Pulmonary contusion: an update on recent advances in clinical management

High positive end-expiratory pressure ventilation mitigates the progression from unilateral pulmonary contusion to ARDS: An animal study

BACKGROUND

Pulmonary contusion (PC) is common in severely traumatized patients and can lead to respiratory failure requiring mechanical ventilation (MV). Ventilator-induced lung injury (VILI) might aggravate lung damage. Despite underrepresentation of trauma patients in trials on lung-protective MV, results are extrapolated to these patients, potentially disregarding important pathophysiological differences.

METHODS

Three MV protocols with different positive end-expiratory pressure (PEEP) levels: ARDSnetwork lower PEEP (ARDSnet-low), ARDSnetwork higher PEEP (ARDSnet-high), and open lung concept (OLC) were applied in swine for 24 hours following PC. Gas exchange, lung mechanics, quantitative computed tomography, and diffuse alveolar damage (DAD) score were analyzed. Results are given as median (interquartile range) at 24 hours. Statistical testing was performed using general linear models (group effect) over all measurement points and pairwise Mann-Whitney U tests for DAD.

RESULTS

There were significant differences between groups: PEEP ( p < 0.0001) ARDSnet-low (8 [8-10] cmH 2 O), ARDSnet-high (12 [12-12] cmH 2 O), OLC (21 [20-22] cmH 2 O). The fraction of arterial partial pressure of oxygen and inspired oxygen fraction ( p = 0.0016) was lowest in ARDSnet-low (78 (73-111) mm Hg) compared with ARDSnet-high (375 (365-423) mm Hg) and OLC (499 (430-523) mm Hg). The end-expiratory lung volume (EELV) differed significantly ( p < 0.0001), with highest values in OLC (64% [60-70%]) and lowest in ARDSnet-low (34% [24-37%]). Costa's surrogate for mechanical power differed significantly ( p < 0.0001), with lowest values for ARDSnet-high (73 [58-76]) compared with OLC (105 [108-116]). Diffuse alveolar damage was lower in ARDSnet-high compared with ARDSnet-low (0.0007).

CONCLUSION

Progression to ARDS, 24 hours after PC, was mitigated by OLC and ARDSnet-high. Both concepts restored EELV. ARDSnet-high had the lowest mechanical power surrogate and DAD. Our data suggest, that ARDSnet-high restored oxygenation and functional lung volume and reduced physiological and histological surrogates for VILI. ARDSnet-low generated unfavorable outcomes, such as loss of EELV, increased mechanical power and DAD after PC in swine. The high respiratory rate in the OLC may blunt favorable effects of lung recruitment.

Timing matters: Early versus late rib fixation in patients with multiple rib fractures and pulmonary contusion

BACKGROUND

Recent literature has shown that surgical stabilization of rib fractures benefits patients with rib fractures accompanied by pulmonary contusion; however, the impact of timing on surgical stabilization of rib fractures in this patient population remains unexplored. We aimed to compare early versus late surgical stabilization of rib fractures in patients with traumatic rib fractures and concurrent pulmonary contusion.

METHODS

We selected all adult patients with isolated blunt chest trauma, multiple rib fractures, and pulmonary contusion undergoing early (<72 hours) versus late surgical stabilization of rib fractures (≥72 hours) using the American College of Surgeons Trauma Quality Improvement Program 2016 to 2020. Propensity score matching was performed to adjust for patient, injury, and hospital characteristics. Our outcomes were hospital length of stay, acute respiratory distress syndrome, unplanned intubation, ventilator days, unplanned intensive care unit admission, intensive care unit length of stay, tracheostomy rates, and mortality. We then performed sub-group analyses for patients with major or minor pulmonary contusion.

RESULTS

We included 2,839 patients, of whom 1,520 (53.5%) underwent early surgical stabilization of rib fractures. After propensity score matching, 1,096 well-balanced pairs were formed. Early surgical stabilization of rib fractures was associated with a decrease in hospital length of stay (9 vs 13 days; P < .001), decreased intensive care unit length of stay (5 vs 7 days; P < .001), and lower rates of unplanned intubation (7.4% vs 11.4%; P = .001), unplanned intensive care unit admission (4.2% vs 105%, P < .001), and tracheostomy (8.4% vs 12.4%; P = .002). Similar results were also found in the subgroup analyses for patients with major or minor pulmonary contusion.

CONCLUSION

These findings suggest that in patients with multiple rib fractures and pulmonary contusion, the early implementation of surgical stabilization of rib fractures could be beneficial regardless of the severity of pulmonary contusion.

Evolution of Pulmonary Contusions in Patients With Severe Rib Fractures: Cause for Concern?

INTRODUCTION

The progression of pulmonary contusions remains poorly understood. This study aimed to measure the radiographic change in pulmonary contusions over time and evaluate the association of the radiographic change with clinical outcomes and surgical stabilization of rib fractures (SSRF).

METHODS

This retrospective cohort study included adults admitted with three or more displaced rib fractures or flail segment on trauma CT and when a chest CT was repeated within one week after trauma. Radiographic severity of pulmonary contusions was assessed using the Blunt Pulmonary Contusion Score (BPC18). Logistic regression was performed to evaluate the relation between SSRF and worsening contusions on repeat CT, adjusted for potential confounders.

RESULTS

Of 231 patients, 56 (24%) had a repeat CT scan. Of these, 55 (98%) had pulmonary contusion on the first CT scan with a median BPC18 score of 5 (P25-P75 3-7). Repeat CTs showed an overall decrease of the median BPC18 score to 4 (P25-P75 2-6, P = .02), but demonstrated a worsening of the pulmonary contusion in 16 patients (29%). All repeat CTs conducted within 12 hours post-injury demonstrated increasing BPC18. Radiographic worsening of pulmonary contusions was not associated with SSRF, nor with worse respiratory outcomes or intensive care length of stay, compared to patients with radiographically stable or improving contusions.

DISCUSSION

In patients with severe rib fracture patterns who undergo repeat imaging, pulmonary contusions are prevalent and become radiographically worse within at least the first 12 hours after injury. No association between radiographic worsening and clinical outcomes was found.

Experimental study of a novel mouse model of tibial shaft fracture combined with blunt chest trauma

BACKGROUD

Thoracic Trauma and Limb Fractures Are the Two most Common Injuries in Multiple Trauma. However, there Is Still a Lack of Mouse Models of Trauma Combining Tibial Shaft Fracture (TSF) and Thoracic Trauma. In this Study, we Attempted to Develop a Novel Mouse Model of TSF Combined with Blunt Chest Trauma (BCT).

METHODS

A total of 84 C57BL/6J male mice were used as the multiple trauma model. BCT was induced by hitting the chests of mice with heavy objects, and TSF was induced by hitting the tibia of mice with heavy objects after intramedullary fixation. Serum specimens of mice were received by cardiac puncture at defined time points of 0, 6, 12, 24, 48, and 72 h.

RESULTS

Body weight and body temperature tended to decrease within 24 h after multiple trauma. Hemoglobin analyses revealed a decrease during the first 24 h after multiple trauma. Some animals died by cardiac puncture immediately after chest trauma. These animals exhibited the most severe pulmonary contusion and hemorrhage. The level of lung damage varied in diverse mice but was apparent in all animals. Classic hematoxylin and eosin (H&E)-stained paraffin pulmonary sections of mice with multiple trauma displayed hemorrhage and an immunoinflammatory reaction. Bronchoalveolar lavage fluid (BALF) and serum samples of mice with multiple trauma showed an upregulation of interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-1α (TNF-1α) compared with the control group. Microimaging confirmed the presence of a tibia fracture and pulmonary contusion.

CONCLUSIONS

The novel mouse multiple trauma model established in this study is a common trauma model that shows similar pathological mechanisms and imaging characteristics in patients with multiple injuries. This study is useful for determining whether blockade or intervention of the cytokine response is beneficial for the treatment of patients with multiple trauma. Further research is needed in the future.

Association between lung contusion volume and acute changes in fibrinogen levels: A single-center observational study

Aim

Organ tissue damage, including the lungs, may lead to acute coagulopathy. This study aimed to evaluate the association between lung contusion volume and serum fibrinogen level during the acute phase of trauma.

