A prospective study of emergent abdominal sonography after blunt trauma

Focused abdominal US in patients with trauma

PURPOSE

To evaluate the accuracy of focused abdominal ultrasonography (US) in detecting abdominal injuries that require in-hospital patient treatment in the setting of blunt abdominal trauma.

MATERIALS AND METHODS

One thousand ninety patients with blunt abdominal trauma were assessed with focused abdominal US within 30 minutes of arrival at the hospital. Focused abdominal US results were positive if intra- or retroperitoneal fluid was detected. Patients with negative US results and no other major injuries were observed in the emergency department for 12 hours before discharge. Patients who deteriorated clinically after negative initial US underwent repeat US and/or emergency abdominopelvic computed tomography (CT). Patients with positive or indeterminate US results underwent emergency abdominopelvic CT.

RESULTS

Nine hundred seventy-four (89%) patients had negative focused abdominal US results; eight of these underwent CT. Sixty-six (6%) had positive US results. Four (0.4%) had false-negative and 19 (1.7%) had false-positive US results. Twenty-seven (2.5%) had indeterminate US results; of these, five (18.5%) had positive CT results. One hundred twenty-four (11.4%) required emergency CT. After indeterminate cases were excluded, focused abdominal US had 94% sensitivity, 98% specificity, 78% positive predictive value, 100% negative predictive value, and 95% accuracy.

CONCLUSION

Focused abdominal US has a high negative predictive value for major abdominal injury in patients with blunt abdominal trauma.

Trauma ultrasound feasibility during helicopter transport

OBJECTIVE

To evaluate the feasibility of performing a standard four-view focused abdominal sonography for trauma (FAST) examination during helicopter transport using a hand-carried ultrasound machine.

METHODS

In this prospective observational study, actual and simulated trauma patients were evaluated using the SonoSite 180 ultrasound machine by two air transport programs serving Level I trauma centers. FAST examinations were performed in flight by emergency medicine faculty, residents, flight nurses, and ultrasound technologists, who rated the difficulty posed by various factors using Likert scales (0 = not difficult to 5 = impossible). BK 117, Bell 230, and BO 105 medical helicopters flew in all aviating modes. Pilots were queried regarding avionics variations throughout the flights.

RESULTS

Ten flight sonographers performed 21 FAST examinations on 14 patients (five actual, nine simulated). The median Likert value for each parameter was 0 except for patient position, which was 1 (somewhat difficult). Interquartile ranges were 0-0 for vibration, bedding, IV catheters, monitor cables, and ventilator; 0-0.5 for backboard straps; and 0-1 for sunlight, patient position, spider straps, gurney straps, and clothing. Mean examination duration, was 3.0 minutes (range 1.5 to 5.5 minutes, SD 1.3). Pilots reported no effects on avionics in any flight mode.

CONCLUSION

The FAST examination using the SonoSite 180 in flight was rated by 10 evaluators to be performed easily. Examinations were conducted quickly and did not interfere with helicopter avionics. This digital ultrasound machine is the first one small enough to be used in most medical helicopters.

Comparison of US utilization and technical costs before and after establishment of 24-hour in-house coverage for US examinations

PURPOSE

To compare data regarding the cost and number of ultrasonographic (US) examinations performed for 6 months, before and after institution of 24-hour in-house sonographer coverage.

MATERIALS AND METHODS

Data for a 6-month period during which US services were provided by a sonographer on call from 11 PM to 7 AM were compared with data for a 6-month period during which a sonographer was in house during this shift.

RESULTS

With 11 PM to 7 AM on-call coverage, the sonographers performed 147 examinations in a 6-month period, an average of 0.81 examination per shift. After institution of in-house coverage for this shift, 792 US examinations were performed in 6 months, an average of 4.3 examinations per shift. The cost for 11 PM to 7 AM in-house sonographer coverage for 6 months was approximately $16,000 more than that for on-call coverage. This cost would be offset by revenues from one additional examination per night. The cost per examination for the 11 PM to 7 AM shift decreased from $124.70 to $43.33.

CONCLUSION

At the authors' institution, 24-hour in-house sonographer coverage resulted in additional cost, which was offset by revenues from additional examinations. There was nearly a fivefold increase in the number of US examinations performed per shift. These examinations were performed more expediently, enabling more rapid patient triage.

ED evaluation of the pediatric trauma patient by ultrasonography

The purpose of this study was to determine the accuracy of ultrasound examination of pediatric trauma patients by emergency physicians. Pediatric (age less than 18 years) trauma patients presenting to the emergency department of a level I trauma center were prospectively examined with bedside ultrasound during the secondary survey of their trauma resuscitation. Examinations were performed by emergency medicine residents and attending physicians who had completed an 8-hour course on trauma ultrasonography. Trauma physicians providing care to the patient were blinded to the results of the examination. In 47 children (median age 9 years) computed tomography of the abdomen/pelvis or laparotomy were also performed and served as gold standards to verify the presence or absence of free fluid in the abdomen. Sensitivity, specificity, and accuracy of the ultrasound examination for the detection of free fluid in the abdominal cavity was 75% (95% confidence interval [CI] 36% to 95%), 97% (95% CI 81% to 100%), and 92% (95% Cl 77% to 98%). Positive and negative predictive values were 90% (95% CI 46% to 100%) and 92% (95% CI 74% to 99%), respectively. Ultrasound examinations took an average of 7 minutes and 36 seconds, although this did not take into consideration delays created by interruptions for other diagnostic tests or procedures. An emergency physician and radiologist agreed on blinded interpretations of 83% of the examinations (kappa = 0.56). Bedside ultrasonography is a reliable and rapid method for screening traumatized children for the presence or absence of free fluid in the peritoneum even in the hands of novice sonographers.

