Anthony J. Medak

Prevalence and clinical import of thoracic injury identified by chest computed tomography but not chest radiography in blunt trauma: Multicenter prospective cohort study presented at the western regional society for academic emergency medicine meeting, March 2014, Irvine, CA; And the Society for Academic Emergency Medicine national meeting, May 2014, Dallas, TX.

STUDY OBJECTIVE Chest computed tomography (CT) diagnoses more injuries than chest radiography, so-called occult injuries. Wide availability of chest CT has driven substantial increase in emergency department use, although the incidence and clinical significance of chest CT findings have not been fully described. We determine the frequency, severity, and clinical import of occult injury, as determined by changes in management. These data will better inform clinical decisions, need for chest CT, and odds of intervention. METHODS Our sample included prospective data (2009 to 2013) on 5,912 patients at 10 Level I trauma center EDs with both chest radiography and chest CT at physician discretion. These patients were 40.6% of 14,553 enrolled in the parent study who had either chest radiography or chest CT. Occult injuries were pneumothorax, hemothorax, sternal or greater than 2 rib fractures, pulmonary contusion, thoracic spine or scapula fracture, and diaphragm or great vessel injury found on chest CT but not on preceding chest radiography. A priori, we categorized thoracic injuries as major (having invasive procedures), minor (observation or inpatient pain control >24 hours), or of no clinical significance. Primary outcome was prevalence and proportion of occult injury with major interventions of chest tube, mechanical ventilation, or surgery. Secondary outcome was minor interventions of admission rate or observation hours because of occult injury. RESULTS Two thousand forty-eight patients (34.6%) had chest injury on chest radiography or chest CT, whereas 1,454 of these patients (71.0%, 24.6% of all patients) had occult injury. Of these, in 954 patients (46.6% of injured, 16.1% of total), chest CT found injuries not observed on immediately preceding chest radiography. In 500 more patients (24.4% of injured patients, 8.5% of all patients), chest radiography found some injury, but chest CT found occult injury. Chest radiography found all injuries in only 29.0% of injured patients. Two hundred and two patients with occult injury (of 1,454, 13.9%) had major interventions, 343 of 1,454 (23.6%) had minor interventions, and 909 (62.5%) had no intervention. Patients with occult injury included 514 with pulmonary contusions (of 682 total, 75.4% occult), 405 with pneumothorax (of 597 total, 67.8% occult), 184 with hemothorax (of 230 total, 80.0% occult), those with greater than 2 rib fractures (n=672/1,120, 60.0% occult) or sternal fracture (n=269/281, 95.7% occult), 12 with great vessel injury (of 18 total, 66.7% occult), 5 with diaphragm injury (of 6, 83.3% occult), and 537 with multiple occult injuries. Interventions for patients with occult injury included mechanical ventilation for 31 of 514 patients with pulmonary contusion (6.0%), chest tube for 118 of 405 patients with pneumothorax (29.1%), and 75 of 184 patients with hemothorax (40.8%). Inpatient pain control or observation greater than 24 hours was conducted for 183 of 672 patients with rib fractures (27.2%) and 79 of 269 with sternal fractures (29.4%). Three of 12 (25%) patients with occult great vessel injuries had surgery. Repeated imaging was conducted for 50.6% of patients with occult injury (88.1% chest radiography, 11.9% chest CT, 7.5% both). For patients with occult injury, 90.9% (1,321/1,454) were admitted, with 9.1% observed in the ED for median 6.9 hours. Forty-four percent of observed patients were then admitted (4.0% of patients with occult injury). CONCLUSION In a more seriously injured subset of patients with blunt trauma who had both chest radiography and chest CT, occult injuries were found by chest CT in 71% of those with thoracic injuries and one fourth of all those with blunt chest trauma. More than one third of occult injury had intervention (37.5%). Chest tubes composed 76.2% of occult injury major interventions, with observation or inpatient pain control greater than 24 hours in 32.4% of occult fractures. Only 1 in 20 patients with occult injury was discharged home from the ED. For these patients with blunt trauma, chest CT is useful to identify otherwise occult injuries.

Derivation and validation of two decision instruments for selective chest CT in blunt trauma: a multicenter prospective observational study (NEXUS Chest CT).

