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

The value of indicated computed tomography scan of the chest and abdomen in addition to the conventional radiologic work-up for blunt trauma patients

BACKGROUND

Multidetector computed tomography (CT) is more sensitive and specific in detecting traumatic injuries than conventional radiology is. However, still little is known about the diagnostic value and the therapeutic impact of indicated thoraco-abdominal CT scan when it is performed in addition to the complete conventional radiologic work-up for blunt trauma patients.

METHODS

Clinical and radiologic data from 106 consecutive blunt trauma patients were reviewed. Diagnoses revealed by conventional work-up of the chest, abdomen, pelvis, and thoracolumbar spine were compared with that detected by CT scan of the chest and abdomen. Unexpected findings by CT scan and rejected diagnoses by CT scan were collected. Therapeutic consequences of these diagnoses were determined both theoretically and collected from the medical records.

RESULTS

In 74% (95% confidence interval [CI] 65-82) of the 106 patients, 1 or more diagnoses were demonstrated by chest or abdominal CT scan, whereas they had not been revealed by preceding conventional work-up. This resulted in an actual change of treatment in 34% (95% CI 25-43) of the patients. CT scan of the chest resulted in a change of treatment in 33% (95% CI 23-44) and abdominal CT scan in 16% (95% CI 9-24).

CONCLUSIONS

CT scan of the chest and abdomen has a high diagnostic value in the evaluation of blunt trauma patients, when it is selectively performed in addition to the early conventional radiologic work-up. Unexpected pathologic findings are detected by CT scan in the majority of the patients. These findings result in an adaptation of treatment in a substantial number of the patients.

Blunt abdominal trauma: diagnostic performance of contrast-enhanced US in children--initial experience

PURPOSE

To prospectively compare the sensitivity and specificity of ultrasonography (US) with those of contrast material-enhanced US in the depiction of solid organ injuries in children with blunt abdominal trauma, with contrast-enhanced computed tomography (CT) as the reference standard.

MATERIALS AND METHODS

The study protocol was approved by the ethics board, and written informed consent was obtained from parents. US, contrast-enhanced US, and contrast-enhanced CT were performed in 27 consecutive children (19 boys, eight girls; mean age, 8.9 years +/- 2.8 [standard deviation]) with blunt abdominal trauma to determine if solid abdominal organ injuries were present. Sensitivity, specificity, agreement, accuracy, number of lesions correctly identified, and positive and negative predictive values were determined for US and contrast-enhanced US, as compared with contrast-enhanced CT.

RESULTS

In 15 patients, contrast-enhanced CT findings were negative. Contrast-enhanced CT depicted 14 solid organ injuries in 12 patients. Lesions were in the spleen (n = 7), liver (n = 4), right kidney (n = 1), right adrenal gland (n = 1), and pancreas (n = 1). Contrast-enhanced US depicted 13 of the 14 lesions in 12 patients with positive contrast-enhanced CT findings and no lesions in the patients with negative contrast-enhanced CT findings. Unenhanced US depicted free fluid in two of 15 patients with negative contrast-enhanced CT findings and free fluid, parenchymal lesions, or both in eight of 12 patients with positive contrast-enhanced CT findings. Overall, the diagnostic performance of contrast-enhanced US was better than that of US, as sensitivity, specificity, and positive and negative predictive values were 92.2%, 100%, 100%, and 93.8%, respectively.

CONCLUSION

Contrast-enhanced US was almost as accurate as contrast-enhanced CT in depicting solid organ injuries in children.

Performance of abdominal ultrasonography in pediatric blunt trauma patients: a meta-analysis

OBJECTIVE

The objective of the study was to obtain the best estimates of the test performance of abdominal ultrasonography (US) for identifying children with intraabdominal injuries (IAIs).

METHODS

We gathered studies on the use of abdominal US in injured children from the following sources: a MEDLINE and Embase search, hand searches of 5 specialty journals and 4 clinical textbooks, the bibliographies of all identified articles, and contact with experts. Both prospective and retrospective studies were included if they used abdominal US for the detection of intraperitoneal fluid or IAIs in blunt trauma patients less than 18 years of age. All authors independently abstracted data from the selected studies. Disagreements between abstractors were resolved by mutual agreement.