Sonographic assessment of traumatic injury. Future developments

In all its forms and applications, sonography plays a significant role in the management of injured patients, from the emergency department to beyond hospital discharge. The use of new and existing sonographic technology will increase because sonographic imaging and measurements are generally less invasive; are inexpensive; use no ionizing radiation; and are portable, repeatable, and, in many instances, as accurate as the so-called "contemporary gold standards." The training and credentialing of physicians in sonography is in evolution and will be an increasingly important issue with more widespread use and broader applications. The future of sonography in trauma care in the next millennium is bright, and surgeons and surgical residents are encouraged to gain proficiency and learn about this new surgical frontier as it evolves.

Prospective evidence of the superiority of a sonography-based algorithm in the assessment of blunt abdominal injury

BACKGROUND

Although the routine use of FAST (focused assessment with sonography for trauma) in the evaluation of trauma victims is increasing, to our knowledge, a prospective comparison of contemporary adult trauma victims managed with and without FAST has not been reported in North America.

METHODS

Adult victims of blunt trauma for whom there was a suspicion of abdominal injury were managed with one of two diagnostic algorithms, FAST or no-FAST. The two algorithms were compared for diagnostic accuracy, cost, time, and delayed diagnoses.

RESULTS

Among 706 patients (mean Injury Severity Score, 23), 460 were managed with FAST and 246 with no-FAST. The two groups were similar with respect to age, Injury Severity Score, prehospital time, and mortality (p = not significant). There were 3 of 460 (0.7%) delayed diagnoses in the FAST group and 4 of 246 (1.6%) in the no-FAST group (p = not significant). The diagnostic accuracy for the FAST and no-FAST algorithms was 99% and 98%, respectfully. The FAST and no-FAST algorithms led to similar rates of laparotomy, 13% and 14%, respectfully, but nonoperative management was more common in the no-FAST group (p < 0.01). The mean diagnostic cost for the FAST algorithm was $156, compared with $540 with the no-FAST algorithm (p < 0.0001) and the mean time required for diagnostic work-up was 53 minutes with the FAST algorithm, compared with 151 minutes with the no-FAST algorithm (p < 0.0001).

CONCLUSION

This study has provided prospective evidence that a FAST-based algorithm for blunt abdominal injury was more rapid, less expensive, and as accurate as an algorithm that used computed tomography or diagnostic peritoneal lavage only. Trauma centers are encouraged to incorporate a FAST-based algorithm into their initial management of blunt trauma victims.

Hemoperitoneum as the sole indicator of abdominal visceral injuries: a potential limitation of screening abdominal US for trauma

PURPOSE

To determine, at screening ultrasonography, the prevalence, severity, and clinical outcome of clinically important abdominal visceral injuries, without associated hemoperitoneum, that result from blunt abdominal trauma.

MATERIALS AND METHODS

Computed tomography (CT) was performed at admission in 466 patients with visceral injury. A retrospective review was performed of findings from surgery and contrast material-enhanced spiral and conventional CT performed to verify abdominal visceral injuries in 467 (4%) of 11,188 patients with blunt trauma. These patients were admitted to a level 1 trauma center over 33 months to determine the presence of hemoperitoneum and to identify the grade of injury. Medical records of patients with abdominal visceral injury without hemoperitoneum were reviewed for the management required and for results of focused abdominal sonography for trauma (FAST).

RESULTS

A total of 575 abdominal visceral injuries were identified at CT and/or surgery. Findings of CT at admission (n = 156) and of surgery (n = 1) revealed no evidence of hemoperitoneum in 157 (34%) patients with abdominal visceral injury; 26 (17%) of whom also had negative FAST studies. Abdominal visceral injuries diagnosed in patients without hemoperitoneum included 57 (27%) of 210 splenic injuries, 71 (34%) of 206 hepatic injuries, 30 (48%) of 63 renal injuries, four (11%) of 35 mesenteric injuries, and two (29%) of seven pancreatic injuries. Surgical and/or angiographic intervention was required in 26 (17%) patients without hemoperitoneum.

CONCLUSION

Reliance on the presence of hemoperitoneum as the sole indicator of abdominal visceral injury limits the value of FAST as a screening diagnostic modality for patients who sustain blunt abdominal trauma.

An algorithm to reduce the incidence of false-negative FAST examinations in patients at high risk for occult injury. Focused Assessment for the Sonographic Examination of the Trauma patient

BACKGROUND

The Focused Assessment for the Sonographic Examination of the Trauma patient (FAST) sequentially surveys for the presence or absence of blood in dependent abdominal regions including the right upper quadrant, left upper quadrant, and the pelvis. But it does not readily identify intraparenchymal or retroperitoneal injuries, and a CT scan of the abdomen may be needed to reduce the incidence of missed injuries. We hypothesized that select patients who are considered high risk for occult injuries should undergo a CT scan of the abdomen when the FAST is negative so that occult injuries can be detected.

