Performance of abdominal ultrasonography in blunt trauma patients with out-of-hospital or emergency department hypotension

Progress in the Application of Portable Ultrasound Combined with Artificial Intelligence in Pre-Hospital Emergency and Disaster Sites

With the miniaturization of ultrasound and the development of artificial intelligence, its application in disaster scenes and pre-hospital emergency care has become more and more common. This study summarizes the literature on portable ultrasound in pre-hospital emergency and disaster scene treatment in the past decade and reviews the development and application of portable ultrasound. Portable ultrasound diagnostic equipment can be used to diagnose abdominal bleeding, limb fracture, hemopneumothorax, pericardial effusion, etc., based on which trauma can be diagnosed pre-hospital and provide guiding suggestions for the next triage and rescue; in early rescue, portable ultrasound can guide emergency operations, such as tracheal intubation, pericardial cavity puncture, and thoracic and abdominal puncture as well as improve the accuracy and timeliness of operation techniques. In addition, with the development of artificial intelligence (AI), AI-assisted diagnosis can improve the diagnosis level of ultrasound at disaster sites. The portable ultrasound diagnosis system equipped with an AI robotic arm can maximize the pre-screening classification and fast and concise diagnosis and treatment of batch casualties, thus providing a reliable basis for batch casualty classification and evacuation at disaster accident sites.

Traumatic hemorrhage and chain of survival

Trauma is the number one cause of death among Americans between the ages of 1 and 46 years, costing more than $670 billion a year. Following death related to central nervous system injury, hemorrhage accounts for the majority of remaining traumatic fatalities. Among those with severe trauma that reach the hospital alive, many may survive if the hemorrhage and traumatic injuries are diagnosed and adequately treated in a timely fashion. This article aims to review the recent advances in pathophysiology management following a traumatic hemorrhage as well as the role of diagnostic imaging in identifying the source of hemorrhage. The principles of damage control resuscitation and damage control surgery are also discussed. The chain of survival for severe hemorrhage begins with primary prevention; however, once trauma has occurred, prehospital interventions and hospital care with early injury recognition, resuscitation, definitive hemostasis, and achieving endpoints of resuscitation become paramount. An algorithm is proposed for achieving these goals in a timely fashion as the median time from onset of hemorrhagic shock and death is 2 h.

The Incremental Role of Multiorgan Point-of-Care Ultrasounds in the Emergency Setting

Point-of-care ultrasonography (POCUS) represents a goal-directed ultrasound examination performed by clinicians directly involved in patient healthcare. POCUS has been widely used in emergency departments, where US exams allow physicians to make quick diagnoses and to recognize early life-threatening conditions which require prompt interventions. Although initially meant for the real-time evaluation of cardiovascular and respiratory pathologies, its use has been extended to a wide range of clinical applications, such as screening for deep-vein thrombosis and trauma, abdominal ultrasonography of the right upper quadrant and appendix, and guidance for invasive procedures. Moreover, recently, bedside ultrasounds have been used to evaluate the fluid balance and to guide decongestive therapy in acutely decompensated heart failure. The aim of the present review was to discuss the most common applications of POCUS in the emergency setting.

Reevaluation of FAST Sensitivity in Pediatric Blunt Abdominal Trauma Patients: Should We Redefine the Qualitative Threshold for Significant Hemoperitoneum?

BACKGROUND

The utility of the focused assessment with sonography in trauma (FAST) examination in hemodynamically stable pediatric blunt abdominal trauma (BAT) patients is controversial.We report our 3-year experience with FAST performance to detect greater than physiologic amounts of intraperitoneal fluid after BAT.

METHODS

We performed a retrospective chart review of all FAST examinations performed from July 2015 to June 2018 at a level I pediatric trauma center. The main outcome of interest was the performance of a concerning FAST (cFAST) compared with a computed tomography scan diagnosis for greater than physiologic levels of free fluid (FF) and clinical follow-up. A cFAST was defined by the presence of any FF in the upper abdomen or by a moderate to large amount of FF present in the pelvis. The interobserver reliability of cFASTwas assessed with Cohen κ coefficient. Locations of FF were assessed.

RESULTS

A total of 448 FAST cases were eligible for review. The median age was 11 years with 64% male. Thirty-one FAST examinations (6.9%) were positive for some amount of FF; 18 (4.0%) were cFASTs. In the cFAST group, 11 patients (61%) were hemodynamically stable. The cFAST had a sensitivity of 89% (95% confidence interval [CI], 65%-99%), specificity of 99% (95% CI, 98%-100%), positive predictive value of 89% (95% CI, 67%-97%), and negative predictive value of 99% (95% CI, 98%-100%). The positive and negative likelihood ratios were 191 (95% CI, 47-769) and 0.11 (95% CI, 0.03-0.41). The κ coefficient for cFASTwas 0.72 with 86% agreement. Free fluid on cFAST cases was observed in the pelvis (78%), right upper quadrant (44%), and left upper quadrant (44%).