Methods

We conducted an observational study using electronic medical records at a tertiary-care center between January 2015 and December 2018. We included patients with lung contusions on hospital arrival. We used three-dimensional computed tomography to calculate lung contusion volumes. The primary outcome was the lowest fibrinogen level measured within 24 h of hospital arrival. We evaluated the association between lung contusion volume and outcome with multivariable linear regression analysis. Also, we calculated the sensitivity and specificity of lung contusion volume in patients with a serum fibrinogen level of ≤150 mg/dL.

Results

We identified 124 eligible patients. Their median age was 43.5 years, and 101 were male (81.5%). The median lung contusion volume was 10.9%. The median lowest fibrinogen level within 24 h from arrival was 188.0 mg/dL. After adjustment, lung contusion volume had a statistically significant association with the lowest fibrinogen level within 24 h from arrival (coefficient -1.6, 95% confidence interval -3.16 to -0.07). When a lung contusion volume of 20% was used as the cutoff, the sensitivity and specificity to identify fibrinogen depletion were 0.27 and 0.95, respectively.

Conclusion

Lung contusion volume was associated with the lowest fibrinogen level measured within 24 h from hospital arrival. Measuring lung contusion volume may help to identify patients with a progression of fibrinogen depletion.

[Bilateral thoracic trauma-"double the trouble"?]

BACKGROUND

Thoracic trauma is associated with a high morbidity and mortality. Assessing the risk for complications is essential for planning the further treatment strategies and managing resources in thoracic trauma.

OBJECTIVE

The aim of the study was to analyze concomitant injuries in unilateral and bilateral rib fractures and pulmonary contusions and evaluate differences in complication rates between the two.

MATERIAL AND METHODS

In a retrospective study, data from all patients diagnosed with thoracic trauma at a level I trauma center were analyzed. Bivariate and multivariate analysis were used to examine an association of unilateral or bilateral rib fractures, serial rib fractures, and pulmonary contusions with multiple injuries and outcomes. In addition, multivariate regression analysis was utilized to determine the impact of age, gender and additional injuries on outcome.

RESULTS

A total of 714 patients were included in the analysis. The mean Injury Severity Score (ISS) was 19. Patients with an additional thoracic spine injury had a significantly higher incidence of bilateral rib fractures. Pulmonary contusions were associated with younger age. Abdominal injuries were predictors for bilateral pulmonary contusions. Complications occurred in 36% of the patients. Bilateral injuries increased the complication rate up to 70%. Pelvic and abdominal injuries as well as the need for a chest drain were significant risk factors for complications. The mortality rate was 10%, with higher age, head and pelvic injuries as predictors.

CONCLUSION

Patients with bilateral chest trauma had an increased incidence of complications and a higher mortality rate. Bilateral injuries and significant risk factors must therefore be considered. Injury of the thoracic spine should be excluded in those patients.

High risk and low prevalence diseases: Blast injuries

INTRODUCTION

Blast injury is a unique condition that carries a high rate of morbidity and mortality, often with mixed penetrating and blunt injuries.

OBJECTIVE

This review highlights the pearls and pitfalls of blast injuries, including presentation, diagnosis, and management in the emergency department (ED) based on current evidence.

DISCUSSION

Explosions may impact multiple organ systems through several mechanisms. Patients with suspected blast injury and multisystem trauma require a systematic evaluation and resuscitation, as well as investigation for injuries specific to blast injuries. Blast injuries most commonly affect air-filled organs but can also result in severe cardiac and brain injury. Understanding blast injury patterns and presentations is essential to avoid misdiagnosis and balance treatment of competing interests of patients with polytrauma. Management of blast victims can also be further complicated by burns, crush injury, resource limitation, and wound infection. Given the significant morbidity and mortality associated with blast injury, identification of various injury patterns and appropriate management are essential.

CONCLUSIONS

An understanding of blast injuries can assist emergency clinicians in diagnosing and managing this potentially deadly disease.

Pulmonary contusion: automated deep learning-based quantitative visualization

PURPOSE

Rapid automated CT volumetry of pulmonary contusion may predict progression to Acute Respiratory Distress Syndrome (ARDS) and help guide early clinical management in at-risk trauma patients. This study aims to train and validate state-of-the-art deep learning models to quantify pulmonary contusion as a percentage of total lung volume (Lung Contusion Index, or auto-LCI) and assess the relationship between auto-LCI and relevant clinical outcomes.

METHODS

302 adult patients (age ≥ 18) with pulmonary contusion were retrospectively identified from reports between 2016 and 2021. nnU-Net was trained on manual contusion and whole-lung segmentations. Point-of-care candidate variables for multivariate regression included oxygen saturation, heart rate, and systolic blood pressure on admission. Logistic regression was used to assess ARDS risk, and Cox proportional hazards models were used to determine differences in ICU length of stay and mechanical ventilation time.

RESULTS

Mean Volume Similarity Index and mean Dice scores were 0.82 and 0.67. Interclass correlation coefficient and Pearson r between ground-truth and predicted volumes were 0.90 and 0.91. 38 (14%) patients developed ARDS. In bivariate analysis, auto-LCI was associated with ARDS (p < 0.001), ICU admission (p < 0.001), and need for mechanical ventilation (p < 0.001). In multivariate analyses, auto-LCI was associated with ARDS (p = 0.04), longer length of stay in the ICU (p = 0.02) and longer time on mechanical ventilation (p = 0.04). AUC of multivariate regression to predict ARDS using auto-LCI and clinical variables was 0.70 while AUC using auto-LCI alone was 0.68.

CONCLUSION

Increasing auto-LCI values corresponded with increased risk of ARDS, longer ICU admissions, and longer periods of mechanical ventilation.

Watch Out for the Early Killers: Imaging Diagnosis of Thoracic Trauma

Radiologists and trauma surgeons should monitor for early killers among patients with thoracic trauma, such as tension pneumothorax, tracheobronchial injuries, flail chest, aortic injury, mediastinal hematomas, and severe pulmonary parenchymal injury. With the advent of cutting-edge technology, rapid volumetric computed tomography of the chest has become the most definitive diagnostic tool for establishing or excluding thoracic trauma. With the notion of "time is life" at emergency settings, radiologists must find ways to shorten the turnaround time of reports. One way to interpret chest findings is to use a systemic approach, as advocated in this study. Our interpretation of chest findings for thoracic trauma follows the acronym "ABC-Please" in which "A" stands for abnormal air, "B" stands for abnormal bones, "C" stands for abnormal cardiovascular system, and "P" in "Please" stands for abnormal pulmonary parenchyma and vessels. In the future, utilizing an artificial intelligence software can be an alternative, which can highlight significant findings as "warm zones" on the heatmap and can re-prioritize important examinations at the top of the reading list for radiologists to expedite the final reports.

Impact of flail chest injury on morbidity and outcome: ten years' experience at a tertiary care hospital in a developing country

BACKGROUND

One of the worst types of severe chest injuries seen by clinicians is flail chest. This study aims to measure the overall mortality rate among flail chest patients and then to correlate mortality with several demographic, pathologic, and management factors.

METHODOLOGY

A retrospective observational study tracked a total of 376 flail chest patients admitted to the emergency intensive care unit (EICU) and surgical intensive care unit (SICU) at Zagazig University over 120 months. The main outcome measurement was overall mortality. The secondary outcomes were the association of age and sex, concomitant head injury, lung and cardiac contusions, the onset of mechanical ventilation (MV) and chest tubes insertion, the length of mechanical ventilation and ICU stay in days, injury severity score (ISS), associated surgeries, pneumonia, sepsis, the implication of standard fluid therapy and steroid therapy, and the systemic and regional analgesia, with the overall mortality rates.

RESULTS

The mortality rate was 19.9% overall. The shorter onset of MV and chest tube insertion, and the longer ICU, and hospital length of stay were noted in the mortality group compared with the survived group (P-value less than 0.05). Concomitant head injuries, associated surgeries, pneumonia, pneumothorax, sepsis, lung and myocardial contusion, standard fluid therapy, and steroid therapy were significantly correlated with mortality (P-value less than 0.05). MV had no statistically significant effect on mortality. Regional analgesia (58.8%) had a significantly higher survival rate than intravenous fentanyl infusion (41.2%). In multivariate analysis, sepsis, concomitant head injury, and high ISS were independent predictors for mortality [OR (95% CI) = 568.98 (19.49-16613.52), 6.86 (2.86-16.49), and 1.19 (1.09-1.30), respectively].

CONCLUSION

The current report recorded mortality of 19.9% between flail chest injury patients. Sepsis, concomitant head injury, and higher ISS are the independent risk factors for mortality when associated with flail chest injury. Considering restricted fluid management strategy and regional analgesia may help better outcome for flail chest injury patients.