STUDY DESIGN

An algorithm was prospectively tested for the evaluation of select injured patients over a 3 1/2-year period. Entrance criteria included adult patients with a blunt mechanism of trauma, a negative FAST examination, and a spine fracture (with or without cord injury), or a pelvic fracture. Trauma team members performed the FAST on patients during the Advanced Trauma Life Support secondary survey. Data recorded included the patient's mechanism and type of injury, the results of the FAST and CT scan examinations, operative or postmortem findings or both, and patient outcomes. Patients with spine injuries were grouped according to spine level and the presence or absence of neurologic deficit. The patients with pelvic fractures were grouped according to the Young and Resnick classification.

RESULTS

One hundred two of 1,490 patients (6.8%) who had FAST examinations were entered into this study. Thirty-two patients (30.5%) had spine injuries, with only one false-negative ultrasound result. Seventy patients (68.6%) had pelvic fractures with 13 false-negative ultrasound results: 11 ring (9 from motor vehicle crashes, 2 from pedestrians struck), 1 acetabular, and 1 isolated pelvic fracture. Nine patients underwent nonoperative management for solid organ injuries, and 4 patients needed surgery.

CONCLUSIONS

Based on these preliminary data, we conclude that patients with pelvic ring-type fractures should have CT scans of the abdomen because of the higher yield for occult injuries.

Ultrasound in the ED: a different point of view

Many published papers report excellent sensitivity, specificity and accuracy when non-radiologists employ ultrasound (U/S) to detect free intraperitoneal fluid in cases of blunt abdominal trauma (BAT). In this setting, it is best to view the FAST (focused abdominal sonogram in trauma) as a noninvasive diagnostic peritoneal lavage (DPL): It tells us whether there is free intraperitoneal fluid but does not determine the specific parenchymal injury. In other words it is a screening tool.

Ultrasound: Impact on Diagnostic Peritoneal Lavage, Abdominal Computed Tomography, and Resident Training

Our objective was to determine the impact of abdominal ultrasound (US) on 1) the use of diagnostic peritoneal lavage (DPL) and abdominal computed tomography (ACT) for diagnosing blunt abdominal trauma (BAT) and on 2) surgical resident training. The study design was a retrospective chart review. Patients sustaining BAT who had ACT or DPL done during the 1-year period before the introduction of US (pre-US) were compared with those from a 1-year period beginning 6 months after US (post-US). Data collected included diagnostic modality, demographic data, mortality, associated injuries, length of stay, mechanism of injury, and number of exploratory laparotomies. Of 128 patients in the pre-US group, 35 patients (27%; P < 0.001) underwent DPL, 0 patients (0%; P < 0.001) received US, and 92 patients (72%) received ACT, with positive results for 31 patients (34%). Exploratory laparotomy was performed on 35 patients (27%) in the pre-US group. Of 140 patients in the post-US group, 8 patients (6%; P < 0.001) underwent DPL, 120 patients (85%; P < 0.001) received US, and 108 patients (77%) received ACT, with positive results for 44 patients (42%). Exploratory laparotomy was performed on 22 patients (15%; P < 0.001) in the post-US group. Resident experience with DPL before and after the introduction of US and availability of US for graduated residents was documented. Chi-square and Fisher's exact test were used for statistical analysis. Resident experience changed from 22 to 3 DPLs per year in the pre- and post-US groups, respectively. Ten per cent of graduating residents had US available for use after leaving this institution. US replaced DPL and resulted in slightly more positive ACT scans in assessing BAT at our institution. Paradoxically, only 10 per cent of graduating residents had US available after leaving this institution. Until the use of US for diagnosing BAT has widespread use in the community, we must question our adequacy of resident preparation for diagnosing BAT.

The role of ultrasound in patients with possible penetrating cardiac wounds: a prospective multicenter study

BACKGROUND

Ultrasound is quickly becoming part of the trauma surgeon's practice, but its role in the patient with a penetrating truncal injury is not well defined. The purpose of this study was to evaluate the accuracy of emergency ultrasound as it was introduced into five Level I trauma centers for the diagnosis of acute hemopericardium.

METHODS

Surgeons or cardiologists (four centers) and technicians (one center) performed pericardial ultrasound examinations on patients with penetrating truncal wounds. By protocol, patients with positive examinations underwent immediate operation. Vital signs, base deficit, time from examination to operation, operative findings, treatment, and outcome were recorded.

RESULTS

Pericardial ultrasound examinations were performed in 261 patients. There were 225 (86.2%) true-negative, 29 (11.1%) true-positive, 0 false-negative, and 7 (2.7%) false-positive examinations, resulting in sensitivity of 100%, specificity of 96.9%, and accuracy of 97.3%. The mean time from ultrasound to operation was 12.1+/-5 minutes.

CONCLUSION

Ultrasound should be the initial modality for the evaluation of patients with penetrating precordial wounds because it is accurate and rapid.

Focused Assessment with Sonography for Trauma (FAST): results from an international consensus conference

OBJECTIVE

To assemble an international panel of experts to develop consensus recommendations on selected important issues on the use of ultrasonography (US) in trauma care.

SETTING

R Adams Cowley Shock Trauma Center, University of Maryland Medical System, Baltimore, Md. The conference was held on December 4, 1997.