CONCLUSIONS

In pediatric BAT patients, a cFAST has acceptable sensitivity and remains a highly specific test to rule in greater than physiologic quantities of FF with confidence.

Performance of Focused Assessment with Sonography for Trauma Following Resuscitative Thoracotomy for Traumatic Cardiac Arrest

BACKGROUND

In patients undergoing resuscitative thoracotomy (RT) for traumatic cardiac arrest, focused assessment with sonography for trauma (FAST) is often used to look for intraperitoneal fluid. These findings can help determine whether abdominal exploration is warranted once return of spontaneous circulation is achieved; however, the diagnostic accuracy of FAST in this clinical scenario has yet to be evaluated. The purpose of this study was to assess the performance of FAST in identifying intra-abdominal hemorrhage following RT.

METHODS

We performed a 3-year retrospective study at a high-volume level 1 trauma center from 2014 to 2016. We included patients who underwent RT in the Emergency Department. All FAST examinations were performed by non-radiologists. Operative findings, computed tomography reports, diagnostic peritoneal aspirate (DPA) results, and autopsy findings were used as reference standards to calculate the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of the FAST.

RESULTS

A total of 158 patients met our inclusion criteria. The median age was 35 years (interquartile range [IQR]: 23-53), 86.1% were male, and 60.1% sustained blunt trauma. Most patients suffered severe injuries with a median injury severity score of 27 (IQR: 18-38). The sensitivity, specificity, PPV, NPV, and accuracy of FAST for identifying intra-abdominal hemorrhage were 66.0%, 84.8%, 68.6%, 83.2%, and 78.5%, respectively. Among the 107 patients with a negative FAST, 22 (20.6%) underwent DPA, which was positive in 5 patients.

CONCLUSIONS

FAST can be utilized in the diagnostic workup of trauma patients after RT. In patients with a positive FAST, exploratory laparotomy is warranted, whereas other diagnostic adjuncts such as DPA or mandatory abdominal exploration may be considered in patients with a negative FAST.

Increased body mass index does not impact the imaging quality of focused assessment with sonography in trauma

BACKGROUND

Many clinicians believe that a patient's body mass index (BMI) affects the likelihood of obtaining high quality ultrasound images.

OBJECTIVES

To assess the hypothesis that increased BMI is associated with worsening focused assessment with sonography in trauma (FAST) image quality.

METHODS

We conducted a retrospective single-center study of FAST examinations performed in a large academic emergency department (ED) with fellowship-trained emergency ultrasonography faculty performing quality assurance review.

RESULTS

Mean (SD) BMI was 28.0 (6.6) among the 302 included studies. The overall quality rating tended to decrease as BMI increased but did not achieve statistical significance in a univariable setting (P = .06) or after adjustment for age and sex (P = .06). Operators perception of image adequacy was largely unaffected by BMI, with the exception of the pericardial view.

CONCLUSION

This study did not identify a statistically significant difference in FAST quality with increased BMI. This result may help assuage clinician concerns about ultrasonography for patients in the ED.

Diagnostic accuracy of eFAST in the trauma patient: a systematic review and meta-analysis

Objectives

Performing an extended Focused Assessment with Sonography in Trauma (eFAST) exam is common practice in the initial assessment of trauma patients. The objective of this study was to systematically review the published literature on diagnostic accuracy of all components of the eFAST exam.

Methods

We searched Medline and Embase from inception through October 2018, for diagnostic studies examining the sensitivity and specificity of the eFAST exam. After removal of duplicates, 767 records remained for screening, of which 119 underwent full text review. Meta-DiSc™ software was used to create pooled sensitivities and specificities for included studies. Study quality was assessed using the Quality in Prognostic Studies (QUADAS-2) tool.

Results

Seventy-five studies representing 24,350 patients satisfied our selection criteria. Studies were published between 1989 and 2017. Pooled sensitivities and specificities were calculated for the detection of pneumothorax (69% and 99% respectively), pericardial effusion (91% and 94% respectively), and intra-abdominal free fluid (74% and 98% respectively). Sub-group analysis was completed for detection of intra-abdominal free fluid in hypotensive (sensitivity 74% and specificity 95%), adult normotensive (sensitivity 76% and specificity 98%) and pediatric patients (sensitivity 71% and specificity 95%).

Conclusions

Our systematic review and meta-analysis suggests that e-FAST is a useful bedside tool for ruling in pneumothorax, pericardial effusion, and intra-abdominal free fluid in the trauma setting. Its usefulness as a rule-out tool is not supported by these results.

