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

Classification methods of pulmonary contusion based on chest CT and the association with in-hospital outcomes: a systematic review of literature

INTRODUCTION

Patients sustaining pulmonary contusion (PC) have a higher risk of complications and long-term respiratory difficulty. Computed tomography (CT) scans have a high sensitivity for PC. However, since PC develops over time, CT scans made directly post-trauma may underestimate the full extent of PC. This creates a need to better define in which PC-patients complications are more likely. The aim of this systematic review was to identify different classification systems of PC, and investigate the association between amount of PC and in-hospital outcomes.

METHODS

A systematic review was conducted in accordance with PRISMA guidelines. Studies reporting a classification system for PC after blunt thoracic trauma based on a CT scan were included. Outcomes were classification method of PC and the relation between classification and pulmonary complications and in-hospital outcomes.

RESULTS

Twenty studies were included. Total number of patients ranged from 49 to 148,140 patients. The most common classification system used was calculating the percentage of contused lung volume. Other classification methods were based on Blunt Pulmonary Contusion score-6 and -18, Abbreviated Injury Score and Thoracic Trauma Severity scores. Worse outcomes were generally associated with between > 18 to > 24% contusion volume.

DISCUSSION

The heterogeneity of currently available literature makes comparing classification methods challenging. The most common classification of PC was based on volumetric analysis. Calculating a percentage of PC as part of the total volume allows for the highest level of segmentation of lung parenchyma as compared to using BPC-6, BPC-18, or AIS. Contusion volume exceeding 18-24% was generally associated with worse outcomes.

Surgical stabilization of rib fractures (SSRF): the WSES and CWIS position paper

BACKGROUND

Rib fractures are one of the most common traumatic injuries and may result in significant morbidity and mortality. Despite growing evidence, technological advances and increasing acceptance, surgical stabilization of rib fractures (SSRF) remains not uniformly considered in trauma centers. Indications, contraindications, appropriate timing, surgical approaches and utilized implants are part of an ongoing debate. The present position paper, which is endorsed by the World Society of Emergency Surgery (WSES), and supported by the Chest Wall Injury Society, aims to provide a review of the literature investigating the use of SSRF in rib fracture management to develop graded position statements, providing an updated guide and reference for SSRF.

METHODS

This position paper was developed according to the WSES methodology. A steering committee performed the literature review and drafted the position paper. An international panel of experts then critically revised the manuscript and discussed it in detail, to develop a consensus on the position statements.

RESULTS

A total of 287 studies (systematic reviews, randomized clinical trial, prospective and retrospective comparative studies, case series, original articles) have been selected from an initial pool of 9928 studies. Thirty-nine graded position statements were put forward to address eight crucial aspects of SSRF: surgical indications, contraindications, optimal timing of surgery, preoperative imaging evaluation, rib fracture sites for surgical fixation, management of concurrent thoracic injuries, surgical approach, stabilization methods and material selection.

CONCLUSION

This consensus document addresses the key focus questions on surgical treatment of rib fractures. The expert recommendations clarify current evidences on SSRF indications, timing, operative planning, approaches and techniques, with the aim to guide clinicians in optimizing the management of rib fractures, to improve patient outcomes and direct future research.

The pulmonary contusion score: Development of a simple scoring system for blunt lung injury

Background

Pulmonary contusions (PC) are common after blunt chest trauma and can be identified with computed tomography (CT). Complex scoring systems for grading PC exist, however recent scoring systems rely on computer-generated algorithms that are not readily available at all hospitals. We developed a scoring system for grading PC to predict the need for prolonged mechanical ventilation and initial hospital admission location.

Methods

A retrospective review was performed of adult blunt trauma patients with PC identified on initial chest CT during 2020. Data elements related to demographics, injury characteristics, disposition and healthcare utilization were extracted. The primary outcome was the need for mechanical ventilation for greater than 48 h. A novel scoring system, the Pulmonary Contusion Score (PCS) was developed. The maximum score was 10, with each lobe contributing up to 2 points. A score of 0 was given for no contusion present in the lobe, 1 for less than 50 % contusion, and 2 for greater than 50 % contusion. A PCS of 4 was hypothesized to correlate with need for mechanical ventilation for over 48 h. A confusion matrix of the scoring algorithm was created, and inter-rater concordance was calculated from a randomly selected 125 patients.

Results

A total of 217 patients were identified. 118 patients (54 %) were admitted to the ICU, but only 23 patients (19 %) were intubated, and only 17 patients (8 %) required mechanical ventilation > 48 h. Sensitivity of the scoring system was 20 %, while specificity was 93 %. Negative predictive value was 93 %. Inter-rater agreement was 77 %.