PARTICIPANTS

A committee of two co-directors and eight faculty members, in the disciplines of surgery and emergency medicine, representing four nations. Each faculty member had made significant contributions to the current understanding of US in trauma.

RESULTS

Six broad topics felt to be controversial or to have wide variation in practice were discussed using the ad hoc process: (1) US nomenclature and technique; (2) US for organ-specific injury; (3) US scoring systems; (4) the meaning of positive and negative US studies; (5) US credentialing issues; and (6) future applications of US. Consensus recommendations were made when unanimous agreement was reached. Majority viewpoints and minority opinions are presented for unresolved issues.

CONCLUSION

The consensus conference process fostered an international sharing of ideas. Continued communication is needed to advance the science and technology of US in trauma care.

Evaluation of the patient with blunt abdominal trauma: an evidence based approach

Patients with blunt abdominal trauma present a special challenge to the emergency physician. Physical examination is often unreliable, even if the patient is awake, and the frequent co-existence of head injury exacerbates this problem. This article examines the evidence basis of three diagnostic modalities in evaluating blunt abdominal trauma: DPL (the time-honored test); CT scanning (the current standard of care); and abdominal sonography (the emerging standard--especially for examination conducted in the trauma room). A proposed algorithm for the appropriate use of these modalities is also presented.

Early detection of hemoperitoneum by ultrasound examination of the right upper quadrant: a multicenter study

BACKGROUND

The focused assessment for the sonographic examination of the trauma patient (FAST) is a rapid diagnostic test that sequentially surveys for hemopericardium and then the right upper quadrant (RUQ), left upper quadrant (LUQ), and pelvis for hemoperitoneum in patients with potential truncal injuries. The sequence of the abdominal part of the examination, however, has yet to be validated. The objectives of this multicenter study were as follows: (1) to determine where hemoperitoneum is most frequently identified on positive FAST examinations; and (2) to determine if a relationship exists between that areas and the organs injured.

METHODS

Ultrasound registries from four Level I trauma centers identified patients who had true-positive FAST examinations. Demographic data, areas positive on the FAST, and organs injured were recorded; injuries were classified as multiple, single solid organ (liver or spleen), isolated hollow viscus, or retroperitoneal. Relationships between positive locations on the FAST examinations and the associations of organs injured to areas positive were assessed using McNamara's chi2 test; a p value < 0.05 was considered statistically significant.

RESULTS

The RUQ was the most common site where hemoperitoneum was detected, and this was statistically significant compared with either the LUQ or the pelvis. Also, statistically significant correlations (p < 0.001) were observed between positive RUQ areas on the FAST and multiple injuries, single solid organ (liver or spleen) injury, and retroperitoneal injuries.

CONCLUSION

Blood is most often found on the FAST in the RUQ area in patients with multiple intraperitoneal injuries or isolated injury to the liver, spleen, or retroperitoneum, but not when there is injury to a hollow viscus.

Surgeon-performed ultrasound for the assessment of truncal injuries: lessons learned from 1540 patients

OBJECTIVE

To determine the accuracy of the Focused Assessment for the Sonographic examination of the Trauma patient (FAST) when performed by trauma team members during a 3-year period, and to determine the clinical conditions in which the FAST is most accurate in the assessment of injured patients.

SUMMARY BACKGROUND DATA

The FAST is a rapid test that sequentially surveys the pericardial region for hemopericardium and then the right and left upper quadrants and pelvis for hemoperitoneum in patients with potential truncal injuries. The clinical conditions in which the FAST is most accurate in the assessment of injured patients have yet to be determined.

METHODS

FAST examinations were performed on patients with precordial or transthoracic wounds or blunt abdominal trauma. Patients with a positive ultrasound (US) examination for hemopericardium underwent immediate surgery, whereas those with a positive US for hemoperitoneum underwent a computed tomography scan (if they were hemodynamically stable) or immediate celiotomy (if they were hemodynamically unstable- blood pressure < or = 90 mmHg).

RESULTS

FAST examinations were performed in 1540 patients (1227 with blunt injuries, 313 with penetrating injuries). There were 1440 true-negative results, 80 true-positive results, 16 false-negative results, and 4 false-positive results; the sensitivity was 83.3%, the specificity 99.7%. US was most sensitive and specific for the evaluation of patients with precordial or transthoracic wounds (sensitivity 100%, specificity 99.3%) and hypotensive patients with blunt abdominal trauma (sensitivity 100%, specificity 100%).

CONCLUSIONS

US should be the initial diagnostic modality for the evaluation of patients with precordial wounds and blunt truncal injuries because it is rapid and accurate. Because of the high sensitivity and specificity of US in the evaluation of patients with precordial wounds and hypotensive patients with blunt torso trauma, immediate surgical intervention is justified when those patients have a positive US examination.

The indeterminate abdominal sonogram in multisystem blunt trauma

BACKGROUND

North American trauma centers are beginning to note the limitations of emergent torso sonography. The purpose of this prospective study was to evaluate the frequency, causes, associations, and sequelae of indeterminate (IND) sonograms in blunt trauma.

METHODS

Among adult blunt trauma patients assessed with screening torso sonography, clinician sonographers recorded the abdominal sonogram as positive, negative, or IND for free fluid. Patients with IND sonograms were further investigated with repeat sonography, computed tomography, or diagnostic peritoneal lavage.

