Occult pneumothorax in trauma patients: should this be sought in the focused assessment with sonography for trauma examination?

Role of Interventional Radiology in the Management of Non-aortic Thoracic Trauma

Trauma remains a leading cause of death for all age groups, and nearly two-thirds of these individuals suffer thoracic trauma. Due to the various types of injuries, including vascular and nonvascular, interventional radiology plays a major role in the acute and chronic management of the thoracic trauma patient. Interventional radiologists are critical members in the multidisciplinary team focusing on treatment of the patient with thoracic injury. Through case presentations, this article will review the role of interventional radiology in the management of trauma patients suffering thoracic injuries.

Point-of-care ultrasonography for diagnosing thoracoabdominal injuries in patients with blunt trauma

BACKGROUND

Point-of-care sonography (POCS) has emerged as the screening modality of choice for suspected body trauma in many emergency departments worldwide. Its best known application is FAST (focused abdominal sonography for trauma). The technology is almost ubiquitously available, can be performed during resuscitation, and does not expose patients or staff to radiation. While many authors have stressed the high specificity of POCS, its sensitivity varied markedly across studies. This review aimed to compile the current best evidence about the diagnostic accuracy of POCS imaging protocols in the setting of blunt thoracoabdominal trauma.

OBJECTIVES

To determine the diagnostic accuracy of POCS for detecting and excluding free fluid, organ injuries, vascular lesions, and other injuries (e.g. pneumothorax) compared to a diagnostic reference standard (i.e. computed tomography (CT), magnetic resonance imaging (MRI), thoracoscopy or thoracotomy, laparoscopy or laparotomy, autopsy, or any combination of these) in patients with blunt trauma.

SEARCH METHODS

We searched Ovid MEDLINE (1946 to July 2017) and Ovid Embase (1974 to July 2017), as well as PubMed (1947 to July 2017), employing a prospectively defined literature and data retrieval strategy. We also screened the Cochrane Library, Google Scholar, and BIOSIS for potentially relevant citations, and scanned the reference lists of full-text papers for articles missed by the electronic search. We performed a top-up search on 6 December 2018, and identified eight new studies which may be incorporated into the first update of this review.

SELECTION CRITERIA

We assessed studies for eligibility using predefined inclusion and exclusion criteria. We included either prospective or retrospective diagnostic cohort studies that enrolled patients of any age and gender who sustained any type of blunt injury in a civilian scenario. Eligible studies had to provide sufficient information to construct a 2 x 2 table of diagnostic accuracy to allow for calculating sensitivity, specificity, and other indices of diagnostic test accuracy.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles, abstracts, and full texts of reports using a prespecified data extraction form. Methodological quality of individual studies was rated by the QUADAS-2 instrument (the revised and updated version of the original Quality Assessment of Diagnostic Accuracy Studies list of items). We calculated sensitivity and specificity with 95% confidence intervals (CI), tabulated the pairs of sensitivity and specificity with CI, and depicted these estimates by coupled forest plots using Review Manager 5 (RevMan 5). For pooling summary estimates of sensitivity and specificity, and investigating heterogeneity across studies, we fitted a bivariate model using Stata 14.0.

MAIN RESULTS

We included 34 studies with 8635 participants in this review. Summary estimates of sensitivity and specificity were 0.74 (95% CI 0.65 to 0.81) and 0.96 (95% CI 0.94 to 0.98). Pooled positive and negative likelihood ratios were estimated at 18.5 (95% CI 10.8 to 40.5) and 0.27 (95% CI 0.19 to 0.37), respectively. There was substantial heterogeneity across studies, and the reported accuracy of POCS strongly depended on the population and affected body area. In children, pooled sensitivity of POCS was 0.63 (95% CI 0.46 to 0.77), as compared to 0.78 (95% CI 0.69 to 0.84) in an adult or mixed population. Associated specificity in children was 0.91 (95% CI 0.81 to 0.96) and in an adult or mixed population 0.97 (95% CI 0.96 to 0.99). For abdominal trauma, POCS had a sensitivity of 0.68 (95% CI 0.59 to 0.75) and a specificity of 0.95 (95% CI 0.92 to 0.97). For chest injuries, sensitivity and specificity were calculated at 0.96 (95% CI 0.88 to 0.99) and 0.99 (95% CI 0.97 to 1.00). If we consider the results of all 34 included studies in a virtual population of 1000 patients, based on the observed median prevalence (pretest probability) of thoracoabdominal trauma of 28%, POCS would miss 73 patients with injuries and falsely suggest the presence of injuries in another 29 patients. Furthermore, in a virtual population of 1000 children, based on the observed median prevalence (pretest probability) of thoracoabdominal trauma of 31%, POCS would miss 118 children with injuries and falsely suggest the presence of injuries in another 62 children.