Conclusion

The PCS is a scoring system with high specificity and negative predictive value that can be used to evaluate the need for mechanical ventilation after sustaining blunt PC and can help properly allocate hospital resources.

Level of evidence

IV - diagnostic criteria.

Physiologic parameters and radiologic findings can predict pulmonary complications and guide management in traumatic rib fractures

BACKGROUND

Traumatic rib fracture is associated with a high morbidity rate and identifying patients at risk of developing pulmonary complications (PC) can guide management and potentially decrease unnecessary intensive care admissions. Therefore, we sought to assess and compare the utility of a physiologic parameter, vital capacity (VC), with the admission radiologic findings (RibScore) in predicting PC in patients with rib fractures.

METHODS

This is a single-center retrospective review (2015-2018) of all adult (≥18 years) patients admitted to a Level I trauma center with traumatic rib fracture. Exclusion criteria included no CT scan and absence of VC within 48 h of admission. The cohort was stratified into two groups based on presence or absence of PC (pneumonia, unplanned intubation, unplanned transfer to the intensive care unit for a respiratory concern, or the need for a tracheostomy). Multivariable logistic regression models were constructed to identify predictors of PC.

RESULTS

A total of 654 patients met the inclusion criteria of whom 70 % were males. The median age was 51 years and fall (48 %) was the most common type of injury. A total of 36 patients (5.5 %) developed a pulmonary complication. These patients were more likely to be older, had a higher ISS, and were more likely to require a tube thoracostomy placement. On multivariable logistic regression, first VC ≤30 % (AOR: 4.29), day 1 VC ≤30 % (AOR: 3.61), day 2 VC ≤30 % (AOR: 5.54), Δ(Day2-Day1 VC) (AOR: 0.96), and RibScore ≥2 (AOR: 3.19) were significantly associated with PC. On discrimination analysis, day 2 VC had the highest area under the receiver operating characteristic curve (AuROC), 0.81, and was superior to first VC and day 1 VC in predicting PC. There was no statistically significant difference in predicting PC between day 2 VC and RibScore. On multivariable analysis, first VC ≤30 %, day 1 VC ≤30 %, day 2 VC ≤30 %, and admission RibScore ≥2 were associated with prolonged hospital and ICU LOS.

CONCLUSION

VC and RibScore emerged as independent predictors of PC. However, VC was not found to be superior to RibScore in predicting PC. Further prospective research is warranted to validate the findings of this study.

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.

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.

[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.

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.

Imaging findings of pulmonary contusions on multidetector CT: A retrospective study comparing adults and children

To describe imaging findings of pulmonary contusions (PC) in adults and children using multidetector computed tomography (CT) scanners. We conducted a retrospective single center study. All chest multidetector computed tomography (MDCT) scans of victims of blunt trauma admitted to the emergency unit of a reference trauma center of Brazil between January 2015 and December 2016 were reviewed in search of opacities compatible with PC. The CT images were analyzed in conjunction with medical records, that provided demographic and clinical data. The obtained data were analyzed in the overall population and comparing children and adults. Significant P value was defined as <.05. 52.7% of patients presented bilateral opacities. Middle third, posterior and peripheral portions of the lungs were more frequently affected, in the craniocaudal, anteroposterior and axial axes, respectively. A vast majority of patients (80.6%) presented multiple opacities, whereas a minority showed subpleural sparing (26.9%) and fissure crossing (22.6%), with similar frequencies in children and adults. Children, although, more frequently presented consolidation and more diffuse lesions in the anteroposterior axis compared to adults, with statistically significant differences. PC usually are multiple and predominate in middle, posterior and peripheral portions of the lungs. Subpleural sparing and fissure crossing seems to be infrequent and have similar frequencies between children and adults. Although, there are differences between these age groups, as younger people tend to have more consolidation and diffuse opacities in the anteroposterior axis than older ones.

Scalable Deep Learning Algorithm to Compute Percent Pulmonary Contusion among Patients with Rib Fractures

BACKGROUND

Pulmonary contusion exists along a spectrum of severity, yet is commonly binarily classified as present or absent. We aimed to develop a deep learning algorithm to automate percent pulmonary contusion computation and exemplify how transfer learning could facilitate large-scale validation. We hypothesized our deep learning algorithm could automate percent pulmonary contusion computation and that greater percent contusion would be associated with higher odds of adverse inpatient outcomes among patients with rib fractures.