RESULTS

Among 417 patients with blunt trauma (mean Injury Severity Score = 21) managed with sonography, there were 28 (6.7%) IND and 389 (93.3%) non-IND sonograms. Sonograms were IND because of patient factors in 71% (20 of 28) and because of operator factors in 29% (8 of 28). None of the 28 patients were managed with repeat sonography alone. All 4 diagnostic peritoneal lavage examinations gave negative results, whereas 8 of 23 computed tomographic scans were abnormal (6 of 8 patients underwent laparotomy). The mean time required for diagnostic workup was 117 minutes in the IND group and 48 minutes in the non-IND group (p < 0.001 in both cases).

CONCLUSION

This prospective study has demonstrated that IND sonograms are not common at our center (6.7%), are usually attributable to patient factors, and are associated with greater diagnostic time. Patients with IND sonograms require further investigation because they often have injuries requiring laparotomy.

Surgeon-performed ultrasound: its use in clinical practice

OBJECTIVE

To highlight areas where surgeon-performed ultrasound (US) is an effective diagnostic and therapeutic tool.

SUMMARY BACKGROUND DATA

The success of US in trauma and technologic advances have enhanced the interest and ability of surgeons to perform their own US examinations.

METHODS

General surgeons perform US examinations of the thyroid gland, breast, gastrointestinal tract, peritoneal cavity (laparoscopy), and vascular system. Essentials of these examinations are discussed and a plan for educating surgical residents in US is outlined.

RESULTS

Focused assessment for the sonographic examination of the trauma patient, or FAST, is replacing central venous pressure measurements to detect hemopericardium and diagnostic peritoneal lavage to detect hemoperitoneum. Bedside US can be used to detect a pleural effusion so well in critically ill patients that lateral decubitus x-rays are rarely needed. US-directed biopsy of breast lesions is a common office procedure. Laparoscopic US allows tumor staging without formal celiotomy, and many hepatic and pancreatic surgical procedures include US as an adjunct. Endoscopic and endorectal US have added a new dimension to the assessment of many gastrointestinal lesions. Color flow duplex imaging and endoluminal US have significantly expanded the diagnostic and therapeutic aspects of vascular imaging. The training program developed at Emory University and Grady Memorial Hospital is offered as a model for educating surgical residents in US techniques.

CONCLUSIONS

US is a valuable addition to the general surgeon's diagnostic armamentarium and is rapidly becoming an integral part of the surgeon's clinical practice.

Ultrasound as used in thoracoabdominal trauma

Because it is unique in being portable, rapid, and noninvasive, ultrasound is particularly suited to the trauma setting. When performed by the surgeon, it offers immediate feedback that can be incorporated into the management plan for the patient. Multiple studies in this area have now documented that surgeons can perform and interpret focused ultrasound examinations. Enthusiasm for surgeons as ultrasonographers will likely increase now that the Advanced Trauma Life Support Subcommittee of the American College of Surgeons has published an algorithm that includes ultrasound for the assessment of patients with blunt truncal injuries. As a rapid, sensitive, and specific diagnostic test for the detection of pericardial tamponade, hemothorax, and hemoperitoneum, ultrasound is now an integral part of the practice at many Level I trauma centers.

The history of ultrasound

Diagnostic medical ultrasound may have a brief history, but its roots date back to the early nineteenth century. From its modest beginnings in military institutions where ultrasound was used to examine pathologic specimens, to the routine evaluation of the fetus, injured patients, and those with cerebrovascular disease, ultrasound has secured a position as a key diagnostic test both currently and in the future. Its ability to diagnose valvular and congenital heart disease has reduced the need for invasive cardiac angiography with its attendant risks. Furthermore, endoluminal, transvaginal, transrectal, and transesophageal ultrasound have expanded physicians' diagnostic armamentarium and ability to "look inside" their patients. Notwithstanding all these advancements, ultrasound research and development continue to be fostered, and the ideas of today will be the technology of tomorrow (Fig. 5).

Swine and dynamic ultrasound models for trauma ultrasound testing of surgical residents

BACKGROUND

Trauma ultrasound workshops have been recommended for training surgical residents. We assessed the teaching effectiveness of the workshop, comparing swine and dynamic patient ultrasound models.

MATERIALS AND METHODS

MCQ exams on ultrasound physics and practical skills tests with and without pericardial or peritoneal fluid using four swines and eight dynamic patient ultrasound videos were used to compare pre- and postworkshop performance in 18 surgical residents (Group I) and a matched control group of 18 (Group II). Paired t tests and unpaired t tests for paired and unpaired data, respectively, were used for analysis with a P < 0.05 being considered statistically significant.

RESULTS

Mean scores (% correct response) +/- SD were as follows (*P < 0.05 vs Group I). [table: see text] For the swine model, the best scores were with pericardial fluid (25.0% pre vs 69.4% post in Group I) and the worst scores were with RUQ fluid (5.6% pre vs 22.2% post in Group I). Postworkshop dynamic video scores were always higher than the swine model scores in Group I (100% correct video scores for pericardial fluid).

CONCLUSIONS

This study confirms the trauma ultrasound workshop teaching effectiveness. For testing, the swine model (especially RUQ) was more difficult. In postcourse evaluation, the dynamic human video was considered more relevant, realistic, and less costly for repeated testing of the residents.

Rapid detection of traumatic effusion using surgeon-performed ultrasonography

BACKGROUND

In the injured patient, rapid assessment of the thorax can yield critical information for patient management and triage.