Trivial Blunt Chest Trauma Leading to Acute Respiratory Distress Syndrome in a Child

Both blunt and penetrating chest trauma in children are less common than in adults but cause severe acute morbidity and mortality. As the literature suggests, pulmonary contusion is the most common chest injury in children, occurring in more than half of all blunt chest trauma cases. Even patients with blunt injuries are likely to have a longer hospital stay. The difference in physiological and anatomical variations in children compared to adults makes it more difficult from the diagnosis, management, and monitoring perspectives. A thorough physical examination is needed with close clinical monitoring, and additional vigilance is important during the management of a child. The physiologic consequences, such as the dreaded complication of alveolar hemorrhage and pulmonary parenchymal destruction, usually manifest within a few hours of the trauma and can take up to seven days to recover. Hence, timely diagnosis is crucial during the emergency evaluation. The clinical diagnosis can be supported by a special imaging modality in the form of chest computed tomography (CT), which confirms the radiological parenchymal destruction with high sensitivity. Management is mostly supportive to start with and includes high-flow oxygen, ventilatory pressure support as needed for the severity of acute lung injury (ALI) or acute respiratory distress syndrome (ARDS), judicious fluid administration, control of the pain associated with bony and thoracic soft tissue injuries, and careful hemodynamic monitoring for other complications and sequelae likely to develop. Here, we report an interesting case of a 10-year-old male child presenting to the Pediatric Emergency Department with acute moderate-to-severe respiratory distress that developed after two days of a few vomiting episodes along with non-specific lower chest and substernal pain following blunt trauma to the chest. The injury was trivial in nature as described by the father caused by an accidental fall on a small pile of bricks while playing near his home. After triaging under the red category, the child was managed in line with acute respiratory distress. We ruled out pneumothorax, hemorrhagic pleural effusion or pericardial effusion, and other evidence of invasive chest as well as gross abdominal injuries by comprehensive but focused history and clinical examinations, including adjuncts such as point-of-care ultrasound) and chest X-ray (CXR). Although the initial arterial blood gas analyses were suggestive of a mild form of ARDS or ALI by the criteria based on the P:F ratio (PaO2 to FiO2 ratio, which was between 200 and 300 for the case), the CXR and the chest CT revealed that the child had significant lung parenchymal injury in the form of bilateral fluffy pulmonary infiltrates. This case indicates that even a trivial blunt trauma can induce certain mechanisms of lung injury, leading to severe manifestations and sometimes fatal complications such as pulmonary contusion, hemorrhage, and ARDS.

[Pathophysiology, Diagnostics and Therapy of Pulmonary Contusion - Recommendations of the Interdisciplinary Group on Thoracic Trauma of the Section NIS of the German Society for Trauma Surgery (DGU) and the German Society for Thoracic Surgery (DGT)]

Pulmonary contusion usually occurs in combination with other injuries and is indicative of a high level of force. Especially in multiply injured patients, pulmonary contusions are frequently detected. The injury is characterised by dynamic development, which might result in difficulties in recognising the actual extent of the injury at an early stage. Subsequently, correct classification of the extent of injury and appropriate initiation of therapeutic steps are essential to achieve the best possible outcome. The main goal of all therapeutic measures is to preserve lung function as best as possible and to avoid associated complications such as the development of pneumonia or Acute Respiratory Distress Syndrome (ARDS).The present report from the interdisciplinary working group "Chest Trauma" of the German Society for Trauma Surgery (DGU) and the German Society for Thoracic Surgery (DGT) includes an extensive literature review on the background, diagnosis and treatment of pulmonary contusion. Without exception, papers with a low level of evidence were included due to the lack of studies with large cohorts of patients or randomised controlled studies. Thus, the recommendations given in the present article correspond to a consensus of the aforementioned interdisciplinary working group.Computed tomography (CT) of the chest is recommended for initial diagnosis; the extent of pulmonary contusion correlates with the incidence and severity of complications. A conventional chest X-ray may initially underestimate the injury, but is useful during short-term follow-up.Therapy for pulmonary contusion is multimodal and symptom-based. In particular, intensive care therapy with lung-protective ventilation and patient positioning are key factors of treatment. In addition to invasive ventilation, non-invasive ventilation should be considered if the patient's comorbidities and compliance allows this. Furthermore, depending on the extent of the lung injury and the general patient's condition, ECMO therapy may be considered as an ultima ratio. In particular, this should only be performed at specialised hospitals, which is why patient assignment or anticipation of early transfer of the patient should be anticipated at an early time during the course.

Extracorporeal membrane oxygenation in traumatic brain injury - A retrospective, multicenter cohort study

INTRODUCTION

Patients with traumatic brain injury (TBI) regularly require intensive care with prolonged invasive ventilation. Consequently, these patients are at increased risk of pulmonary failure, potentially requiring extracorporeal membrane oxygenation (ECMO). The aim of this work was to provide an overview of ECMO treatment in TBI patients based upon data captured into the TraumaRegister DGU® (TR-DGU).

METHODS

A retrospective multi-center cohort analysis of patients registered in the TR-DGU was conducted. Adult patients with relevant TBI (AIS_Head ≥3) who had been treated in German, Austrian, or Swiss level I or II trauma centers using ECMO therapy between 2015 and 2019 were included. A multivariable logistic regression analysis was used to identify risk factors for the need for ECMO treatment.

RESULTS

12,247 patients fulfilled the inclusion criteria. The overall rate of ECMO treatment was 1.1% (134 patients). Patients on ECMO had an overall hospital mortality rate of 38% (51/134 patients) while 13% (1523/12,113 patients) of TBI patients without ECMO therapy died. Male gender (p = 0.014), AIS_Chest 3+ (p<0.001), higher Injury Severity Score (p<0.001) and packed red blood cell (pRBC) transfusion (p<0.001) were associated with ECMO treatment.

CONCLUSION

ECMO therapy is a potentially lifesaving modality for the treatment of moderate-to-severe TBI when combined with severe chest trauma and pulmonary failure. The in-hospital mortality is increased in this high-risk population, but the majority of patients is surviving.

Rib fixation in patients with severe rib fractures and pulmonary contusions: Is it safe?

BACKGROUND

Pulmonary contusion has been considered a contraindication to surgical stabilization of rib fractures (SSRFs). This study aimed to evaluate the association between pulmonary contusion severity and outcomes after SSRF. We hypothesized that outcomes would be worse in patients who undergo SSRF compared with nonoperative management, in presence of varying severity of pulmonary contusions.

METHODS

This retrospective cohort study included adults with three or more displaced rib fractures or flail segment. Patients were divided into those who underwent SSRF versus those managed nonoperatively. Severity of pulmonary contusions was assessed using the Blunt Pulmonary Contusion 18 (BPC18) score. Outcomes (pneumonia, tracheostomy, mechanical ventilation days, intensive care unit (ICU) length of stay, hospital length of stay, mortality) were retrieved from patients' medical records. Comparisons were made using Fisher's exact and Kruskal-Wallis tests, and correction for potential confounding was done with regression analyses.

RESULTS

A total of 221 patients were included; SSRF was performed in 148 (67%). Demographics and chest injury patterns were similar in SSRF and nonoperatively managed patients. Surgical stabilization of rib fracture patients had less frequent head and abdominal/pelvic injuries ( p = 0.017 and p = 0.003). Higher BPC18 score was associated with worse outcomes in both groups. When adjusted for ISS, the ICU stay was shorter (adjusted β , -2.511 [95% confidence interval, -4.87 to -0.16]) in patients with mild contusions who underwent SSRF versus nonoperative patients. In patients with moderate contusions, those who underwent SSRF had fewer ventilator days (adjusted β , -5.19 [95% confidence interval, -10.2 to -0.17]). For severe pulmonary contusions, outcomes did not differ between SSRF and nonoperative management.

CONCLUSION

In patients with severe rib fracture patterns, higher BPC18 score is associated with worse respiratory outcomes and longer ICU and hospital admission duration. The presence of pulmonary contusions is not associated with worse SSRF outcomes, and SSRF is associated with better outcomes for patients with mild to moderate pulmonary contusions.

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level IV.