AUTHORS' CONCLUSIONS

In patients with suspected blunt thoracoabdominal trauma, positive POCS findings are helpful for guiding treatment decisions. However, with regard to abdominal trauma, a negative POCS exam does not rule out injuries and must be verified by a reference test such as CT. This is of particular importance in paediatric trauma, where the sensitivity of POCS is poor. Based on a small number of studies in a mixed population, POCS may have a higher sensitivity in chest injuries. This warrants larger, confirmatory trials to affirm the accuracy of POCS for diagnosing thoracic trauma.

Do clinical guidelines for whole body computerised tomography in trauma improve diagnostic accuracy and reduce unnecessary investigations? A systematic review and narrative synthesis

Introduction

Whole body computerised tomography has become a standard of care for the investigation of major trauma patients. However, its use varies widely, and current clinical guidelines are not universally accepted. We undertook a systematic review of the literature to determine whether clinical guidelines for whole body computerised tomography in trauma increase its diagnostic accuracy.

Materials and methods

A systematic review of Medline, Cinhal and the Cochrane database, supplemented by a manual search of relevant papers was undertaken, with narrative synthesis. Studies comparing clinical guidelines to physician gestalt for the use of whole body computerised tomography in adult trauma were included.

Results

A total of 887 papers were identified from the electronic databases, and 1 from manual searches. Of these, seven papers fulfilled the inclusion criteria. Two papers compared clinical guidelines with routine practice: one found increased diagnostic accuracy while the other did not. Two papers investigated the performance of established clinical guidelines and demonstrated moderate sensitivity and low specificity. Two papers compared different components of established triage tools in trauma. One paper devised a de novo clinical decision rule, and demonstrated good diagnostic accuracy with the tool. The outcome criteria used to define a ‘positive’ scan varied widely, making direct comparisons between studies impossible.

Conclusions

Current clinical guidelines for whole body computerised tomography in trauma may increase the sensitivity of the investigation, but the evidence to support this is limited. There is a need to standardise the definition of a ‘clinically significant’ finding on CT to allow better comparison of diagnostic studies.

Are first rib fractures a marker for other life-threatening injuries in patients with major trauma? A cohort study of patients on the UK Trauma Audit and Research Network database

BACKGROUND

First rib fractures are considered indicators of increased morbidity and mortality in major trauma. However, this has not been definitively proven. With an increased use of CT and the potential increase in detection of first rib fractures, re-evaluation of these injuries as a marker for life-threatening injuries is warranted.

METHODS

Patients sustaining rib fractures between January 2012 and December 2013 were investigated using data from the UK Trauma Audit and Research Network. The prevalence of life-threatening injuries was compared in patients with first rib fractures and those with other rib fractures. Multivariate logistic regression was performed to determine the association between first rib fractures, injury severity, polytrauma and mortality.

RESULTS

There were 1683 patients with first rib fractures and 8369 with fractures of other ribs. Life-threatening intrathoracic and extrathoracic injuries were more likely in patients with first rib fractures. The presence of first rib fractures was a significant predictor of injury severity (Injury Severity Score >15) and polytrauma, independent of mechanism of injury, age and gender with an adjusted OR of 2.64 (95% CI 2.33 to 3.00) and 2.01 (95% CI 1.80 to 2.25), respectively. Risk-adjusted mortality was the same in patients with first rib fractures and those with other rib fractures (adjusted OR 0.97, 95% CI 0.79 to 1.19).