Background Unnecessary diagnostic imaging leads to higher costs, longer emergency department stays, and increased patient exposure to ionizing radiation. We sought to prospectively derive and validate two decision instruments (DIs) for selective chest computed tomography (CT) in adult blunt trauma patients. Methods and Findings From September 2011 to May 2014, we prospectively enrolled blunt trauma patients over 14 y of age presenting to eight US, urban level 1 trauma centers in this observational study. During the derivation phase, physicians recorded the presence or absence of 14 clinical criteria before viewing chest imaging results. We determined injury outcomes by CT radiology readings and categorized injuries as major or minor according to an expert-panel-derived clinical classification scheme. We then employed recursive partitioning to derive two DIs: Chest CT-All maximized sensitivity for all injuries, and Chest CT-Major maximized sensitivity for only major thoracic injuries (while increasing specificity). In the validation phase, we employed similar methodology to prospectively test the performance of both DIs. We enrolled 11,477 patients—6,002 patients in the derivation phase and 5,475 patients in the validation phase. The derived Chest CT-All DI consisted of (1) abnormal chest X-ray, (2) rapid deceleration mechanism, (3) distracting injury, (4) chest wall tenderness, (5) sternal tenderness, (6) thoracic spine tenderness, and (7) scapular tenderness. The Chest CT-Major DI had the same criteria without rapid deceleration mechanism. In the validation phase, Chest CT-All had a sensitivity of 99.2% (95% CI 95.4%–100%), a specificity of 20.8% (95% CI 19.2%–22.4%), and a negative predictive value (NPV) of 99.8% (95% CI 98.9%–100%) for major injury, and a sensitivity of 95.4% (95% CI 93.6%–96.9%), a specificity of 25.5% (95% CI 23.5%–27.5%), and a NPV of 93.9% (95% CI 91.5%–95.8%) for either major or minor injury. Chest CT-Major had a sensitivity of 99.2% (95% CI 95.4%–100%), a specificity of 31.7% (95% CI 29.9%–33.5%), and a NPV of 99.9% (95% CI 99.3%–100%) for major injury and a sensitivity of 90.7% (95% CI 88.3%–92.8%), a specificity of 37.9% (95% CI 35.8%–40.1%), and a NPV of 91.8% (95% CI 89.7%–93.6%) for either major or minor injury. Regarding the limitations of our work, some clinicians may disagree with our injury classification and sensitivity thresholds for injury detection. Conclusions We prospectively derived and validated two DIs (Chest CT-All and Chest CT-Major) that identify blunt trauma patients with clinically significant thoracic injuries with high sensitivity, allowing for a safe reduction of approximately 25%–37% of unnecessary chest CTs. Trauma evaluation protocols that incorporate these DIs may decrease unnecessary costs and radiation exposure in the disproportionately young trauma population.

Integration of Ultrasound in Undergraduate Medical Education at the California Medical Schools A Discussion of Common Challenges and Strategies From the UMeCali Experience

Since the first medical student ultrasound electives became available more than a decade ago, ultrasound in undergraduate medical education has gained increasing popularity. More than a dozen medical schools have fully integrated ultrasound education in their curricula, with several dozen more institutions planning to follow suit. Starting in June 2012, a working group of emergency ultrasound faculty at the California medical schools began to meet to discuss barriers as well as innovative approaches to implementing ultrasound education in undergraduate medical education. It became clear that an ongoing collaborative could be formed to discuss barriers, exchange ideas, and lend support for this initiative. The group, termed Ultrasound in Medical Education, California (UMeCali), was formed with 2 main goals: to exchange ideas and resources in facilitating ultrasound education and to develop a white paper to discuss our experiences. Five common themes integral to successful ultrasound education in undergraduate medical education are discussed in this article: (1) initiating an ultrasound education program; (2) the role of medical student involvement; (3) integration of ultrasound in the preclinical years; (4) developing longitudinal ultrasound education; and (5) addressing competency.

Pulmonary contusion in the pan-scan era.