Blunt thoracic trauma: role of chest radiography and comparison with CT - findings and literature review

In the setting of acute trauma where identification of critical injuries is time-sensitive, a portable chest radiograph is broadly accepted as an initial diagnostic test for identifying benign and life-threatening pathologies and guiding further imaging and interventions. This article describes chest radiographic findings associated with various injuries resulting from blunt chest trauma and compares the efficacy of the chest radiograph in these settings with computed tomography (CT). Common chest radiographic findings in blunt thoracic injuries will be reviewed to improve radiologic identification, expedite management, and improve trauma morbidity and mortality. This article discusses demographic information, mechanism of specific injuries, common imaging findings, imaging pearls, and pitfalls and exhibits several classic imaging findings in blunt chest trauma. Thoracic structures commonly injured in blunt trauma that will be discussed in this article include vasculature structures (aortic trauma), the heart (cardiac contusion, pericardial effusion), the esophagus (esophageal perforation), pleural space and airways (pneumothorax, hemothorax, bronchial injury), lungs (pulmonary contusion), the diaphragm (diaphragmatic rupture), and the chest wall (flail chest). Chest radiography plays an important role in the initial evaluation of blunt chest trauma. While CT imaging has a higher sensitivity than chest radiography, it remains a valuable tool due to its ability to provide rapid diagnostic information in time-sensitive trauma situations and is ubiquitously available in the trauma bay. Familiarity with the gamut of injuries that may occur as well as identification of the associated chest radiograph findings can aid in timely diagnoses and prompt management in the setting of acute blunt chest trauma.

Effects of Prone Positioning for Patients with Acute Respiratory Distress Syndrome Caused by Pulmonary Contusion: A Single-Center Retrospective Study

Background. The effects of prone positioning (PP) on patients with acute respiratory distress syndrome (ARDS) caused by pulmonary contusion (PC) are unclear. We sought to determine the efficacy of PP among patients whose ARDS was caused by PC. Methods. A retrospective observational study was performed at an intensive care unit (ICU) from January 2017 to June 2021. ARDS patients with PaO2/FiO2 (P/F) < 150 mmHg were enrolled. During the study period, we enrolled 121 patients in the PP group and 117 in the control group. The changes in vital signs, laboratory tests, and compliance of the respiratory system (Crs) were recorded for 3 consecutive days. The mechanical ventilation time, duration of ICU stay, complications, extubation rate, 28-day ventilator-free days, and mortality were also recorded. Results. In the PP group, the P/F and Crs increased over time. Compared to the control group, the P/F and Crs improved in the PP group over 3 consecutive days ( $P<0.05$ ). Furthermore, the PP group also had shorter total mechanical ventilation time (5.1 ± 1.4 vs. 9.3 ± 3.1 days, $P<0.05$ ) and invasive ventilation time (4.9 ± 1.2 vs. 8.7 ± 2.7 days, $P<0.05$ ), shorter ICU stay (7.4 ± 1.8 vs. 11.5 ± 3.6days, $P<0.05$ ), higher extubation rate (95.6% vs. 84.4%, $P<0.05$ ), less atelectasis (15 vs. 74, $P<0.05$ ) and pneumothorax (17 vs. 24, $P>0.05$ ), more 28-day ventilator-free days (21.6 ± 5.2 vs. 16.2 ± 7.2 days, $P<0.05$ ), and lower mortality (4.4% vs. 13.3%, $P<0.05$ ). Conclusions. Among PC cases with moderate to severe ARDS, PP can correct hypoxemia more quickly, improve Crs, reduce atelectasis, increase the extubation rate, shorten mechanical ventilation time and length of ICU stay, and reduce mortality.

Evaluating the Limits in the Biomechanics of Blunt Lung Injury

Thoracic blunt trauma is evident in up to one fifth of all hospital admissions, and is second only to head trauma in motor vehicle crashes. One of the most problematic injury mechanisms associated with blunt thoracic trauma is pulmonary contusion, occurring in up to 75% of blunt thoracic trauma cases. The source and effects of pulmonary contusion caused by blunt lung injury are not well defined, especially within the field of continuum biomechanics. This, paired with unreliable diagnostics for pulmonary contusion, leads to uncertainty in both the clinical entity and mechanics of how to predict presence of injury. There is a distinct need to combine the clinical aspects with mechanical insights through the identification and mitigation of blunt lung trauma and material testing and modeling. This is achieved through using the mechanical insights of lung tissue behavior in order to better understand the injurious mechanisms and courses of treatment of blunt-caused pulmonary contusion. This paper hopes to act as a step forward in connecting two perspectives of blunt lung injury, the clinical entity and mechanical testing and modeling, by reviewing the known literature and identifying the unknowns within the two related fields. Through a review of related literature, clinical evidence is correlated to mechanical data to gain a better understanding of what is being missed in identification and response to blunt lung injury as a whole.

Small Extracellular Vesicles Propagate the Inflammatory Response After Trauma

Trauma is the leading cause of death in individuals under 44 years of age. Thorax trauma (TxT) is strongly associated with trauma-related death, an unbalanced innate immune response, sepsis, acute respiratory distress syndrome, and multiple organ dysfunction. It is shown that different in vivo traumata, such as TxT or an in vitro polytrauma cytokine cocktail trigger secretion of small extracellular nanovesicles (sEVs) from endothelial cells with pro-inflammatory cargo. These sEVs transfer transcripts for ICAM-1, VCAM-1, E-selectin, and cytokines to systemically activate the endothelium, facilitate neutrophil-endothelium interactions, and destabilize barrier integrity. Inhibition of sEV-release after TxT in mice ameliorates local as well as systemic inflammation, neutrophil infiltration, and distant organ damage in kidneys (acute kidney injury, AKI). Vice versa, injection of TxT-plasma-sEVs into healthy animals is sufficient to trigger pulmonary and systemic inflammation as well as AKI. Accordingly, increased sEV concentrations and transfer of similar cargos are observed in polytrauma patients, suggesting a fundamental pathophysiological mechanism.

How to deliver an effective primary survey report for the trauma CT: A radiological and surgical perspective

Whole body contrast-enhanced multidetector CT (WB-CE MDCT) is integral to the assessment of the severely injured patient with stable haemodynamic parameters or in those who respond to resuscitation with blood products. WB-CE MDCT is able to identify the number and severity of injuries sustained by the patient and enable time critical intervention.

In this narrative review article we discuss how communication within the trauma team, including the radiologists and appropriate clinicians is crucial in optimizing the effectiveness of WB-CE MDCT. We review the time critical imaging findings and their clinical relevance, which should be included in a succinct CT primary survey report.

We also discuss the process through which the effectiveness of the trauma report may be maximised and how non technical factors including teamwork may be optimised to facilitate decision making in this high pressure environment.

Imaging Manifestations of Chest Trauma

Trauma is the leading cause of death among individuals under 40 years of age, and pulmonary trauma is common in high-impact injuries. Unlike most other organs, the lung is elastic and distensible, with a physiologic capacity to withstand significant changes in contour and volume. The most common types of lung parenchymal injury are contusions, lacerations, and hematomas, each having characteristic imaging appearances. A less common type of lung injury is herniation. Chest radiography is often the first-line imaging modality performed in the assessment of the acutely injured patient, although there are inherent limitations in the use of this modality in trauma. CT images are more accurate for the assessment of the nature and extent of pulmonary injury than the single-view anteroposterior chest radiograph that is typically obtained in the trauma bay. However, the primary limitations of CT concern the need to transport the patient to the CT scanner and a longer processing time. The American Association for the Surgery of Trauma has established the most widely used grading scale to describe lung injury, which serves to communicate severity, guide management, and provide useful prognostic factors in a systematic fashion. The authors provide an in-depth exploration of the most common types of pulmonary parenchymal, pleural, and airway injuries. Injury grading, patient management, and potential complications of pulmonary injury are also discussed. ^©RSNA, 2021.