CONCLUSION

First rib fractures are a marker of life-threatening injuries in major trauma, though they do not independently increase mortality. Management of patients with first rib fractures should focus on identification and treatment of associated life-threatening injuries.

"Anterior convergent" chest probing in rapid ultrasound transducer positioning versus formal chest ultrasonography to detect pneumothorax during the primary survey of hospital trauma patients: a diagnostic accuracy study

Background

Occult pneumothorax represents a diagnostic pitfall during the primary survey of trauma patients, particularly if these patients require early positive pressure ventilation. This study investigated the accuracy of our proposed rapid model of ultrasound transducer positioning during the primary survey of trauma patients after their arrival at the hospital.

Methods

This diagnostic trial was conducted over 12 months and was based on the results of 84 ultrasound (US) exams performed on patients with severe multiple trauma. Our index test (US) was used to detect pneumothorax in four pre-defined locations on the anterior of each hemi-thorax using the “Anterior Convergent” approach, and its performance was limited to the primary survey. Consecutively, patients underwent chest-computed tomography (CT) with or without chest radiography. The diagnostic findings of both chest radiography and chest ultrasounds were compared to the gold-standard test (CT).

Results

The diagnostic sensitivity was 78 % for US and 36.4 % for chest radiography (p < 0.001); the specificity was 92 % for US and 98 % for chest radiography (not significant); the positive predictive values were 74 % for US and 80 % for chest radiography (not significant); the negative predictive values were 94 % for US and 87 % for chest radiography (not significant); the positive likelihood ratio was 10 for US and 18 for chest radiography (p = 0.007); and the negative likelihood ratio was 0.25 for US and 0.65 for chest radiography (p = 0.001). The mean required time for performing the new method was 64 ± 10 s. An absence of the expected diffused dynamic view among ultrasound images obtained from patients with pneumothorax was also observed. We designated this phenomenon “Gestalt Lung Recession.”

Conclusions

“Anterior convergent” chest US probing represents a brief but efficient model that provides clinicians a safe and accurate exam and adequate resuscitation during critical minutes of the primary survey without interrupting other medical staff activities taking place around the trauma patient. The use of the new concept of “Gestalt Lung Recession” instead of the absence of “lung sliding” might improve the specificity of US in detecting pneumothorax.

Clinician-performed Beside Ultrasound for the Diagnosis of Traumatic Pneumothorax

Introduction:

Prior studies have reported conflicting results regarding the utility of ultrasound in the diagnosis of traumatic pneumothorax (PTX) because they have used sonologists with extensive experience. This study evaluates the characteristics of ultrasound for PTX for a large cohort of trauma and emergency physicians.

Methods:

This was a prospective, observational study on a convenience sample of patients presenting to a trauma center who had a thoracic ultrasound (TUS) evaluation for PTX performed after the Focused Assessment with Sonography for Trauma exam. Sonologists recorded their findings prior to any other diagnostic studies. The results of TUS were compared to one or more of the following: chest computed tomography, escape of air on chest tube insertion, or supine chest radiography followed by clinical observation.

Results:

There were 549 patients enrolled. The median injury severity score of the patients was 5 (inter-quartile range [IQR] 1–14); 36 different sonologists performed TUS. Forty-seven of the 549 patients had traumatic PTX, for an incidence of 9%. TUS correctly identified 27/47 patients with PTX for a sensitivity of 57% (confidence interval [CI] 42–72%). There were 3 false positive cases of TUS for a specificity of 99% (CI 98%–100%). A “wet” chest radiograph reading done in the trauma bay showed a sensitivity of 40% (CI 23–59) and a specificity of 100% (99–100).

Conclusion:

In a large heterogenous group of clinicians who typically care for trauma patients, the sonographic evaluation for pneumothorax was as accurate as supine chest radiography. Thoracic ultrasound may be helpful in the initial evaluation of patients with truncal trauma.