BACKGROUND Although pulmonary contusion (PC) is traditionally considered a major injury requiring intensive monitoring, more frequent detection by chest CT in blunt trauma evaluation may diagnose clinically irrelevant PC. OBJECTIVES We sought to determine (1) the frequency of PC diagnosis by chest CT versus chest X-ray (CXR), (2) the frequency of PC-associated thoracic injuries, and (3) PC patient clinical outcomes (mortality, length of stay [LOS], and need for mechanical ventilation), considering patients with PC seen on chest CT only (SOCTO) and isolated PC (PC without other thoracic injury). METHODS Focusing primarily on patients who had both CXR and chest CT, we conducted a pre-planned analysis of two prospectively enrolled cohorts with the following inclusion criteria: age >14 years, blunt trauma within 24h of emergency department presentation, and receiving CXR or chest CT during trauma evaluation. We defined PC and other thoracic injuries according to CT reports and followed patients through their hospital course to determine clinical outcomes. RESULTS Of 21,382 enrolled subjects, 8661 (40.5%) had both CXR and chest CT and 1012 (11.7%) of these had PC, making it the second most common injury after rib fracture. PC was SOCTO in 739 (73.0%). Most (73.5%) PC patients had other thoracic injury. PC patients had higher admission rates (91.9% versus 61.7%; mean difference 30.2%; 95% confidence interval [CI] 28.1-32.1%) and mortality (4.7% versus 2.0%: mean difference 2.8%; 95% CI 1.6-4.3%) than non-PC patients, but mortality was restricted to patients with other injuries (injury severity scores>10). Patients with PC SOCTO had low rates of associated mechanical ventilation (4.6%) and patients with isolated PC SOCTO had low mortality (2.6%), comparable to that of patients without PC. CONCLUSIONS PC is commonly diagnosed under current blunt trauma imaging protocols and most PC are SOCTO with other thoracic injury. Given that they are associated with low mortality and uncommon need for mechanical ventilation, isolated PC and PC SOCTO may be of limited clinical significance.

Sternal fracture in the age of pan-scan

STUDY OBJECTIVE Widespread chest CT use in trauma evaluation may increase the diagnosis of minor sternal fracture (SF), making former teaching about SF obsolete. We sought to determine: (1) the frequency with which SF patients are diagnosed by CXR versus chest CT under current imaging protocols, (2) the frequency of surgical procedures related to SF diagnosis, (3) SF patient mortality and hospital length of stay comparing patients with isolated sternal fracture (ISF) and sternal fracture with other thoracic injury (SFOTI), and (4) the frequency and yield of cardiac contusion (CC) workups in SF patients. METHODS We analyzed charts and data of all SF patients enrolled from January 2009 to May 2013 in the NEXUS Chest and NEXUS Chest CT studies, two multi-centre observational cohorts of blunt trauma patients who received chest imaging for trauma evaluation. RESULTS Of the 14,553 patients in the NEXUS Chest and Chest CT cohorts, 292 (2.0%) were diagnosed with SF, and 94% of SF were visible on chest CT only. Only one patient (0.4%) had a surgical procedure related to SF diagnosis. Cardiac contusion was diagnosed in 7 (2.4%) of SF patients. SF patient mortality was low (3.8%) and not significantly different than the mortality of patients without SF (3.1%) [mean difference 0.7%; 95% confidence interval (CI) -1.0 to 3.5%]. Only 2 SF patient deaths (0.7%) were attributed to a cardiac cause. SFOTI patients had longer hospital stays but similar mortality to patients with ISF (mean difference 0.8%; 95% CI -4.7% to 12.0). CONCLUSIONS Most SF are seen on CT only and the vast majority are clinically insignificant with no change in treatment and low associated mortality. Workup for CC in SF patients is a low-yield practice. SF diagnostic and management guidelines should be updated to reflect modern CT-driven trauma evaluation protocols.

Rib Fracture Diagnosis in the Panscan Era

Study objective With increased use of chest computed tomography (CT) in trauma evaluation, traditional teachings in regard to rib fracture morbidity and mortality may no longer be accurate. We seek to determine rates of rib fracture observed on chest CT only; admission and mortality of patients with isolated rib fractures, rib fractures observed on CT only, and first or second rib fractures; and first or second rib fracture–associated great vessel injury. Methods We conducted a planned secondary analysis of 2 prospectively enrolled cohorts of the National Emergency X‐Radiography Utilization Study chest studies, which evaluated patients with blunt trauma who were older than 14 years and received chest imaging in the emergency department. We defined rib fractures and other thoracic injuries according to CT reports and followed patients through their hospital course to determine outcomes. Results Of 8,661 patients who had both chest radiograph and chest CT, 2,071 (23.9%) had rib fractures, and rib fractures were observed on chest CT only in 1,368 cases (66.1%). Rib fracture patients had higher admission rates (88.7% versus 45.8%; mean difference 42.9%; 95% confidence interval [CI] 41.4% to 44.4%) and mortality (5.6% versus 2.7%; mean difference 2.9%; 95% CI 1.8% to 4.0%) than patients without rib fracture. The mortality of patients with rib fracture observed on chest CT only was not statistically significantly different from that of patients with fractures also observed on chest radiograph (4.8% versus 5.7%; mean difference –0.9%; 95% CI –3.1% to 1.1%). Patients with first or second rib fractures had significantly higher mortality (7.4% versus 4.1%; mean difference 3.3%; 95% CI 0.2% to 7.1%) and prevalence of concomitant great vessel injury (2.8% versus 0.6%; mean difference 2.2%; 95% CI 0.6% to 4.9%) than patients with fractures of ribs 3 to 12, and the odds ratio of great vessel injury with first or second rib fracture was 4.4 (95% CI 1.8 to 10.4). Conclusion Under trauma imaging protocols that commonly incorporate chest CT, two thirds of rib fractures were observed on chest CT only. Patients with rib fractures had higher admission rates and mortality than those without rib fractures. First or second rib fractures were associated with significantly higher mortality and great vessel injury.