IL-17 is a potential biomarker for predicting the severity and outcomes of pulmonary contusion in trauma patients

Pulmonary contusion (PC) is very common in blunt chest trauma, and always results in negative pulmonary outcomes, such as pneumonia, acute respiratory distress syndrome (ARDS), respiratory failure or even death. However, there are no effective biomarkers which can be used to predict the outcomes in these patients. The present study aimed to determine the value of interleukin (IL)-17 and IL-22 in predicting the severity and outcomes of PC in trauma patients. All trauma patients admitted to The First Affiliated Hospital of Guangxi Medical University between January 2015 and December 2017, were studied. Patients aged >14 years old with a diagnosis of PC upon their admission to the emergency department were included. Patients with PC were enrolled as the PC group, patients without PC were enrolled as the non-PC group, and healthy individuals were selected as the control group. Clinical information, including sociodemographic parameters, clinical data, biological findings and therapeutic interventions were recorded for all patients who were enrolled. Blood samples were collected and stored according to the established protocols. PC volume was measured by computed tomography and plasma cytokine levels were assayed by ELISA. A total of 151 patients with PC (PC group) and 159 patients without PC (non-PC group) were included in the present study. In addition, 50 healthy individuals were used as the control group. The primary cause of PC was motor vehicle crashes. PC patients had more rib fractures, but similar injury severity scores compared with other patients. More patients received Pleurocan drainage treatment and had pneumonia complications in the PC group compared with the other two groups. PC patients had a high incidence of ARDS and admission to the intensive care unit (ICU). PC patients also experienced longer periods on mechanical ventilation and had longer stays in the ICU and hospital. PC volume was effective in predicting the outcomes of PC patients. IL-22 levels were similar in the PC group and non-PC group. However, IL-17 could be used as a biomarker to predict the severity of PC, and was strongly associated with PC volume. IL-17 was significantly associated with pro-inflammatory complications in PC patients and could be used as a biomarker for predicting in-patient outcomes of patients with PC. In conclusion, IL-17 is a potential biomarker for predicting the severity and outcomes of PC in trauma patients.

Pulmonary contusions in patients with rib fractures: The need to better classify a common injury

BACKGROUND

Pulmonary contusions are common injuries. Computed tomography reveals vast contused lung volume spectrum, yet pulmonary contusions are defined dichotomously (unilateral vs bilateral). We assessed whether there is stepwise increased risk of pulmonary complications among patients without, with unilateral, and with bilateral pulmonary contusion.

METHODS

We identified adults admitted with rib fractures using the largest US inpatient database. After propensity-score-matching patients without vs with unilateral vs bilateral pulmonary contusions and adjusting for residual confounders, we compared risk for pneumonia, ventilator-associated pneumonia (VAP), respiratory failure, intubation, and mortality.

RESULTS

Among 148,140 encounters of adults with multiple rib fractures, 19% had concomitant pulmonary contusions. Matched patients with pulmonary contusions had increased risk of pneumonia 19% [95%CI:16-33%], respiratory failure 40% [95%CI: 31-50%], and intubation 46% [95%CI: 33-61%]. Delineation showed bilateral contusions, not unilateral contusions, attributed to increased risk of complications.

CONCLUSIONS

There is likely a correlation between contused lung volume and risk of pulmonary complications; dichotomously classifying pulmonary contusions is insufficient. Better understanding this correlation requires establishing the clinically significant contusion volume and a correspondingly refined classification system.

The Effects of Dexmedetomidine and Ketamine on Oxidative Injuries and Histological Changes Following Blunt Chest Trauma

BACKGROUND

The objective of this research was to evaluate the oxidative and histopathological effects of dexmedetomidine and ketamine on the pulmonary contusion model resulting from blunt chest trauma.

METHODS

Rats were randomly assigned to 5 equal groups (n=6): control group (Group C), pulmonary contusion group (Group PC), PC-dexmedetomidine group (Group PC-D), PC-ketamine group (Group PC-K), and PC-dexmedetomidine + ketamine (Group PC-D+K). The PC was performed by dropping a weight of 500 g (2.45 Joules) from a height of 50 cm. In Group PC-D, after chest trauma, dexmedetomidine (100 µg/kg) was administered intraperitoneally. In Group PC-K, after chest trauma, ketamine (100 mg/kg) was administered intraperitoneally. In Group PC-D+K, dexmedetomidine and ketamine were administered together. At the end of the 6th hour, rats were sacrificed. Malondialdehyde (MDA) level, superoxide dismutase (SOD) enzyme activities, neutrophil infiltration/aggregation, and thickness of the alveolar wall were evaluated.

RESULTS

MDA levels were significantly higher in Group PC than Groups C, PC-D, and PC-D+K. SOD enzyme activity was significantly higher in Group PC than Groups C, PC-D, and PC-D+K. In addition, neutrophil infiltration/aggregation and total pulmonary injury scores were significantly higher in Group PC than in other groups, and the thickness of the alveolar wall was significantly higher in Group PC compared to Groups C, PC-D, and PC-D+K. MDA level, SOD enzyme activities, neutrophil infiltration/aggregation, and thickness of alveolar wall were similar in PC-D and PC-D+K groups.

CONCLUSION

Dexmedetomidine and dexmedetomidine+ketamine have protective effects on blunt chest trauma but no protective effect was observed when ketamine was administered alone. We concluded that the administration of dexmedetomidine and ketamine after contusion is beneficial against pulmonary injury in rats.

Blunt trauma related chest wall and pulmonary injuries: An overview

Physical traumas are tragic and multifaceted injuries that suddenly threaten life. Although it is the third most common cause of death in all age groups, one out of four trauma patients die due to thoracic injury or its complications. Blunt injuries constitute the majority of chest trauma. This indicates the importance of chest trauma among all traumas. Blunt chest trauma is usually caused by motor vehicle accident, falling from height, blunt instrument injury and physical assault. As a result of chest trauma, many injuries may occur, such as pulmonary injuries, and these require urgent intervention. Chest wall and pulmonary injuries range from rib fractures to flail chest, pneumothorax to hemothorax and pulmonary contusion to tracheobronchial injuries. Following these injuries, patients may present with a simple dyspnea or even respiratory arrest. For such patient, it is important to understand the treatment logic and to take a multidisciplinary approach to treat the pulmonary and chest wall injuries. This is because only 10% of thoracic trauma patients require surgical operation and the remaining 90% can be treated with simple methods such as appropriate airway, oxygen support, maneuvers, volume support and tube thoracostomy. Adequate pain control in chest trauma is sometimes the most basic and best treatment. With definite diagnosis, the morbidity and mortality can be significantly reduced by simple treatment methods.

Microarray and bioinformatics analysis of circular RNAs expression profile in traumatic lung injury

Acute lung injury (ALI) and respiratory distress syndrome are common, potentially lethal injuries that predominantly occur following chest trauma. Circular RNAs (circRNAs) are stable conserved non-coding RNAs that are widely expressed in different organs. To the best of our knowledge, no previous studies have shown whether circRNAs are involved in traumatic lung injury (TLI). The aim of the present study was to identify highly expressed circRNAs in plasma samples from patients with TLI and explore their potential functions in the pathogenesis of TLI. A high-throughput circRNA microarray was used to investigate the expression profile of circRNAs in plasma samples from five patients with TLI and paired control samples. Subsequently, a total of five abnormally expressed circRNAs were investigated using reverse transcription-quantitative PCR (RT-qPCR). A bioinformatics analysis was performed to predict a competitive endogenous RNA (ceRNA) network. In addition, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were used to identify the main biological processes and pathways. Finally, additional samples were tested to identify the expression profiles of the selected circRNAs. Among the 310 circRNAs that were highly expressed in the microarray analysis, 60 were upregulated and 250 were downregulated in patients with TLI. RT-qPCR results indicated that two downregulated circRNAs (circ_102927 and circ_100562) and one upregulated circRNA (circ_101523) matched the microarray results. The bioinformatics analysis constructed a targeting network based on the three validated circRNAs. GO and KEGG analyses identified the top ten enriched annotations. The expression of homo sapiens circular RNA 102927 (hsa_circRNA_102927) in the plasma of patients with TLI was 0.34-fold compared with the control group in expanded size validation. The results of the present study identified the differentially expressed circRNAs in the plasma of patients with TLI and provided evidence that highly expressed circRNAs involved in the ceRNA network may serve a role in the pathophysiology of TLI.

Lung Contusion in Polytrauma: An Analysis of the TraumaRegister DGU

Background Thorax trauma frequently occurs in which injuries to the bony chest, lung contusions (LCs), and others are diagnosed. The significance of this violation is described very differently and is mostly based on monocentric data.

Methods A retrospective analysis of the TraumaRegister DGU® (TR-DGU) dataset (Project 2014–062) was performed between 2009 and 2014 (injury severity score [ISS] ≥ 16, primary admission to a trauma center, no isolated traumatic brain injury). Patients with LC (Abbreviated Injury Scale [AIS] 3 + 4) were compared with the control group, and an analysis of different age groups was performed.