OBJECTIVES

The objectives of this prospective study were (1) to determine if experienced surgeon sonographers could successfully use a focused thoracic ultrasonographic examination to detect traumatic effusion, and (2) to compare the accuracy and efficiency of ultrasonography with supine portable chest radiography.

METHODS

Surgeon-sonographers performed thoracic ultrasonographic examinations on patients with blunt and penetrating torso injuries during the Advanced Trauma Life Support secondary survey. All patients also underwent portable chest radiography. Performance times for ultrasonography and chest radiography were recorded. Comparisons were made of the performance times and accuracy of both tests in detecting traumatic effusion.

RESULTS

In 360 patients, there were 40 effusions, 39 of which were detected by ultrasonography and 37 of which were detected by chest radiography. The 97.5% sensitivity and 99.7% specificity observed for thoracic ultrasonography were similar to the 92.5% sensitivity and 99.7% specificity for portable chest radiography. Performance time for ultrasonography was significantly faster than that for chest radiography (1.30 +/- 0.08 vs. 14.18 +/- 0.91 minutes, p < 0.0001).

CONCLUSION

Surgeons can accurately perform and interpret a focused thoracic ultrasonographic examination to detect traumatic effusion. Surgeon-performed thoracic ultrasonography is as accurate but is significantly faster than supine portable chest radiography for the detection of traumatic effusion.

The emerging role of bedside ultrasonography in trauma care

Ultrasonography has emerged as a primary imaging modality in the evaluation of the trauma victim. Both emergency physicians and surgeons have been proven capable of performing this rapid, noninvasive evaluation of the chest and abdomen. This article describes the trauma ultrasound examination and illustrates how bedside ultrasonography can be incorporated into routine trauma care.

Ultrasonography in blunt abdominal trauma

This article discusses studies of the use of ultrasound in patients with blunt abdominal trauma, both in initial assessment and ongoing evaluation. Reviews of studies of children and adults to detect the presence and extent of hemoperitoneum and organ injuries are presented. Ultrasound results are compared with diagnostic peritoneal lavage, computed tomography, clinical course, and autopsy results. The central question addressed is to what extent can ultrasonography replace or supplement other techniques, particularly diagnostic peritoneal lavage, in the assessment of patients with blunt abdominal trauma. Ultrasound equipment, technique, scoring scales, limitations, and training issues are also addressed.

Abdominal injuries without hemoperitoneum: a potential limitation of focused abdominal sonography for trauma (FAST)

BACKGROUND

Focused abdominal sonography for trauma (FAST) relies on hemoperitoneum to identify patients with injury. Blunt trauma victims (BTVs) with abdominal injury, but without hemoperitoneum, on admission are at risk for missed injury.

METHODS

Clinical, radiologic, and FAST data were collected prospectively on BTVs over a 12-month period. All patients with FAST-negative for hemoperitoneum were further analyzed. Examination findings and associated injuries were evaluated for association with abdominal lesions.

RESULTS

Of 772 BTVs undergoing FAST, 52 (7%) had abdominal injury. Fifteen of 52 (29%) had no hemoperitoneum by admission computed tomographic scan, and all had FAST interpreted as negative. Four patients with splenic injury underwent laparotomy. Six other patients with splenic injury and five patients with hepatic injury were managed nonoperatively. Clinical risk factors significantly associated with abdominal injury in BTVs without hemoperitoneum include: abrasion, contusion, pain, or tenderness in the lower chest or upper abdomen; pulmonary contusion; lower rib fractures; hemo- or pneumothorax; hematuria; pelvic fracture; and thoracolumbar spine fracture.

CONCLUSIONS

Up to 29% of abdominal injuries may be missed if BTVs are evaluated with admission FAST as the sole diagnostic tool. Consideration of examination findings and associated injuries should reduce the risk of missed abdominal injury in BTVs with negative FAST results.

Prospective study investigating routine usage of ultrasonography as the initial diagnostic modality for the evaluation of children sustaining blunt abdominal trauma

In this prospective study, 217 children sustaining blunt abdominal trauma were initially evaluated with ultrasonography (US) and those with any abnormal ultrasonographic findings were further evaluated with computed tomography. Results of ultrasonographic examination were normal in 157 children and showed abnormalities such as free intraperitoneal fluid (FIF), intra-abdominal organ injury, and intrapleural fluid in 60 children. Computed tomographic examination of the 42 children with organ injury, the seven children with minimal FIF of no definite source, and the three children with intrapleural fluid revealed findings consistent with ultrasonographic findings. Computed tomographic examination of the eight children with more than minimal FIF of no definite source detected by US showed the source as liver injury in one and spleen injuries in two patients. The source of FIF could not be identified with computed tomography in five patients. After clinic follow-up examination, one of these five patients was operated on for abdominal tenderness, fever, and air-fluid levels detected on plain abdominal radiographs, and duodenal perforation was encountered. Clinical courses of the patients with normal ultrasonographic findings were uneventful. We conclude that US, aside from being a screening tool, is alone sufficient in the evaluation of the majority of the children sustaining blunt abdominal trauma. Although this is a preliminary study with further work needed to be done, we propose that further evaluation with computed tomography should be performed on those children in whom more than minimal FIF of no definite source is detected with US.