Bilateral subdural hematomas after lumboperitoneal shunt placement.

BACKGROUND Lumboperitoneal shunts are commonly placed as treatment for a variety of conditions, and complications can be significant. OBJECTIVES We discuss a rare complication of these shunts, namely bilateral non-traumatic subdural hematoma formation. CASE REPORT A patient with a normal neurologic examination but severe nausea, weight loss, and dehydration presented 2 weeks after lumboperitoneal shunt placement for cryptococcal meningitis, and was found to have bilateral subdural hematomas. CONCLUSIONS Physicians should be aware of this potentially devastating complication of shunt placement so that prompt and appropriate treatment can be initiated.

Pneumothorax and Hemothorax in the Era of Frequent Chest Computed Tomography for the Evaluation of Adult Patients With Blunt Trauma

Study objective Although traditional teachings in regard to pneumothorax and hemothorax generally recommend chest tube placement and hospital admission, the increasing use of chest computed tomography (CT) in blunt trauma evaluation may detect more minor pneumothorax and hemothorax that might indicate a need to modify these traditional practices. We determine the incidence of pneumothorax and hemothorax observed on CT only and the incidence of isolated pneumothorax and hemothorax (pneumothorax and hemothorax occurring without other thoracic injuries), and describe the clinical implications of these injuries. Methods This was a planned secondary analysis of 2 prospective, observational studies of adult patients with blunt trauma, NEXUS Chest (January 2009 to December 2012) and NEXUS Chest CT (August 2011 to May 2014), set in 10 Level I US trauma centers. Participants’ inclusion criteria were older than 14 years, presentation to the emergency department (ED) within 6 hours of blunt trauma, and receipt of chest imaging (chest radiograph, chest CT, or both) during their ED evaluation. Exposure(s) (for observational studies) were that patients had trauma and chest imaging. Primary measures and outcomes included the incidence of pneumothorax and hemothorax observed on CT only versus on both chest radiograph and chest CT, the incidence of isolated pneumothorax and hemothorax (pneumothorax and hemothorax occurring without other thoracic injuries), and admission rates, hospital length of stay, mortality, and frequency of chest tube placement for these injuries. Results Of 21,382 enrolled subjects, 1,064 (5%) had a pneumothorax and 384 (1.8%) had a hemothorax. Of the 8,661 patients who received both a chest radiograph and a chest CT, 910 (10.5%) had a pneumothorax, with 609 (67%) observed on CT only; 319 (3.7%) had a hemothorax, with 254 (80%) observed on CT only. Of 1,117 patients with pneumothorax, hemothorax, or both, 108 (10%) had isolated pneumothorax or hemothorax. Patients with pneumothorax observed on CT only had a lower chest tube placement rate (30% versus 65%; difference in proportions [&Dgr;] ‐35%; 95% confidence interval [CI] –28% to 42%), admission rate (94% versus 99%; &Dgr; 5%; 95% CI 3% to 8%), and median length of stay (5 versus 6 days; difference 1 day; 95% CI 0 to 2 days) but similar mortality compared with patients with pneumothorax observed on chest radiograph and CT. Patients with hemothorax observed on CT had only a lower chest tube placement rate (49% versus 68%; &Dgr; ‐19%; 95% CI –31% to ‐5%) but similar admission rate, mortality, and median length of stay compared with patients with hemothorax observed on chest radiograph and CT. Compared with patients with other thoracic injury, those with isolated pneumothorax or hemothorax had a lower chest tube placement rate (20% versus 43%; &Dgr; ‐22%; 95% CI –30% to ‐13%), median length of stay (4 versus 5 days; difference ‐1 day; 95% CI –3 to 1 days), and admission rate (44% versus 97%; &Dgr; ‐53%; 95% CI –62% to ‐43%), with an admission rate comparable to that of patients without pneumothorax or hemothorax (49%). Conclusion Under current imaging protocols for adult blunt trauma evaluation, most pneumothoraces and hemothoraces are observed on CT only and few occur as isolated thoracic injury. The clinical implications (admission rates and frequency of chest tube placement) of pneumothorax and hemothorax observed on CT only and isolated pneumothorax or hemothorax are lower than those of patients with pneumothorax and hemothorax observed on chest radiograph and CT and of those who have other thoracic injury, respectively.