Results A total of 49,567 patients were included, thereunder 14,521 (29.3%) without relevant thoracic trauma (TT); 95.9% blunt traumas. 18,892 patients (38.1%) had LC and 14,008 (28.3%) had severe LC with AIS 3 + 4; thereunder 72.7% males. For severe LC, the average age was the lowest (44.7 ± 19.7 years) and ISS the highest (30.4 ± 12.1 points).

Intubation, intensive care, (multi-) organ failure, sepsis, and extrathoracic injuries were most common in severe LC. Shock, chest tubes, further thoracic injuries, and patient death occurred most frequently in TT without LC.

Younger patients showed a higher incidence of LC than the older ones; however, high patient age was a highly significant risk factor for the development of complications and poor outcome.

Conclusion Since LC was present in almost 40% of the severely injured and was related to higher morbidity, LC should be detected and managed at the earliest possible time. Proper follow-ups employing chest X-rays and computed tomography (CT) scans are recommended.

Chest Trauma Scoring Systems for Predicting Respiratory Complications in Isolated Rib Fracture

BACKGROUND

We retrospectively compared chest trauma scoring systems in patients with rib fractures without major extrathoracic injury for predicting respiratory complications. We also evaluated the predictive power according to the presence or absence of pulmonary contusion.

MATERIALS AND METHODS

Data from 177 patients with isolated rib fractures were included (December 2013 to April 2018). The primary outcome was respiratory complications (pneumonia, respiratory failure, or empyema). The Abbreviated Injury Scale (AIS), Thoracic Trauma Severity Score (TTSS), Chest Trauma Score (CTS), Rib Fracture Score (RFS), and RibScore were evaluated using univariate and receiver operating characteristic (ROC) analyses to determine their predictive value for pulmonary complications. We divided patients into two groups according to the presence or absence of pulmonary contusion, and constructed ROC curves for both groups.

RESULTS

Twenty-eight patients (15.8%) had ≥1 respiratory complication, with significantly higher numbers of standard, segmental, and displaced rib fractures as well as significantly higher TTSS, CTS, RFS, and AIS scores. In all patients, the TTSS (0.723, 95% confidence interval [CI] 0.651-0.788) showed the highest area under the ROC curve (AUROC), followed by the CTS, RFS, AIS, and RibScore. In patients with pulmonary contusion, TTSS also showed the highest AUROC (0.704, 95% CI 0.613-0.784). In patients without pulmonary contusion, RFS showed the highest AUROC (0.759, 95% CI 0.630-0.861).

CONCLUSIONS

TTSS was the most useful system for predicting respiratory complications in isolated rib fracture patients with pulmonary contusion. By contrast, RFS was the most useful in patients without pulmonary contusion.

Antioxidant treatment after injury suppresses second hit immune priming

BACKGROUND

Pulmonary contusion (PC) is a common injury that often results in priming for exaggerated inflammatory responses to a second hit. Previous studies used a mouse model of pulmonary contusion and showed an early and sustained reduction of SIRT1 protein and activity in the lung and bronchoalveolar lavage (BAL) cells of injured mice. Sustained decrease in SIRT1 was associated with a primed phenotype in injured mice challenged with an inflammatory stimulus. This study tests the hypothesis that pulmonary contusion induces oxidant production that modifies and decreases SIRT1 and primes the lung for the second-hit response.

METHODS

A mouse model of pulmonary contusion was used to investigate injury-induced oxidant changes in SIRT1. Second-hit responses were evaluated by infection (Streptococcus pneumoniae) and inflammatory challenge using bacterial lipopolysaccharide. BAL, lung tissue, and blood were collected and used to evaluate inflammatory responses and SIRT1 levels, oxidant modification, and activity. Levels of NO in the BAL from mice and patients with PC were also assessed.

RESULTS

We found that oxidants produced as a result of pulmonary contusion resulted in modification of SIRT1. S-Nitrosylation was observed and correlated with increased inducible nitric oxide synthase expression after injury. Anti-oxidant treatment of injured mice preserved SIRT1 activity, decreased second hit responses and improved lung function. Elevated NO levels in the BAL of PC patients was associated with acute respiratory distress syndrome or diagnosis of pneumonia.

CONCLUSIONS

We conclude that oxidative stress in the lung after injury induces redox modification of SIRT1 and contributes to priming of the lung for a second-hit response. Antioxidant treatment suggests that SIRT1 activity after injury may be beneficial in suppressing second-hit responses.

Contributing factors in the development of acute lung injury in a murine double hit model

OBJECTIVES

Blunt chest (thoracic) trauma (TxT) is known to contribute to the development of secondary pulmonary complications. Of these, acute lung injury (ALI) is common especially in multiply injured patients and might not only be due to the direct trauma itself, but seems to be caused by ongoing and multifactorial inflammatory changes. Nevertheless, the exact mechanisms and contributing factors of the development of ALI following blunt chest trauma are still elusive.

METHODS

60 CL57BL/6N mice sustained either blunt chest trauma combined with laparotomy without further interventions or a double hit (DH) including TxT and cecal ligation puncture (CLP) after 24 h to induce ALI. Animals were killed either 6 or 24 h after the second procedure. Pulmonary expression of inflammatory mediators cxcl1, cxcl5, IL-1β and IL-6, neutrophil infiltration and lung tissue damage using the Lung Injury Score (LIS) were determined.

RESULTS

Next to a moderate increase in other inflammatory mediators, a significant increase in CXCL1, neutrophil infiltration and lung injury was observed early after TxT, which returned to baseline levels after 24 h. DH induced significantly increased gene expression of cxcl1, cxcl5, IL-1β and IL-6 after 6 h, which was followed by the postponed significant increase in the protein expression after 24 h compared to controls. Neutrophil infiltration was significantly enhanced 24 h after DH compared to all other groups, and exerted a slight decline after 24 h. LIS has shown a significant increase after both 6 and 24 h compared to both control groups as well the late TxT group.

CONCLUSION

Early observed lung injury with moderate inflammatory changes after blunt chest trauma recovered quickly, and therefore, may be caused by mechanical lung injury. In contrast, lung injury in the ALI group did not undergo recovery and is closely associated with significant changes of inflammatory mediators. This model may be used for further examinations of contributing factors and therapeutic strategies to prevent ALI.

Blast injures to the thorax

One out of 10 of military casualties and 6-9 out of 10 civilian victims of terror incidents suffer pulmonary blast injuries when the attackers use explosives as weapon. No specific therapy exists for the primary, shock-wave injury to the lung. The treatment protocols are based on mechanical ventilation, intensive therapy and supportive care. Secondary and tertiary blast structural injuries to the thorax require damage control surgery, dominated by pleural space management (drainage) and haemorrhage control (thoracotomy if needed). Parenchyma resection of irreversibly destroyed lung is rarely needed, and non-anatomical resections are to be preferred. Delayed chest wall reconstruction follows haemodynamic stabilisation and completion of demarcation process. Blast injury to the chest requires a multidisciplinary approach, where the outcome is strongly influenced by the concomitant injuries.

Thoracic damage control surgery

Thoracic damage control surgery (TDCS) is a decision making tool and derivate of the damage control concept (DCC), where physiological stabilization has a priority over anatomical reconstruction under the pressure of time. Intrathoracic haemorrhage control and pleural decompression are the two main immediate tasks of TDCS, while definitive procedures follow when the patient is stabilised in 24-48 hours. The focus of the thoracic surgeon is on the prevention of the haemorrhage induced coagulopathy, metabolic acidosis and hypothermy formed triad of death. Surgical haemorrhage control and pleural space decompression are to be performed. The individual patients benefit from TDCS procedures whose condition is too severe for a complex immediate reconstruction (polytrauma). Life threatening chest injuries in multiple/mass casualty scenarios in civilian and military environment alike are triaged and treated accordingly. Onset of acute mismatch between the resources (available hands, OP theaters, resources, hardware) and the needs (number and severity of chest trauma cases), a mindset shift should take place, where time and space the two main limiting factors. Airway obstruction, tension haemo/pneumothorax falls into the preventable death category. Chest drainage and emergency thoracotomy are the two main procedures offered by TDCS. An intervention structured organ/injury specific list of procedures is detailed. This is a mix of emergency surgery and cardiothoracic surgery, where less is more. TDSC is not the Holy Grail found to solve all complex thoracic trauma cases, but is a good tool to increase the chance for survival in challenging, and frequently quite hopeless situations.