METHODS

We evaluated admission-day chest computed tomography (CT) scans of adults aged ≥18 years admitted to our institution with multiple rib fractures and pulmonary contusions (2010-2020). We adapted a pre-trained convolutional neural network that segments 3-dimensional lung volumes and segmented contused lung parenchyma, pulmonary blood vessels, and computed percent pulmonary contusion. Exploratory analysis evaluated associations between percent pulmonary contusion (quartiles) and odds of mechanical ventilation, mortality, and prolonged hospital length-of-stay using multivariable logistic regression. Sensitivity analysis included pulmonary blood vessel volumes during percent contusion computation.

RESULTS

A total of 332 patients met inclusion criteria (median 5 rib fractures), among whom 28% underwent mechanical ventilation and 6% died. The study population's median (IQR) percent pulmonary contusion was 4(2-8)%. Compared to the lowest quartile of percent pulmonary contusion, each increasing quartile was associated with higher adjusted odds of undergoing mechanical ventilation (OR[95%CI]: 1.5[1.1-2.1]) and prolonged hospitalization (OR[95%CI]: 1.6[1.1-2.2]), but not with mortality (OR[95%CI]: 1.1 [0.6-2.0]. Findings were similar on sensitivity analysis.

CONCLUSION

We developed a scalable deep learning algorithm to automate percent pulmonary contusion calculating using chest CTs of adults admitted with rib fractures. Open code sharing and collaborative research is needed to validate our algorithm and exploratory analysis at large scale. Transfer learning can help harness the full potential of big data and high-performing algorithms to bring precision medicine to the bedside.

LEVEL OF EVIDENCE

IV.

ICU Length of Stay and Factors Associated with Longer Stay of Major Trauma Patients with Multiple Rib Fractures: A Retrospective Observational Study

Background. Chest injury with multiple rib fractures is the most common injury among major trauma patients in New South Wales (23%) and is associated with a high rate of mortality and morbidity. The aim of this study was to determine the intensive care unit (ICU) length of stay (LOS) among major trauma patients with multiple rib fractures and to identify factors associated with a prolonged ICU LOS. Materials and Methods. Single-centre, retrospective observational cohort study of adult patients with 3 or more traumatic rib fractures, who were admitted to ICU between June 2014 and June 2019. A comparison was made between patients who stayed in ICU for less than 7 days and those that stay for 7 or more days. Results. Among 215 patients who were enrolled, 150 (69.7%) were male, the median Injury Severity Score (ISS) was 24 (interquartile range (IQR): 17–32). The median ICU LOS was 4 (IQR: 2–7) days and the average ICU LOS was 6.5 (SD 8.5; 95% CI 5.3–7.6) days. The median number of rib fractures was 6 (IQR: 5–9) and 76 (35.3%) patients had a flail chest. Patients who stayed longer than 7 days in ICU had higher ISS, higher APACHE-II score, greater number of rib fractures, higher rate of lung contusions, and required more respiratory support of any type. Conclusions. ISS, number of rib fractures, lung contusion, and flail chest were associated with prolonged ICU LOS in patients with traumatic multiple rib fractures.

The Chinese consensus for surgical treatment of traumatic rib fractures 2021 (C-STTRF 2021)

Rib fracture is the most common injury in chest trauma. Most of patients with rib fractures were treated conservatively, but up to 50% of patients, especially those with combined injury such as flail chest, presented chronic pain or chest wall deformities, and more than 30% had long-term disabilities, unable to retain a full-time job. In the past two decades, surgery for rib fractures has achieving good outcomes. However, in clinic, there are still some problems including inconsistency in surgical indications and quality control in medical services. Before the year of 2018, there were 3 guidelines on the management of regional traumatic rib fractures were published at home and abroad, focusing on the guidance of the overall treatment decisions and plans; another clinical guideline about the surgical treatment of rib fractures lacks recent related progress in surgical treatment of rib fractures. The Chinese Society of Traumatology, Chinese Medical Association, and the Chinese College of Trauma Surgeons, Chinese Medical Doctor Association organized experts from cardiothoracic surgery, trauma surgery, acute care surgery, orthopedics and other disciplines to participate together, following the principle of evidence-based medicine and in line with the scientific nature and practicality, formulated the Chinese consensus for surgical treatment of traumatic rib fractures (STTRF 2021). This expert consensus put forward some clear, applicable, and graded recommendations from seven aspects: preoperative imaging evaluation, surgical indications, timing of surgery, surgical methods, rib fracture sites for surgical fixation, internal fixation method and material selection, treatment of combined injuries in rib fractures, in order to provide guidance and reference for surgical treatment of traumatic rib fractures.