Trauma/Brief research reportRib Fracture Diagnosis in the Panscan Era

Study objective With increased use of chest computed tomography (CT) in trauma evaluation, traditional teachings in regard to rib fracture morbidity and mortality may no longer be accurate. We seek to determine rates of rib fracture observed on chest CT only; admission and mortality of patients with isolated rib fractures, rib fractures observed on CT only, and first or second rib fractures; and first or second rib fracture–associated great vessel injury. Methods We conducted a planned secondary analysis of 2 prospectively enrolled cohorts of the National Emergency X‐Radiography Utilization Study chest studies, which evaluated patients with blunt trauma who were older than 14 years and received chest imaging in the emergency department. We defined rib fractures and other thoracic injuries according to CT reports and followed patients through their hospital course to determine outcomes. Results Of 8,661 patients who had both chest radiograph and chest CT, 2,071 (23.9%) had rib fractures, and rib fractures were observed on chest CT only in 1,368 cases (66.1%). Rib fracture patients had higher admission rates (88.7% versus 45.8%; mean difference 42.9%; 95% confidence interval [CI] 41.4% to 44.4%) and mortality (5.6% versus 2.7%; mean difference 2.9%; 95% CI 1.8% to 4.0%) than patients without rib fracture. The mortality of patients with rib fracture observed on chest CT only was not statistically significantly different from that of patients with fractures also observed on chest radiograph (4.8% versus 5.7%; mean difference –0.9%; 95% CI –3.1% to 1.1%). Patients with first or second rib fractures had significantly higher mortality (7.4% versus 4.1%; mean difference 3.3%; 95% CI 0.2% to 7.1%) and prevalence of concomitant great vessel injury (2.8% versus 0.6%; mean difference 2.2%; 95% CI 0.6% to 4.9%) than patients with fractures of ribs 3 to 12, and the odds ratio of great vessel injury with first or second rib fracture was 4.4 (95% CI 1.8 to 10.4). Conclusion Under trauma imaging protocols that commonly incorporate chest CT, two thirds of rib fractures were observed on chest CT only. Patients with rib fractures had higher admission rates and mortality than those without rib fractures. First or second rib fractures were associated with significantly higher mortality and great vessel injury.

Rib Fracture Diagnosis in the Panscan Era - eScholarship

Study objective With increased use of chest computed tomography (CT) in trauma evaluation, traditional teachings in regard to rib fracture morbidity and mortality may no longer be accurate. We seek to determine rates of rib fracture observed on chest CT only; admission and mortality of patients with isolated rib fractures, rib fractures observed on CT only, and first or second rib fractures; and first or second rib fracture–associated great vessel injury. Methods We conducted a planned secondary analysis of 2 prospectively enrolled cohorts of the National Emergency X‐Radiography Utilization Study chest studies, which evaluated patients with blunt trauma who were older than 14 years and received chest imaging in the emergency department. We defined rib fractures and other thoracic injuries according to CT reports and followed patients through their hospital course to determine outcomes. Results Of 8,661 patients who had both chest radiograph and chest CT, 2,071 (23.9%) had rib fractures, and rib fractures were observed on chest CT only in 1,368 cases (66.1%). Rib fracture patients had higher admission rates (88.7% versus 45.8%; mean difference 42.9%; 95% confidence interval [CI] 41.4% to 44.4%) and mortality (5.6% versus 2.7%; mean difference 2.9%; 95% CI 1.8% to 4.0%) than patients without rib fracture. The mortality of patients with rib fracture observed on chest CT only was not statistically significantly different from that of patients with fractures also observed on chest radiograph (4.8% versus 5.7%; mean difference –0.9%; 95% CI –3.1% to 1.1%). Patients with first or second rib fractures had significantly higher mortality (7.4% versus 4.1%; mean difference 3.3%; 95% CI 0.2% to 7.1%) and prevalence of concomitant great vessel injury (2.8% versus 0.6%; mean difference 2.2%; 95% CI 0.6% to 4.9%) than patients with fractures of ribs 3 to 12, and the odds ratio of great vessel injury with first or second rib fracture was 4.4 (95% CI 1.8 to 10.4). Conclusion Under trauma imaging protocols that commonly incorporate chest CT, two thirds of rib fractures were observed on chest CT only. Patients with rib fractures had higher admission rates and mortality than those without rib fractures. First or second rib fractures were associated with significantly higher mortality and great vessel injury.