Pulmonary contusion

Lung contusion resulting from chest trauma may be present various clinical pictures. It quite often remains unrecognized and is only suspected later when severe complications have developed. Lung contusion may present in association with chest trauma but may also occur alone. It has to be emphasized, that lung contusion as a clinical identity does not necessarily require a blunt or penetrating chest to be in the background. Nowadays, as a result of traffic accidents, following high energy deceleration, lung contusion may present without an actual tissue damage in the chest wall as a condition initiating an independent, life-threatening generalised process. Although lung contusion shows similarities to blast injury of the lung with respect to clinical consequences, other factors play a role in its aetiology and pathology. Its description and recognition as an independent pathology is not simple. Several approaches exist: thoracic trauma, pulmonary contusion, pulmonary laceration, lung contusion; although these may show similar clinical signs, manifest in different pathologies. Pathologies with similar meaning and possibly similar clinical course cannot, actually, be differentiated; they may accompany other injuries to the trunk, skull or extremities, which, alone, are associated with high morbidity and mortality. Generally, it can be declared that besides high energy, blunt injuries affecting the trunk, lung contusion, has been an often neglected additional radiological finding attached to the main report, despite the fact, that its late consequences crucially determine the prospects of the injured.

Impact of blunt pulmonary contusion in polytrauma patients with rib fractures

BACKGROUND

We investigated the impact of blunt pulmonary contusion (BPC) in patients with rib fractures.

METHODS

Adult patients with rib fractures caused by blunt mechanisms were enrolled over 3 years at a Level 1 trauma center. BPC was defined according to percentage of lung affected as: moderate (1-19% contusion) or severe (≥20% contusion).

RESULTS

In total, 1448 of the 7238 admitted patients had rib fractures. Of these, 321 (22.2%) had BPC: 236 moderate and 85 severe. Patients with BPC were more likely to be admitted to the ICU (moderate: OR 1.55, 95% CI 1.10-2.19; severe: OR 2.74, 95% CI 1.41-5.32). Significantly increased rates of pneumonia (OR 2.52, 95% CI 1.43-4.90) and empyema (OR 4.80, 95% CI 1.07-21.54) were found for moderate and severe BPC, respectively.

CONCLUSIONS

ICU admission and infectious pulmonary complications were more likely with BPC. The presence of BPC on admission CT is also prognostic of increased resource utilization.

Molecular Characterization of Hypoxic Alveolar Epithelial Cells After Lung Contusion Indicates an Important Role for HIF-1α

OBJECTIVE

To understand the fate and regulation of hypoxic type II alveolar epithelial cells (AECs) after lung contusion (LC).

BACKGROUND

LC due to thoracic trauma is a major risk factor for the development of acute respiratory distress syndrome. AECs have recently been implicated as a primary driver of inflammation in LC. The main pathological consequence of LC is hypoxia, and a key mediator of adaptation to hypoxia is hypoxia-inducible factor (HIF)-1. We have recently published that HIF-1α is a major driver of acute inflammation after LC through type II AEC.

METHODS

LC was induced in wild-type mice (C57BL/6), luciferase-based hypoxia reporter mice (ODD-Luc), and HIF-1α conditional knockout mice. The degree of hypoxia was assessed using hypoxyprobe and in vivo imaging system. The fate of hypoxic AEC was evaluated by luciferase dual staining with caspases-3 and Ki-67, terminal deoxynucleotidyl transferase dUTP nick end labeling, and flow cytometry with ApoStat. NLRP-3 expression was determined by western blot. Laser capture microdissection was used to isolate AECs in vivo, and collected RNA was analyzed by Q-PCR for HIF-related pathways.

RESULTS

Global hypoxia was present after LC, but hypoxic foci were not uniform. Hypoxic AECs preferentially undergo apoptosis. There were significant reductions in NLRP-3 in HIF-1α conditional knockout mice. The expression of proteins involved in HIF-related pathways and inflammasome activation were significantly increased in hypoxic AECs.

CONCLUSIONS

These are the first in vivo data to identify, isolate, and characterize hypoxic AECs. HIF-1α regulation through hypoxic AECs is critical to the initiation of acute inflammation after LC.

Pulmonary contusion after bumper car collision: Case report and review of the literature

Thoracic trauma is a major source of morbi-mortality in injured children. Their pliable chest wall makes pulmonary contusion the most common chest injury. It is most often secondary to blunt trauma caused by traffic accidents. We report a case of severe chest trauma caused by a bumper car collision in an 8-years old girl. She sustained right lung contusion that led to complete atelectasis. After a week of supportive therapy, bronchoscopy removed a mucous plug from the main bronchus, resulting in significant clinical improvement. We aim to raise awareness of the risk of severe chest injuries during bumper car collisions.

The use of extracorporeal membrane oxygenation in trauma patients: A national case-control study

Extracorporeal membrane oxygenation (ECMO) has been increasingly applied for the treatment of patients with trauma. Because a common complication of ECMO is bleeding, the use of ECMO support for patients with trauma was limited in the past. Studies have demonstrated a survival benefit from ECMO support in cases of traumatic lung injury, and it is likely that patients with other types of trauma would also benefit from ECMO support. However, the effect of ECMO in patients with other types of trauma is unknown.Using the national insurance data of Taiwan, we identified 810 patients with trauma who received ECMO support from 2000 to 2010. Patients who died or who withdrew from the program within 7 days after discharge were defined as deceased. Logistic regression was used to estimate the odds ratio (OR) of death and 95% confidence intervals (CIs).The overall mortality was 32.8% (266/810). A total of 417 patients received surgery during hospitalization, with an overall mortality of 39.0% (163/417). Patients who underwent thoracic surgery had an OR of 2.23 (95% CI: 1.49-3.34) compared with those who did not. Patients who underwent brain surgery had an OR of 2.86 (95% CI: 1.37-5.98) compared with patients who did not. Patients who received abdominal surgery had an OR of 4.47 (95% CI: 2.63-7.61) compared with patients who did not. All types of surgery had odds of mortality except orthopedic surgery; the use of ECMO with orthopedic surgery had an OR of 1.06 (95% CI: 0.69-1.62) compared with patients who did not receive orthopedic surgery.Except for orthopedic surgery, patients with trauma who received ECMO support and required further surgery during hospitalization exhibited a relatively high mortality rate.

Effectiveness of non-pharmacological interventions for pain and physical function in adults with rib fractures: a systematic review protocol

REVIEW QUESTION/OBJECTIVES

The review question is: what are the effects of non-pharmacological therapeutic interventions on pain and physical function in adults with rib fractures?The objectives of this systematic review are to determine.

Shock waves increase pulmonary vascular leakage, inflammation, oxidative stress, and apoptosis in a mouse model

Severe lung damage is a major cause of death in blast victims, but the mechanisms of pulmonary blast injury are not well understood. Therefore, it is important to study the injury mechanism of pulmonary blast injury. A model of lung injury induced by blast exposure was established by using a simulation blast device. The effectiveness and reproducibility of the device were investigated. Eighty mice were randomly divided into eight groups: control group and 3 h, 6 h, 12 h, 24 h, 48 h, 7 days and 14 days post blast. The explosive device induced an explosion injury model of a single lung injury in mice. The success rate of the model was as high as 90%, and the degree of lung injury was basically the same under the same pressure. Under the same conditions, the thickness of the aluminum film can be from 0.8 mm to 1.6 mm, and the peak pressure could be from 95.85 ± 15.61 PSI to 423.32 ± 11.64 PSI. There is no statistical difference in intragroup comparison. A follow-up lung injury experiment using an aluminum film thickness of 1.4 mm showed a pressure of 337.46 ± 18.30 PSI induced a mortality rate of approximately 23.2%. Compared with the control group (372 ± 23 times/min, 85.9 ± 9.4 mmHg, 4.34 ± 0.09), blast exposed mice had decreased heart rate (283 ± 21 times/min) and blood pressure (73.6 ± 3.6 mmHg), and increased lung wet/dry weight ratio(2.67 ± 0.11), marked edematous lung tissue, ruptured blood vessels, infiltrating inflammatory cells, increased NF-κB (4.13 ± 0.01), TNF-α (4.13 ± 0.01), IL-1β (2.43 ± 0.01) and IL-6 (4.65 ± 0.01) mRNA and protein, decreased IL-10(0.18 ± 0.02) mRNA and protein ( P < 0.05). The formation of ROS and the expression of MDA5 (4.46 ± 0.01) and IREα (3.43 ± 0.00) mRNA and protein were increased and the expression of SOD-1 (0.28 ± 0.02) mRNA and protein was decreased ( P < 0.05). Increased expression of Bax (3.54 ± 0.00) and caspase 3 (4.18 ± 0.01) mRNA and protein inhibited the expression of Bcl-2 (0.39 ± 0.02) mRNA and protein. The changes of pulmonary edema, inflammatory cell infiltration, and cell damage factor expression increased gradually with time, and reached the peak at 12-24 h after the outbreak, and returned to normal at 7-14 days. Detonation injury can lead to edema of lung tissue, pulmonary hemorrhage, rupture of pulmonary vessels, induction of early inflammatory responses accompanied by increased oxidative stress in lung tissue cells and increased apoptosis in mice experiencing blast injury. The above results are consistent with those reported in other literatures. It is showed that the mouse lung blast injury model is successfully modeled, and the device can be used for the study of pulmonary blast injury. Impact statement The number of patients with explosive injury has increased year by year, but there is no better treatment. However, the research on detonation injury is difficult to carry out. One of the factors is the difficulty in making the model of blast injury. The laboratory successfully developed and produced a simulation device of explosive knocking through a large amount of literature data and preliminary experiments, and verified the preparation of the simulation device through various experimental techniques. The results showed that the device could simulate the shock wave-induced acute lung injury generated, which was similar to the actual knocking injury. The experimental process was controlled. Under the same condition, there was no statistical difference between the groups. It is possible to realize miniaturization and precision of an explosive knocking simulation device, which is a good experimental tool for further research on the mechanism of organ damage caused by detonation and the development of protective drugs.