Too fast, or not fast enough? The FAST exam in patients with non-compressible torso hemorrhage

BACKGROUND

Focused assessment with sonography for trauma (FAST) performance metrics are unknown in patients with non-compressible torso hemorrhage (NCTH).

METHODS

Retrospective review of a dedicated NCTH database from four level 1 trauma centers (2008-2012). NCTH was defined as (1) named axial torso vessel disruption; (2) AIS chest or abdomen >2 with shock (base deficit < -4) or truncal operation in ≤ 90 min; or (3) pelvic fracture with ring disruption. Patients were grouped by cavity of hemorrhage source and by shock (SBP ≤ 90).

RESULTS

274 patients had a FAST prior to diagnosis of NCTH. FAST was positive in 51% of patients with abdominal/pelvic hemorrhage for a false negative rate (FNR) of 49%. FNR was higher for pelvic (61%) versus abdominal (43%) sources (p = 0.02). There was no difference between FAST negative or positive patients for ISS, shock, length of stay, or mortality (all p = NS). FNR was not improved among the subgroup of NCTH patients with shock (p = NS).

CONCLUSION

FAST identified abdominal/pelvic hemorrhage in approximately half of NCTH patients, and this was not improved among patients presenting with shock.

The focused assessment with sonography in trauma (FAST) in hypotensive injured patients frequently fails to identify the need for laparotomy: a multi-institutional pragmatic study

Background

The ability of focused assessment with sonography for trauma (FAST) to detect clinically significant hemorrhage in hypotensive injured patients remains unclear. We sought to describe the sensitivity and specificity of FAST using findings at laparotomy as the confirmatory test.

Methods

Patients from the Prospective Observational Multicenter Major Trauma Transfusion (PROMMTT) study that had a systolic blood pressure < 90mm Hg and underwent FAST were analysed. Results were compared with findings at laparotomy. A therapeutic laparotomy (T-LAP) was defined as an abdominal operation within 6 hours in which a definitive procedure was performed. The sensitivity and specificity of FAST were calculated.

Results

The cohort included 317 patients that underwent FAST (108 positive, 209 negative). T-LAP was performed in 69% (n=75) of FAST(+) patients and 22% (n=48) of FAST(−) patients. FAST had a sensitivity of 62% and specificity of 83%.

Conclusions

In our multicenter cohort, 22% of FAST(−) patients underwent T-LAP within 6 hours of admission. In hypotensive patients with a negative FAST, clinicians should still maintain a high index of suspicion for significant abdominal hemorrhage.

Level of evidence

Level IV.

Effect of Abdominal Ultrasound on Clinical Care, Outcomes, and Resource Use Among Children With Blunt Torso Trauma: A Randomized Clinical Trial

IMPORTANCE

The utility of the focused assessment with sonography for trauma (FAST) examination in children is unknown.

OBJECTIVE

To determine if the FAST examination during initial evaluation of injured children improves clinical care.

DESIGN, SETTING, AND PARTICIPANTS

A randomized clinical trial (April 2012-May 2015) that involved 975 hemodynamically stable children and adolescents younger than 18 years treated for blunt torso trauma at the University of California, Davis Medical Center, a level I trauma center.

INTERVENTIONS

Patients were randomly assigned to a standard trauma evaluation with the FAST examination by the treating ED physician or a standard trauma evaluation alone.

MAIN OUTCOMES AND MEASURES

Coprimary outcomes were rate of abdominal computed tomographic (CT) scans in the ED, missed intra-abdominal injuries, ED length of stay, and hospital charges.

RESULTS

Among the 925 patients who were randomized (mean [SD] age, 9.7 [5.3] years; 575 males [62%]), all completed the study. A total of 50 patients (5.4%, 95% CI, 4.0% to 7.1%) were diagnosed with intra-abdominal injuries, including 40 (80%; 95% CI, 66% to 90%) who had intraperitoneal fluid found on an abdominal CT scan, and 9 patients (0.97%; 95% CI, 0.44% to 1.8%) underwent laparotomy. The proportion of patients with abdominal CT scans was 241 of 460 (52.4%) in the FAST group and 254 of 465 (54.6%) in the standard care-only group (difference, -2.2%; 95% CI, -8.7% to 4.2%). One case of missed intra-abdominal injury occurred in a patient in the FAST group and none in the control group (difference, 0.2%; 95% CI, -0.6% to 1.2%). The mean ED length of stay was 6.03 hours in the FAST group and 6.07 hours in the standard care-only group (difference, -0.04 hours; 95% CI, -0.47 to 0.40 hours). Median hospital charges were $46 415 in the FAST group and $47 759 in the standard care-only group (difference, -$1180; 95% CI, -$6651 to $4291).