Use of abdominal ultrasonography to assess pediatric splenic trauma. Potential pitfalls in the diagnosis

OBJECTIVE

The purpose of this study was to evaluate the accuracy of abdominal ultrasonography (US) for screening and grading pediatric splenic injury.

SUMMARY BACKGROUND DATA

The use of abdominal US has increased rapidly as a method of evaluating organ damage after blunt abdominal trauma. Despite US's increasing use, little is known about its accuracy in children with splenic injury.

METHODS

Children (N = 32) suffering blunt abdominal trauma who were diagnosed with splenic injury by computerized tomography (CT) scan prospectively were enlisted in this study. Degree of splenic injury was evaluated by both CT and US. The ultrasounds were evaluated by an initial reading as well as by a radiologist who was blinded as to the results of the CT.

RESULTS

Twelve (38%) of the 32 splenic injuries found on CT were missed completely on the initial reading of the US. When the ultrasounds were graded in a blinded fashion, 10 (31%) of the splenic lacerations were missed and 17 (53%) were downgraded. Seven (22%) of the 32 splenic fractures were not associated with any free intraperitoneal fluid on the CT scan.

CONCLUSIONS

This study has shown that US has a low level of sensitivity (62% to 78%) in detecting splenic injury and downgrades the degree of injury in the majority of cases. Reliance on free intraperitoneal fluid may be inaccurate because not all patients with splenic injury have free intra-abdominal fluid. Based on these findings, US may be of limited use in the initial assessment, management, and follow-up of pediatric splenic trauma.

Ultrasound in the evaluation and management of blunt abdominal trauma

Failure to detect intraabdominal injury in the patient with blunt trauma may result in significant morbidity and mortality. The diagnosis of abdominal injury remains a clinical challenge. Presented here is a review of recent literature comparing ultrasound with diagnostic peritoneal lavage and computed tomography in the evaluation of blunt abdominal trauma.

Use of ultrasound to determine need for laparotomy in trauma patients

STUDY OBJECTIVE

To determine whether abdominal ultrasound can be used routinely as the primary screening test to identify the need for laparotomy in trauma patients.

METHODS

Ultrasound was used at a Level II trauma center as a primary screening test for evaluation of intraabdominal injury. We reviewed the charts of all patients from trauma codes presenting between January 1, 1991, and December 31, 1993, to determine the results of abdominal ultrasound evaluation and to learn whether laparotomy was required.

RESULTS

A total of 2,013 trauma patients presented during the study interval. Ultrasound was performed in 1,631 patients as the primary screening test for abdominal injury (mean time after arrival, 22.9 minutes), abdominal computed tomography (CT) was performed as the primary screen on 8 (mean time, 68.6 minutes), and 93 patients underwent both ultrasound and CT of the abdomen. Of 86 patients requiring laparotomy who were screened by ultrasound, 80 had positive diagnostic findings, for a sensitivity of 93.0%. Of the 1,545 ultrasound-screened patients who did not require laparotomy, 1,390 had negative findings, for a specificity of 90.0%. None of the patients with negative ultrasound results died or sustained identifiable mortality as a consequence of their negative scans.

CONCLUSION

Ultrasound is a sensitive and specific test with which to evaluate trauma patients for abdominal injury requiring surgery. Routine abdominal ultrasound can be performed at the bedside in the emergency department as a timely, noninvasive diagnostic test. This use of a screening abdominal ultrasound examination can improve clinical decision-making for the use of emergency laparotomy. Ultrasound may be a better alternative to CT or diagnostic peritoneal lavage for the initial screening evaluation of abdominal trauma.

Emergency department ultrasound services by emergency physicians: model for gaining hospital approval

We anticipate that over the next few years, emergency physician use of emergency department ultrasound will become the standard of care. However, many EDs are hampered in their efforts to gain hospital approval for emergency physician use of ultrasound because of the lack of publicized information regarding the goals of such use, the scope of emergency physician ultrasound privileges, emergency physician ultrasound credentialing criteria, and ED ultrasound quality-improvement plans. In this article we address these issues and provide an example of a proposal used successfully to gain hospital approval for ED use of ultrasound by emergency physicians.

Hypotension after blunt abdominal trauma: the role of emergent abdominal sonography in surgical triage

OBJECTIVE

Trauma victims with hypotension require a rapid and reliable localization of bleeding and expedient surgical triage. Our hypothesis is that emergent abdominal sonography (EAS) is a rapid and accurate test of the need for urgent laparotomy in blunt trauma victims with hypotension.

METHODS

Among 400 blunt trauma victims entered in a prospective blind study of EAS, a subgroup of 69 (17%) patients had a systolic blood pressure < or = 90 mm Hg during their initial assessment. Although the EAS results [(+) = fluid, (-) = no fluid] were not used in clinical decision making, the potential contribution of EAS to patient care was examined.

RESULTS

The mean Injury Severity Score was 32. Twenty-two (32%) patients were EAS (+), of which 19 required an acute laparotomy. No laparotomies were performed in the 47 EAS (-) patients. The EASs required 19 +/- 5 seconds in the EAS (+) group and 154 +/- 13 seconds in the EAS (-) group. Twenty of the 22 positive EASs had free fluid in Morison's pouch. All 13 patients with an ultrasound score > or = 3 had a laparotomy. The primary etiology of hypotension was blood loss in 42 patients, hemoperitoneum in 18, and retroperitoneal hemorrhage in 12.

