.84 (95% CI: 89.88 - 95.00), respectively.

CT scan with IV contrast alone can be used to assess visceral injuries in BAT patients with normal hemodynamics to avoid diagnostic delay.

Static progressive stretch (SPS) can be applied to treat chronic joint stiffness. However, the impacts of subacute application of SPS to the distal lower limbs, where deep vein thrombosis (DVT) is common, on venous thromboembolism remain unclear. This study aims to explore the risk of venous thromboembolism events following subacute application of SPS.

A retrospective cohort study was conducted on patients diagnosed with DVT following a lower extremity orthopedic surgery before being transferred to the rehabilitation ward from May 2017 to May 2022. Patients with unilateral lower limb comminuted para-articular fractures, transferred to rehabilitation ward for further treatment within 3 weeks after operation, followed up more than 12 weeks since initial manual physiotherapy, and diagnosed DVT by ultrasound before rehabilitation course were included in the study. Patients with polytrauma, without evidence of previous peripheral vascular disease or incompetence, had medication for thrombosis treatment or prophylaxis before the operation, detected with paralysis due to nervous system impairment, infected after operation during the regime, or with acute progression of DVT were excluded. The included patients were randomized to the standard physiotherapy and the SPS integrated groups for observation. Associated DVT and pulmonary embolism data were collected during the physiotherapy course to compare the groups. SSPS 28.0 and GraphPad Prism 9 were used for data processing. A p < 0.05 was set significant difference.

In total of 154 patients with DVT participating in this study, 75 of them were treated with additional SPS for postoperative rehabilitation. The participants in the SPS group showed improved range of motion (12.3° ± 6.7°). However, in the SPS group, there was no difference in thrombosis volume between the start and termination (p = 0.106, p = 0.787, respectively), although difference was seen intra-therapy (p < 0.001). Contingency analysis revealed the pulmonary embolism incidence (OR = 0.703) in the SPS group compared to the mean physiotherapy.

The SPS technique is a safe and reliable option to prevent potential joint stiffness without aggravating the risk of distal DVT for postoperative patients suffering from relevant trauma.

Hip fractures among elderly patients are surgical emergencies. During COVID-19 pandemic time, many such patients could not be operated at early time because of the limitation of the medical resources, the risk of infection and redirection of medical attention to a severe infective health problem.

A search of electronic databases (PubMed, Medline, CINAHL, EMBASE and the Cochrane Central Register of Controlled Trials) with the keywords "COVID", "COVID-19", "SARS-COV-2", "Corona", "pandemic", "hip fracture", "trochanteric fracture" and "neck femur fracture" revealed 64 studies evaluating treatment of hip fracture in elderly patients during COVID-19 pandemic time. The 30-day mortality rate, inpatient mortality rate, critical care/special care need, readmission rate and complications rate in both groups were evaluated. Data were analyzed using Review Manager (RevMan) V.5.3.

After screening, 7 studies were identified that described the mortality and morbidity in hip fractures in both COVID-19 infected (COVID-19 + ) and non-infected (COVID-19 -) patients. There were significantly increased risks of 30-day mortality (32.23% COVID-19 + death vs. 8.85% COVID-19 - death) and inpatient mortality (29.33% vs. 2.62%) among COVID-19 + patients with odds ratio (OR) of 4.84 (95% CI: 3.13 - 7.47, p < 0.001) and 15.12 (95% CI: 6.12 - 37.37, p < 0.001), respectively. The COVID-19 + patients needed more critical care admission (OR = 5.08, 95% CI: 1.49 - 17.30, p < 0.009) and they remain admitted for a longer time in hospital (mean difference = 3.6, 95% CI: 1.74 - 5.45, p < 0.001); but there was no difference in readmission rate between these 2 groups. The risks of overall complications (OR = 17.22), development of pneumonia (OR = 22.25), and acute respiratory distress syndrome/acute respiratory failure (OR = 32.96) were significantly high among COVID-19 + patients compared to COVID-19 - patients.

There are increased risks of the 30-day mortality, inpatient mortality and critical care admission among hip fracture patients who are COVID-19 +. The chances of developing pneumonia and acute respiratory failure are more in COVID-19 + patients than in COVID-19 - patients.

For the treatment of an intertrochanteric fracture combined with femoral head necrosis in middle-age patients, it has been controversial whether to perform fracture reduction and fixation first then total hip replacement, or direct total hip replacement. We present a rare case of 53-year-old male patient suffered from bilateral intertrochanteric fracture caused by a road traffic injury. The patient had a history of femoral head necrosis for eight years, and the Harris score was 30. We performed total hip replacement with prolonged biologic shank prostheses for primary repair. One year after the surgery, nearly full range of motion was achieved without instability (active flexion angle of 110°, extension angle of 20°, adduction angle of 40°, abduction angle of 40°, internal rotation angle of 25°, and external rotation angle of 40°). The Harris score was 85. For the middle-aged patient with unstable intertrochanteric fractures and osteonecrosis of the femoral head, we can choose primary repair for concurrent bilateral intertrochanteric fracture and femoral head necrosis with prolonged shank biologic total hip replacement.