CONCLUSIONS AND RELEVANCE

Among hemodynamically stable children treated in an ED following blunt torso trauma, the use of FAST compared with standard care only did not improve clinical care, including use of resources; ED length of stay; missed intra-abdominal injuries; or hospital charges. These findings do not support the routine use of FAST in this setting.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01540318.

Senior general surgery residents can be trained to perform focused assessment with sonography for trauma patients accurately

PURPOSES

Researchers studying trauma have found that physicians are able to perform a focused assessment with sonography for trauma (FAST) with minimal training and achieve ideal accuracy. However, there are currently no consensus or standard guidelines regarding the performance of this assessment. The aim of our study was to clarify the value of FAST performed by well-qualified senior general surgery residents in cases of suspected blunt abdominal trauma, which presents an important diagnostic problem in emergency departments.

METHODS

This was a retrospective study in the emergency department (ED) of our hospital performed from January 2011 to September 2013. Patients were included if they (1) had undergone a FAST examination performed by qualified residents and (2) had received subsequent formal radiographic or surgical evaluations. The results were compared against subsequent surgical findings or formal Department of Radiology reference standards.

RESULTS

Among the 438 patients enrolled, false-negative results were obtained in 8 and false-positive results in 5. Only one patient was missed and required laparotomy to repair a small intestine perforation. The sensitivity and specificity were 87 and 99%, respectively; the accuracy was 97%.

CONCLUSIONS

Senior general surgery residents can be trained to perform accurate FAST examinations on trauma patients.

Should we perform a FAST exam in haemodynamically stable patients presenting after blunt abdominal injury: a retrospective cohort study

Background

Focussed Assessment with Sonography for Trauma (FAST) is a bedside ultrasonography technique used to detect free intraperitoneal fluid in patients presenting with blunt abdominal trauma (BAT) in the emergency department.

Methods

In this retrospective cohort study we investigated the potential of FAST as a risk stratification instrument in haemodynamically (HD) stable patients presenting after BAT by establishing the association between the FAST exam result and final outcome. An adverse outcome was defined in this context as the need for either a laparoscopy/laparotomy or an angiographic embolization or death due to abdominal injuries).

Results

A total of 421 patients with BAT were included, of which nine had an adverse outcome (2%). FAST was negative in 407 patients. Six of them turned out to have free intraperitoneal fluid (sensitivity 67 [41–86]%). FAST was positive in 14 patients, 12 of whom had free intraperitoneal fluid (specificity 99 [98–100]%). A positive FAST (positive likelihood ratio 34.3 [15.1–78.5]) was stronger associated with an adverse outcome than Injury Severity Score (ISS) or any individual clinical- or biochemical variables measured at presentation in the ED.

Discussion

The FAST exam can provide valuable prognostic information at minimal expenses during the early stages of resuscitation in haemodynamically stable patients presenting with BAT.

Conclusions

FAST exam should not be omitted in patients with BAT.

Electronic supplementary material

The online version of this article (doi:10.1186/s13049-016-0342-0) contains supplementary material, which is available to authorized users.

Sports Ultrasound: Applications Beyond the Musculoskeletal System

BACKGROUND

Traditionally, ultrasound has been used to evaluate musculoskeletal injuries in athletes; however, ultrasound applications extend well beyond musculoskeletal conditions, many of which are pertinent to athletes.

EVIDENCE ACQUISITION

Articles were identified in PubMed using the search terms ultrasound, echocardiogram, preparticipation physical examination, glycogen, focused assessment with sonography of trauma, optic nerve, and vocal cord dysfunction. No date restrictions were placed on the literature search.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

Several potential applications of nonmusculoskeletal ultrasound in sports medicine are presented, including extended Focused Assessment with Sonography for Trauma (eFAST), limited echocardiographic screening during preparticipation physical examinations, assessment of muscle glycogen stores, optic nerve sheath diameter measurements in athletes with increased intracranial pressure, and assessment of vocal cord dysfunction in athletes.

CONCLUSION

Ultrasound can potentially be used to assist athletes with monitoring their muscle glycogen stores and the diagnosis of multiple nonmusculoskeletal conditions within sports medicine.

Ultrasonography in the emergency department

Point-of-care ultrasonography (POCUS) is a useful imaging technique for the emergency medicine (EM) physician. Because of its growing use in EM, this article will summarize the historical development, the scope of practice, and some evidence supporting the current applications of POCUS in the adult emergency department. Bedside ultrasonography in the emergency department shares clinical applications with critical care ultrasonography, including goal-directed echocardiography, echocardiography during cardiac arrest, thoracic ultrasonography, evaluation for deep vein thrombosis and pulmonary embolism, screening abdominal ultrasonography, ultrasonography in trauma, and guidance of procedures with ultrasonography. Some applications of POCUS unique to the emergency department include abdominal ultrasonography of the right upper quadrant and appendix, obstetric, testicular, soft tissue/musculoskeletal, and ocular ultrasonography. Ultrasonography has become an integral part of EM over the past two decades, and it is an important skill which positively influences patient outcomes.