CONCLUSION

EAS is a rapid and accurate indicator of the need for urgent laparotomy in the hypotensive blunt trauma victim. Further, a negative EAS can hasten the search for other causes of hypotension. Diagnostic peritoneal lavage may become obsolete in centers with EAS capabilities.

Pediatric abdominal surgical emergencies

Pediatric abdominal surgical emergencies may present the primary physician with a diagnostic challenge. A systematic approach will help to minimize missed diagnoses and resultant complications. It always must be kept in mind that children often have atypical presentations of common entities. Prudent and directed use of laboratory and imaging studies will minimize misdiagnosis. The early involvement of surgical consultants in the care of pediatric patients who have significant abdominal symptoms or findings is always appropriate.

Ultrasound training during ATLS: an early start for surgical interns

OBJECTIVES

Determine if: (1) surgical interns could learn essential ultrasound principles of the focused assessment for the sonographic examination of the trauma patient (FAST) during Advanced Trauma Life Support (ATLS), and (2) swine are adequate models for learning the FAST.

DESIGN

Lecture, videotape, pre/posttests, and practical examination.

METHODOLOGY

Day 1: Survey, pretest, lecture, and videotape. Day 2: Three swine, used in ATLS, had diagnostic peritoneal lavage catheters reinserted to infuse fluid and produce "positive" ultrasound examinations. Two fresh swine were "negatives"; however, all five swine were draped similarly to disguise interventions. Interns were tested individually by surgeon-sonographers to determine whether the ultrasound image was "positive" or "negative." Posttests were completed while surgeons performed postmortem examinations on two swine.

STATISTICS

Paired Student's t test and Wilcoxon Rank Sum test.

RESULTS

Survey (5 min): 48% had exposure to ultrasound. Relationship of test scores showed no significant difference (p = 0.46 to 0.91) between interns with and without ultrasound experience. Tests (30 min): Mean pre- and posttests scores = 65.6 and 90.8, respectively (p < 0.001). Practical examination (140 min): Mean score = 89.6. Postmortem examinations: Left hepatic lobe partially obscured the spleen.

CONCLUSIONS

(1) Surgical interns can learn essential ultrasound principles of the FAST during ATLS (2) Swine are feasible models for learning the FAST.

Ultrasound in the diagnosis of injury

Ultrasound is one of several modalities useful in the work-up of an injured patient. It is a bedside technique which is quick, economical and highly reliable in filtering out the patients who are in urgent need of laparotomy. For the moment, this is the prime and only function of this modality. The US examination can and should be repeated with a very low threshold. Apart from the complication rate, which is zero for US, it shares many virtues with DPL. Ultrasonography in a badly injured victim is a challenging investigation which should be done by an expert. In most situations, this will be a radiologist whose presence in the emergency room could further be used for expert film reading and development as well as the unhampered implementation of a rational follow-up imaging strategy. Follow-up modalities, however impressive, should not be compared with first-line investigations. In expert hands, accuracy figures between DPL and US do not differ decisively but one must bear in mind that DPL spans only one compartment while US gives information about much more vital areas. DPL is complementary to US; it is of paramount importance to understand that DPL spoils the US examination (and CT as well) but is not hindered by repeated US. DPL can and should be used to investigate the nature of free intra-peritoneal fluid when the amount does not warrant laparotomy. Neither US nor DPl are substitutes for sound clinical judgement.

Emergent abdominal sonography as a screening test in a new diagnostic algorithm for blunt trauma

Although there is an interest in emergent abdominal sonography (EAS), the clinical utilization of EAS in North America is minimal. The purpose of this study was to develop a new diagnostic algorithm for blunt abdominal injury based on a prospective blinded comparison of EAS, diagnostic peritoneal lavage (DPL), and computed tomography (CT). EAS (+ = fluid, - = no fluid) was performed before the DPL or CT, in 400 patients with a mean Injury Severity Score of 26; 293 had a CT and 107 had a DPL. The EASs required 2.6 +/- 1.2 minutes with 82% < or = 3 minutes. The accuracy of EAS for free fluid was 94% with a positive and negative predictive value of 82 and 96%, respectively. Only 1 of 338 patients with EAS- had an acute therapeutic laparotomy. Three patients with EAS- had a delayed laparotomy based on evolving clinical findings. The radiologists interpretation of the EAS video disagreed with the clinician sonographer in only 3% of cases. Based on these results, a diagnostic algorithm was developed using EAS as a screening test with selective use of DPL and CT. Emergent abdominal sonography performed by clinician sonographers is a rapid and accurate test for peritoneal fluid in blunt trauma victims, and the need for laparotomy in patients with a negative EAS is rare. Our study supports the routine use of EAS as a screening test in a diagnostic algorithm for the evaluation of blunt abdominal trauma.

Blunt abdominal trauma

Assessment and management of patients with blunt abdominal trauma remains a challenge for emergency physicians. The spectrum of injury ranges from the trivial to the catastrophic and the initial assessment, resuscitation, and investigation of patients with abdominal trauma must be individualized. This article covers the important aspects of patient history and physical examination and addresses the relevant investigative tools available. An approach to the assessment of patients with abdominal trauma is provided; the goal is to diagnose significant injuries as soon as possible and avoid the pitfall of a delayed or missed diagnosis.