Initial management and resuscitation of severe chest trauma

Severe chest trauma, blunt or penetrating, is responsible for up to 25% of traumatic deaths in North America. Respiratory compromise is the most frequent dramatic presentation in blunt trauma, while injuries to the heart and great vessels pose the greatest risk of immediate death following penetrating trauma. More than 80% of patients will be managed with interventions that can be performed in the emergency department. This article reviews the presentation, diagnosis, and management of the most important thoracic injuries. A structured approach to the acutely unstable patient is proposed to guide resuscitation decisions.

Principles of diagnosis and management of traumatic pneumothorax

Presence of air and fluid with in the chest might have been documented as early as Fifth Century B.C. by a physician in ancient Greece, who practiced the so-called Hippocratic succession of the chest. This is due to a development of communication between intrapulmonary air space and pleural space, or through the chest wall between the atmosphere and pleural space. Air enters the pleural space until the pressure gradient is eliminated or the communication is closed. Increasing incidence of road traffic accidents, increasing awareness of healthcare leading to more advanced diagnostic procedures, and increasing number of admissions in intensive care units are responsible for traumatic (noniatrogenic and iatrogenic) pneumothorax. Clinical spectrum of pneumothorax varies from asymptomatic patient to life-threatening situations. Diagnosis is usually made by clinical examination. Simple erect chest radiograph is sufficient though; many investigations are useful in accessing the future line of action. However, in certain life-threatening conditions obtaining imaging studies can causes an unnecessary and potential lethal delay in treatment.

Ultrasound Detection of Pneumothorax Compared with Chest X-Ray and Computed Tomography Scan

Pneumothorax after trauma can be a life threatening injury and its care requires expeditious and accurate diagnosis and possible intervention. We performed a prospective, single blinded study with convenience sampling at a Level I trauma center comparing thoracic ultrasound with chest X-ray and CT scan in the detection of traumatic pneumothorax. Trauma patients that received a thoracic ultrasound, chest X-ray, and chest CT scan were included in the study. The chest X-rays were read by a radiologist who was blinded to the thoracic ultrasound results. Then both were compared with CT scan results. One hundred and twenty-five patients had a thoracic ultrasound performed in the 24-month period. Forty-six patients were excluded from the study due to lack of either a chest X-ray or chest CT scan. Of the remaining 79 patients there were 22 positive pneumothorax found by CT and of those 18 (82%) were found on ultrasound and 7 (32%) were found on chest X-ray. The sensitivity of thoracic ultrasound was found to be 81.8 per cent and the specificity was found to be 100 per cent. The sensitivity of chest X-ray was found to be 31.8 per cent and again the specificity was found to be 100 per cent. The negative predictive value of thoracic ultrasound for pneumothorax was 0.934 and the negative predictive value for chest X-ray for pneumothorax was found to be 0.792. We advocate the use of chest ultrasound for detection of pneumothorax in trauma patients.

Criteria for the selective use of chest computed tomography in blunt trauma patients

PURPOSE

The purpose of this study was to derive parameters that predict which high-energy blunt trauma patients should undergo computed tomography (CT) for detection of chest injury.

METHODS

This observational study prospectively included consecutive patients (>or=16 years old) who underwent multidetector CT of the chest after a high-energy mechanism of blunt trauma in one trauma centre.

RESULTS

We included 1,047 patients (median age, 37; 70% male), of whom 508 had chest injuries identified by CT. Using logistic regression, we identified nine predictors of chest injury presence on CT (age >or=55 years, abnormal chest physical examination, altered sensorium, abnormal thoracic spine physical examination, abnormal chest conventional radiography (CR), abnormal thoracic spine CR, abnormal pelvic CR or abdominal ultrasound, base excess <-3 mmol/l and haemoglobin <6 mmol/l). Of 855 patients with >or=1 positive predictors, 484 had injury on CT (95% of all 508 patients with injury). Of all 192 patients with no positive predictor, 24 (13%) had chest injury, of whom 4 (2%) had injuries that were considered clinically relevant.