The utility of FAST for initial abdominal screening of major pelvic fracture patients

BACKGROUND

Focused Assessment with Sonography for Trauma (FAST) is widely used in pelvic fracture patients. We examined the performance of FAST for detecting hemoperitoneum and predicting the need for intra-abdominal hemorrhage control in major pelvic fracture patients.

METHODS

A 5-year retrospective study of major pelvic fracture patients was performed. The presence of hemoperitoneum was confirmed on CT or at laparotomy. The need for hemorrhage control was defined as requiring a surgical or radiological intervention for intra-abdominal bleeding. Hemorrhagic shock (HS) patients had a systolic blood pressure ≤ 90 mmHg or base deficit of ≥ 6 mEq/L on admission.

RESULTS

A total of 120 patients were included, 42 (35 %) of which had any hemoperitoneum and 21 (18 %) had a moderate-large amount. The sensitivity, specificity, and positive and negative predictive values of FAST for any hemoperitoneum were 64, 94, 84, and 83 % and for a moderate-large amount they were 86, 86, 56, and 97 %. In HS patients the indices were 68, 93, 88, and 78 % for any hemoperitoneum and 79, 83, 65, and 91 % for a moderate-large amount. For the need for hemorrhage control, FAST had a positive predictive value of 50 % (16/32) in all and 71 % (12/17) in HS patients. The negative predictive value was 99 % (87/88) in all and 97 % (31/32) in HS patients.

CONCLUSION

FAST had a good to excellent diagnostic accuracy, depending on the size of hemoperitoneum. A positive FAST result (even in HS patients) does not reliably predict the need for immediate intra-abdominal hemorrhage control but a negative FAST result renders the need for an intervention highly unlikely.

Ultrasonographic diagnosis of abdominal free fluid: accuracy comparison of emergency physicians and radiologists

OBJECTIVE

Blunt abdominal trauma is a diagnostic challenge for emergency physicians and ultrasonography is one of the diagnostic tools used in this type of injuries. The aim of this study was to evaluate the diagnostic value of ultrasonographies performed by emergency physicians and radiologists.

METHODS

This prospective diagnostic study was performed in the emergency departments of two trauma centers in Iran during a period of 12 months. The subjects were all patients with blunt abdominal trauma that were candidated for abdominopelvic computed tomography (CT) scanning in our emergency departments. The results of focused assessment with sonography for trauma (FAST) performed by emergency physicians and radiologists were compared blindly with the results of CT scans performed by radiologists. The sensitivity, specificity, and predictive values of diagnosis for different abdominal anatomic areas were calculated.

RESULTS

In total, 450 patients undergoing FAST and CT scanning were studied. The sensitivity of radiologists' diagnoses for Morison's, splenorenal, perivesical, and pleural effusion areas were, respectively, 88.0, 70.0, 38.0, and 30.0 %. The corresponding values for emergency physicians' diagnoses were, respectively, 82.0, 60.0, 28.0, and 30.0 %. The specificity of radiologists' diagnoses in the mentioned areas were, respectively, 98.9, 100, 93.1, and 100 %, and for emergency physicians, they were, respectively, 98.9, 100, 96.0, and 100 %.

CONCLUSION

Emergency physicians showed a promising performance in applying FAST in blunt abdominal trauma. The specificity of ultrasonographic diagnosis in the emergency physicians group and the radiologists group were comparable, while radiologists showed a higher performance regarding the sensitivity of the ultrasonographic diagnosis.

Blunt abdominal trauma patients are at very low risk for intra-abdominal injury after emergency department observation

Introduction

Patients are commonly admitted to the hospital for observation following blunt abdominal trauma (BAT), despite initially negative emergency department (ED) evaluations. With the current use of screening technology, such as computed tomography (CT) of the abdomen and pelvis, ultrasound, and laboratory evaluations, it is unclear which patients require observation. The objective of this study was to determine the prevalence of intra-abdominal injury (IAI) and death in hemodynamically normal and stable BAT patients with initially negative ED evaluations admitted to an ED observation unit and to define a low-risk subgroup of patients and assess whether they may be discharged without abdominal/pelvic CT or observation.