Rotational therapy in thoracic injuries: what is the evidence?

PURPOSE OF REVIEW

To review the current use of continuous lateral rotational therapy (CLRT) in patients with thoracic injuries and its impact on clinical course, complications and outcome.

RECENT FINDINGS

Patient positioning is a key factor in the treatment of severe thoracic injuries and CLRT, and intermittent supine and prone position are basic options. There is a lack of randomized controlled studies for trauma patients with chest injury undergoing kinetic therapy as standard of care. A positive effect of kinetic therapy for prevention of secondary respiratory complications has been reported; nevertheless, no positive effect on mortality or length of hospital stay could be affirmed so far. In general, standardized therapeutic regimes for treatment of chest trauma have been implemented, including ventilator settings and positioning therapy. However, the available data do not allow a clear recommendation for rotational/kinetic therapy or prone positioning as superior or inferior.

SUMMARY

The benefit of changing the patients' position for secret mobilization and recruitment of atelectasis after chest trauma and therefore preventing secondary complications seems to be self-evident. Since only few studies report about the utility of CLRT in critically ill chest trauma patients, randomized controlled multicenter trials are necessary to analyze the overall benefit of such means.

Outcomes of preinjury anticoagulation in patients with traumatic rib fractures

BACKGROUND

Anticoagulant and antiplatelet agents (ACAP) have been shown to negatively affect trauma patients.

METHODS

Outcomes in adults with rib fractures were reviewed. Pearson chi-square test was used for analysis. Multivariate logistic regression was used to adjust for potential confounders.

RESULTS

Of the 1448 included patients, 149 (10.3%) took preinjury ACAP; these patients were significantly older than non-anticoagulated patients (72 vs. 54 years, P ≤ 0.05). There was no difference in pulmonary complications, ICU admissions or ICU LOS. The preinjury ACAP group had a significantly longer LOS (12.03 vs. 9.33 days, P = 0.004), fewer pulmonary contusions (15.43% vs. 22.94%, P = 0.037), and fewer thoracic drainage procedures (10.74% vs. 18.17%, P = 0.023). Multivariate adjustment for possible confounders revealed that patients taking warfarin had a significantly longer LOS (+7.38 days). After adjustment there was no difference in mortality.

CONCLUSION

Preinjury ACAP use does not increase mortality or morbidity in patients with rib fractures.

SUMMARY

We demonstrated that preinjury anticoagulation and antiplatelet agents do not increase mortality or morbidity in patients with rib fractures. However, they lead to a longer hospital length of stay, particularly in patients on warfarin.

Pulmonary contusions in the elderly after blunt trauma: incidence and outcomes

BACKGROUND

In the general population with blunt chest trauma, pulmonary contusions (PCs) are commonly identified. However, there is limited research in the elderly. We sought to evaluate the incidence and outcomes of PCs in elderly blunt trauma admissions.

METHODS

We retrospectively reviewed the trauma registry at a level I trauma center for all blunt thoracic trauma patients aged ≥65 y, who were admitted between 2007 and 2015. The medical records of PC patients were reviewed.

RESULTS

There were 956 admissions with blunt thoracic trauma; of which 778 had no pulmonary contusion (NO) and 178 had PC. The major mechanisms of injury were falls (58.7% NO, 39.3% PC, P <0.001) and motor vehicle crash/motor cycle crash (35.6% NO, 51.7% PC, P <0.001). Rib fractures were present in 79.8% of PC and 73.8% of NO patients, P = 0.1. PC patients more often had serious (AIS ≥3) head/neck (30.3% versus 20.6%, P <0.001), abdomen (12.4% versus 6.6%, P <0.001), and extremity injuries (20.8% versus 11.4%, P <0.001). Complication (46.1% PC versus 26.6% NO, P <0.001) and mortality (14.0% PC versus 6.2% NO, P = 0.0003) rates were higher in PC patients. On multivariate logistic regression analyses, PC presence was significantly associated with mechanical ventilation (odds ratio 2.5), intensive care unit admission (odds ratio 2.3), and mortality (odds ratio 1.9).

CONCLUSIONS

Over 18.6% of elderly blunt thoracic trauma patients sustained PC, despite an often low energy mechanism of injury. The presence of a PC should prompt investigation for other serious intrathoracic and extrathoracic injuries. PC presence is associated with substantial morbidity and mortality.

Patterns of invasive mechanical ventilation in patients with severe blunt chest trauma and lung contusion: A French multicentric evaluation of practices

Introduction

This study investigated invasive mechanical ventilation modalities used in severe blunt chest trauma patients with pulmonary contusion. Occurrence, risk factors, and outcomes of early onset acute respiratory distress syndrome were also evaluated.

Methods

We performed a retrospective multicenter observational study including 115 adult patients hospitalized in six level 1 trauma intensive care units between April and September of 2014. Independent predictors of early onset acute respiratory distress syndrome were determined by multiple logistic regression analysis based on clinical characteristics and initial management.

Results

Protective ventilation principles were highly implemented, even prophylactically before acute respiratory distress syndrome occurrence. Early onset acute respiratory distress syndrome appeared to be associated with lung contusion of >20% of total lung volume and early onset pneumonia.

Conclusions

Predictors of early onset acute respiratory distress syndrome could help with identifying high-risk populations, potentially improving case management through specific protocol development for these patients.

An Analysis of Presentation, Pattern and Outcome of Chest Trauma Patients at an Urban Level 1 Trauma Center

Chest trauma is an important public health problem accounting for a substantial proportion of all trauma admissions and deaths. It directly account for 20-25 % of deaths due to trauma. Therefore, this study was conducted to analyze the presentation, patterns, and outcome of chest trauma in a level-1 urban trauma center. It was a prospective observational study of all patients presented with chest trauma to an urban level 1-trauma center over a period of 3 years. Demographic profile, mechanism of injury, injury severity scores (ISS), associated injuries, hospital stay, etc. were recorded. Morbidity and mortality rates were analyzed and compared with the published literature. Chest injuries comprised 30.9 % of all trauma admissions and the mechanism was blunt in majority (83.5 %) of the cases. Vehicular crashes (59.7 %) followed by assault were the most common modes of injury. Rib fracture was the most common chest injury seen in 724 of the 1258 patients while abdominal visceral injuries were the commonest associated injuries in polytrauma cases. Majority of the patients were managed non-operatively. Inter costal tube drainage (ICD) was the main stay of treatment in 75 % of the cases, whereas, thoracotomy was required only in 5.56 % of the patients. Overall mortality was 11 % and it was found to be significantly higher following blunt chest trauma. We observed that associated extra thoracic injuries resulted in higher mortality as compared to isolated chest injuries. Thoracic injuries can be readily diagnosed in the emergency department by meticulous and repeated clinical evaluation and majority require simple surgical procedures to prevent immediate mortality and long-term morbidity.