CONCLUSION

Omission of CT in patients without any positive predictor could reduce imaging frequency by 18%, while most clinically relevant chest injuries remain adequately detected.

Focused assessment with sonography for trauma: the FAST scan

Focused assessment with sonography for trauma or focused abdominal sonography for trauma — the FAST scan, has become a useful modality for the initial evaluation of patients with blunt abdominal trauma. The technique is used to identify free fluid in the abdomen and pelvis and to detect the presence of a pericardial effusion. FAST can be performed by any trained individual, not necessarily a sonographer or radiologist, aiding in the immediate availability of this technique in the emergency situation. We will discuss the applications and sensitivity of this technique in trauma and review the potential pitfalls and limitations which need to be understood if this technique is to be safely applied. The use of FAST for the detection of pneumothoraces in trauma and other advances in FAST scanning, such as scoring systems and paediatric FAST are also reviewed.

Current Role of Emergency US in Patients with Major Trauma

In patients with major trauma, focused abdominal ultrasonography (US) often is the initial imaging examination. US is readily available, requires minimal preparation time, and may be performed with mobile equipment that allows greater flexibility in patient positioning than is possible with other modalities. It also is effective in depicting abnormally large intraperitoneal collections of free fluid, which are indirect evidence of a solid organ injury that requires immediate surgery. However, because US has poor sensitivity for the detection of most solid organ injuries, an initial survey with US often is followed by a more thorough examination with multidetector computed tomography (CT). The initial US examination is generally performed with a FAST (focused assessment with sonography in trauma) protocol. Speed is important because if intraabdominal bleeding is present, the probability of death increases by about 1% for every 3 minutes that elapses before intervention. Typical sites of fluid accumulation in the presence of a solid organ injury are the Morison pouch (liver laceration), the pouch of Douglas (intraperitoneal rupture of the urinary bladder), and the splenorenal fossa (splenic and renal injuries). FAST may be used also to exclude injuries to the heart and pericardium but not those to the bowel, mesentery, and urinary bladder, a purpose for which multidetector CT is better suited. If there is time after the initial FAST survey, the US examination may be extended to extra-abdominal regions to rule out pneumothorax or to guide endotracheal intubation, vascular puncture, or other interventional procedures.

Pre-existing cirrhosis is associated with increased mortality of traumatic patients: Analysis of cases from a trauma center in East China

AIM: To determine the impact of cirrhosis on trauma patients and define the factors predicting death.

METHODS: The data on patients admitted to the trauma center from January 2000-2005 were studied retrospectively. The clinical variables were recorded and compared to identify the factors differentiating cirrhotic trauma survivors from non survivors. Child's classification criteria were derived from the reviewed charts of cirrhotic trauma patients to evaluate their predictive value in cirrhotic trauma. Trauma registry was also used to generate a trauma control group by matching for age, sex, abbreviated injury score (AIS) over the same period of time. The outcome variables compared were mortality rate, time of ICU and hospital stay. Results were expressed as mean ± SD. These data were analyzed by SPSS.11.0 statistical software. Univariate analysis was performed to identify significant medical factors for survivor and non survivors subjected to chi-square test. Fisher's exact test and Student's t test were performed to determine the statistical difference between cirrhotic and control groups. P < 0.05 was considered statistically significant.

RESULTS: Poor prognosis of traum patients was associated with one or more of the following findings: ascitcs, hyperbilirubinemia (more than 2 mg/dL), hypoalbuminemia (less than 3.5 mg/dL), and prolonged prothrombin time (more than 12.5 seconds). Although Child's classification was used to predict the outcome in cirrhotic patients undergoing portacaval shunt procedures, no significant difference was found in mortality rate as a function of Child's classification.

CONCLUSION: Cirrhosis is associated with a higher mortality, a longer time of ICU and hospital stay of trauma patients. It seems that treatment of trauma patients with pre-existing severe liver disease is a challenge to surgeons.