Methods

This was a retrospective cohort study performed at an urban level 1 trauma center and included all BAT patients admitted to an ED observation unit as part of a BAT key clinical pathway. All were observed for at least 8 hours as part of the key clinical pathway, and only minors and pregnant women were excluded. Outcomes included the presence of IAI or death during a 40-month follow-up period. Prior to data collection, low-risk criteria were defined as no intoxication, no hypotension or tachycardia, no abdominal pain or tenderness, no hematuria, and no distracting injury. To be considered low risk, patients needed to meet all low-risk criteria.

Results

Of the 1,169 patients included over the 2-year study period, 29% received a CT of the abdomen and pelvis, 6% were admitted to the hospital from the observation unit for further management, 0.4% (95% confidence interval [CI], 0.1%–1%) were diagnosed with IAI, and 0% (95% CI, 0%–0.3%) died. Patients had a median combined ED and observation length of stay of 9.5 hours. Of the 237 (20%) patients who met low-risk criteria, 7% had a CT of the abdomen and pelvis and 0% (95% CI, 0%–1.5%) were diagnosed with IAI or died.

Conclusion

Most BAT patients who have initially negative ED evaluations are at low risk for IAI but still require some combination of observation and CT. A subgroup of BAT patients may be safely discharged without CT or observation after the initial evaluation.

False-negative FAST examination: associations with injury characteristics and patient outcomes

STUDY OBJECTIVE

Focused assessment with sonography in trauma (FAST) is widely used for evaluating patients with blunt abdominal trauma; however, it sometimes produces false-negative results. Presenting characteristics in the emergency department may help identify patients at risk for false-negative FAST result or help the physician predict injuries in patients with a negative FAST result who are unstable or deteriorate during observation. Alternatively, false-negative FAST may have no clinical significance. The objectives of this study are to estimate associations between false-negative FAST results and patient characteristics, specific abdominal organ injuries, and patient outcomes.

METHODS

This was a retrospective cohort study including consecutive patients who presented to an urban Level I trauma center between July 2005 and December 2008 with blunt abdominal trauma, a documented FAST, and pathologic free fluid as determined by computed tomography, diagnostic peritoneal lavage, laparotomy, or autopsy. Physicians blinded to the study purpose used standardized abstraction methods to confirm FAST results and the presence of pathologic free fluid. Multivariable modeling was used to assess associations between potential predictors of a false-negative FAST result and false-negative FAST result and adverse outcomes.

RESULTS

During the study period, 332 patients met inclusion criteria. Median age was 32 years (interquartile range 23 to 45 years), 67% were male patients, the median Injury Severity Score was 27 (interquartile range 17 to 41), and 162 (49%) had a false-negative FAST result. Head injury was positively associated with false-negative FAST result (odds ratio [OR] 4.9; 95% confidence interval [CI] 1.5 to 15.7), whereas severe abdominal injury was negatively associated (OR 0.3; 95% CI 0.1 to 0.5). Injuries to the spleen (OR 0.4; 95% CI 0.24 to 0.66), liver (OR 0.36; 95% CI 0.21 to 0.61), and abdominal vasculature (OR 0.17; 95% CI 0.07 to 0.38) were also negatively associated with false-negative FAST result. False-negative FAST result was not associated with mortality (OR 0.89; 95% CI 0.42 to 1.9), prolonged ICU length of stay (relative risk 0.88; 95% CI 0.69 to 1.12), or total hospital length of stay (relative risk 0.92; 95% CI 0.76 to 1.12). However, patients with false-negative FAST results were substantially less likely to require therapeutic laparotomy (OR 0.31; 95% CI 0.19 to 0.52).

CONCLUSION

Patients with severe head injuries and minor abdominal injuries were more likely to have a false-negative than true-positive FAST result. On the other hand, patients with spleen, liver, or abdominal vascular injuries are less likely to have false-negative FAST examination results. Adverse outcomes were not associated with false-negative FAST examination results, and in fact patients with false-negative FAST result were less likely to have a therapeutic laparotomy. Further studies are needed to assess the strength of these findings.

Clinical policy: critical issues in the evaluation of adult patients presenting to the emergency department with acute blunt abdominal trauma

This clinical policy from the American College of Emergency Physicians is an update of the 2004 clinical policy on the critical issues in the evaluation of adult patients presenting to the emergency department with acute blunt abdominal trauma. A writing subcommittee reviewed the literature as part of the process to develop evidence-based recommendations to address 4 key critical questions: (1) In a hemodynamically unstable patient with blunt abdominal trauma, is ultrasound the diagnostic modality of choice? (2) Does oral contrast improve the diagnostic performance of computed tomography (CT) in blunt abdominal trauma? (3) In a clinically stable patient with isolated blunt abdominal trauma, is it safe to discharge the patient after a negative abdominal CT scan result? (4) In patients with isolated blunt abdominal trauma, are there clinical predictors that allow the clinician to identify patients at low risk for adverse events who do not need an abdominal CT? Evidence was graded and recommendations were based on the available data in the medical literature related to the specific clinical question.

Ultrasound performed by radiologists-confirming the truth about FAST in trauma

BACKGROUND

For hemodynamically stable patients with suspected abdominal injuries, the diagnostic accuracy of computed tomographic scans remains unmatched. Focused assessment with sonography for trauma (FAST) is useful in trauma evaluation to identify intraabdominal fluid early in the unstable patient. In skilled hands, sensitivity is shown to be close to 100%. However, some recent studies have questioned its sensitivity in subgroups at risk of bleeding. In most studies, hemodynamic markers of instability have been limited to hypotension. The purpose of this study was to determine the sensitivity and specificity of initial FAST for detection of hemoperitoneum in the potentially unstable patient as judged by objective hemodynamic parameters available early during resuscitation.

METHODS

Prospective observational study at a major European trauma center. FAST was performed in trauma patients by the trauma team radiologist. The study population consisted of the subgroup deemed potentially unstable on arrival as defined by systolic blood pressure < or =90 mm Hg, pulse rate > or =120, or base deficit > or =8. Results were compared with one of the following reference standards: computed tomographic scan, diagnostic peritoneal lavage, exploratory laparotomy, or observation.

RESULTS

One hundred and four patients constituted the study group. There were 75 true-negative, 10 false-negative, 16 true-positive, and 3 false-positive FAST results. Sensitivity and specificity were 62% and 96%, positive and negative predictive values 84% and 89%, respectively, and overall accuracy was 88%.

CONCLUSION

A negative initial FAST in hemodynamically unstable patients, even in the hands of radiologists, cannot reliably exclude intraabdominal bleeding. These patients should undergo additional diagnostic tests to exclude intraperitoneal hemorrhage.

Clinical prediction rules for identifying adults at very low risk for intra-abdominal injuries after blunt trauma

STUDY OBJECTIVE

We derive and validate clinical prediction rules to identify adult patients at very low risk for intra-abdominal injuries after blunt torso trauma.

METHODS

We prospectively enrolled adult patients (>or=18 years old) after blunt torso trauma for whom diagnostic testing for intra-abdominal injury was performed. In the derivation phase, we used binary recursive partitioning to create a rule to identify patients with intra-abdominal injury who were undergoing acute intervention (including therapeutic laparotomy or angiographic embolization) and a separate rule for identifying patients with any intra-abdominal injury present. We considered only clinical variables readily available with acceptable interrater reliability. The prediction rules were then prospectively validated in a separate cohort of patients.

RESULTS

In the derivation phase, we enrolled 3,435 patients, including 311 (9.1%; 95% confidence interval [CI] 8.1% to 10.1%) with intra-abdominal injury and 109 (35.0%; 95% CI 29.7% to 40.6%) with intra-abdominal injury requiring acute intervention. In the validation study, we enrolled 1,595 patients, including 143 (9.0%; 95% CI 7.6% to 10.5%) with intra-abdominal injury. The derived rule for patients with intra-abdominal injuries who were undergoing acute intervention consisted of hypotension, Glasgow Coma Scale (GCS) score less than 14, costal margin tenderness, abdominal tenderness, hematuria level greater than or equal to 25 red blood cells/high powered field, and hematocrit level less than 30% and identified all 44 patients in the validation phase with intra-abdominal injury who were undergoing acute intervention (sensitivity 44/44, 100%; 95% CI 93.4% to 100%). The derived rule for the presence of any intra-abdominal injury consisted of GCS score less than 14, costal margin tenderness, abdominal tenderness, femur fracture, hematuria level greater than or equal to 25 red blood cells/high powered field, hematocrit level less than 30%, and abnormal chest radiograph result (pneumothorax or rib fracture). In the validation phase, the rule for any intra-abdominal injury present had the following test performance: sensitivity 137 of 143 (95.8%; 95% CI 91.1% to 98.4%), specificity 434 of 1,452 (29.9%; 95% CI 27.5% to 32.3%), and negative predictive value 434 of 440 (98.6%; 95% CI 97.1% to 99.5%).

CONCLUSION

These derived and validated clinical prediction rules can aid physicians in the evaluation of adult patients after blunt torso trauma. Patients without any of these variables are at very low risk for having intra-abdominal injury, particularly intra-abdominal injury requiring acute intervention, and are unlikely to benefit from abdominal computed tomography scanning.

Focused abdominal sonography for trauma in the emergency department for blunt abdominal trauma

BACKGROUND

Blunt abdominal trauma (BAT) is a diagnostic challenge to the emergency physician (EP). The introduction of bedside ultrasound provides another diagnostic tool for the EP to detect intra-abdominal injuries.

AIMS

To evaluate the performance of EP in a local emergency department in Hong Kong to perform the 'focused abdominal sonography for trauma' (FAST) in BAT patients.

METHODS

This was a retrospective cohort study including all the trauma team cases in a 36-month period in the emergency department of a public hospital in Hong Kong. The results of FAST scans were analyzed and compared with CT scans when the FAST was positive or followed by a period of clinical observation when the FAST was negative. Descriptive statistics and sensitivity, specificity, and predictive values were calculated.

RESULTS

There was a total of 273 cases, and FAST scans were performed in 242 cases. The sensitivity and specificity were 86% and 99%, respectively. The negative predictive value was 0.98, while the positive predictive value was 0.94. The overall accuracy was 97%.

CONCLUSIONS

The performance of the EP in using FAST scans in BAT patients was encouraging. The high specificity (99%), positive predictive value (0.98), and likelihood ratio for positive tests (86) make it a good 'rule in' tool for BAT patients. The high negative predictive value also makes the FAST scan a useful screening tool. However, ultrasound examination is operator dependent, and FAST scan has its own limitations. For negative FAST scan cases, we recommend a period of monitoring, serial FAST scans, or further investigations, such as CT scan or peritoneal lavage.

Advances in Abdominal Trauma

Emergency practitioners routinely encounter patients who suffer from abdominal trauma, be it blunt or penetrating. These injuries are often confounded by altered mental status, distracting injuries, or lack of historical information, and may present challenges in management. However, in the last several years new approaches to the diagnosis and management of abdominal trauma, including bedside ultrasound, newer generation computed tomography scans, laparoscopy, and the ability for selected nonoperative management expedite identification of life threatening injury and offer new options in treatment.

The Utility of Sonography for the Triage of Blunt Abdominal Trauma Patients to Exploratory Laparotomy

OBJECTIVE

The purpose of this study was to assess the utility of focused abdominal sonography for trauma (FAST) in the triage of hypotensive and normotensive blunt abdominal trauma patients to exploratory laparotomy.

MATERIALS AND METHODS

Data entered in a trauma registry database were retrospectively reviewed and were correlated with medical records, radiology reports, and surgical laparotomy reports. In the setting of blunt abdominal trauma, hypotensive patients were compared with normotensive patients who underwent FAST.

RESULTS

During the 6-year study period, 4,029 patients with blunt abdominal trauma underwent sonography, 122 of whom were hypotensive on arrival and underwent FAST. Of 87 hypotensive patients with positive findings on FAST, 69 (79%) were taken directly to exploratory laparotomy without the need for CT. In predicting the need for therapeutic laparotomy in hypotensive patients, the sensitivity of FAST was 85%, specificity was 60%, and accuracy was 77%. Of the 3,907 normotensive patients, 3,584 had negative FAST findings, whereas 323 had positive FAST findings. In normotensive patients, the sensitivity of FAST was 85%, specificity was 96%, and accuracy was 96%. In the combined patient population (all hypotensive and normotensive patients), 4,029 patients with blunt abdominal trauma underwent sonography: 3,619 had negative and 410 had positive FAST findings. In all patients regardless of blood pressure, the sensitivity of FAST was 85%, specificity was 96%, and accuracy was 95%.

CONCLUSION

Hypotensive patients screened in the emergency department with positive FAST findings may be triaged directly to therapeutic laparotomy, depending on the results of the sonography examination, without the need for CT.

Is Field Hypotension a Reliable Indicator of Significant Injury in Trauma Patients who are Normotensive on Arrival to the Emergency Department?

There is a subset of trauma patients who are hypotensive in the field but normotensive on arrival to the emergency department (ED). Our objective was to evaluate the presence, type, and severity of injuries in these patients. Data were retrospectively reviewed from patients treated at a level 1 trauma center over 1 year. Hypotension was defined as systolic blood pressure (SBP) less than 90 mm Hg. Forty-seven patients were included. The mechanism of injury was blunt in 37 patients and penetrating in 10. The average field SBP was 76 ± 11 mm Hg. The average SBP on arrival to the ED was 120 ± 19 mm Hg. The average injury severity score (ISS) was 16.3 ± 10.3 (range, 1–43). Twenty-four patients (51%) had significant injury (ISS ≥ 16). Nine patients (19%) had critical injury (ISS ≥ 25). Twenty-six patients (55%) required surgery, and 43 (91%) required ICU admission. Common injury sites included the head and neck (57%), thorax (44%), pelvis and extremities (40%), and abdomen (34%). Overall mortality was 10 per cent (n = 5). All patients that died had significant head and neck injuries (AIS ≥ 3). Field hypotension was a significant marker for potential serious internal injury requiring prompt diagnostic workup.