RESULTS

Twenty-five articles met the inclusion criteria, and 3838 children evaluated with abdominal US were included. Abdominal US had the following test characteristics for identifying children with hemoperitoneum: sensitivity, 80% (95% confidence interval [CI] 76%-84%); specificity, 96% (95% CI 95%-97%); positive likelihood ratio, 22.9 (95% CI 17.2-30.5); and negative likelihood ratio, 0.2 (95% CI 0.16-0.25). Using the most methodologically rigorous studies, however, yielded the following test characteristics of abdominal US for identifying children with hemoperitoneum: sensitivity, 66% (95% CI 56%-75%); specificity, 95% (95% CI 93%-97%); positive likelihood ratio, 14.5 (95% CI 9.5-22.1); and negative likelihood ratio, 0.36 (95% CI 0.27-0.47).

CONCLUSIONS

Abdominal US has a modest sensitivity for the detection of children with hemoperitoneum; however, its test performance characteristics worsen when only the most methodologically rigorous articles are included. A negative US examination has questionable utility as the sole diagnostic test to rule out the presence of IAI. Because of the high risk of IAI, a hemodynamically stable child with a positive US examination should immediately undergo abdominal computed tomographic scanning.

The utility of focused assessment with sonography for trauma as a triage tool in multiple-casualty incidents during the second Lebanon war

OBJECTIVE

The purpose of this study was to evaluate the role of focused assessment with sonography for trauma (FAST) as a triage tool in multiple-casualty incidents (MCIs) for a single international conflict.

METHODS

The charts of 849 casualties that arrived at our level 1 trauma referral center were reviewed. Casualties were initially triaged according to the Injury Severity Score at the emergency department gate. Two-hundred eighty-one physically injured patients, 215 soldiers (76.5%) and 66 civilians (23.5%), were admitted. Focused assessment with sonography for trauma was performed in 102 casualties suspected to have an abdominal injury. Sixty-eight underwent computed tomography (CT); 12 underwent laparotomy; and 28 were kept under clinical observation alone. We compared FAST results against CT, laparotomy, and clinical observation records.

RESULTS

Focused assessment with sonography for trauma results were positive in 17 casualties and negative in 85. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of FAST were 75%, 97.6%, 88.2%, 94.1%, and 93.1%, respectively. A strong correlation between FAST and CT results, laparotomy, and clinical observation was obtained (P < .05).

CONCLUSIONS

In a setting of a war conflict-related MCI, FAST enabled immediate triage of casualties to laparotomy, CT, or clinical observation. Because of its moderate sensitivity, a negative FAST result with strong clinical suspicion demands further evaluation, especially in an MCI.

The value of contrast-enhanced gray-scale ultrasound in the diagnosis of hepatic trauma: an animal experiment

BACKGROUND

Conventional ultrasonography (US) shows markedly lower sensitivity in detecting parenchymal injury and active bleeding in abdominal organs. This study was designed to evaluate the utility of contrast-enhanced US (CEUS) in the diagnosis of blunt trauma and active hemorrhage of the liver in an animal model.

METHODS

Sixteen blunt injuries and 40 lacerations with active hemorrhage were created in livers of 14 pigs using laparotomy. The lacerations were divided into two groups: group I, in which the velocity of the traumatized artery was >20 cm/s; and group II, in which the velocity of the traumatized artery was < or =20 cm/s. Twenty minutes after the blunt trauma and immediately after the laceration was created, conventional US and CEUS were performed to observe the sonographic characteristics of trauma.

RESULTS

The sensitivity of CEUS in detecting blunt hepatic trauma (100%; 16 of 16) was significantly higher than that of conventional US (37.5%; 6 of 16) (p < 0.001) based on the histopathology gold standard. Active hemorrhage was clearly detected as hyperechoic enhanced linear or clumpy regions in all of the lacerations in group I (100%; 20 of 20) and in 65% (13 of 20) of the lacerations in group II on CEUS. Acoustic shadowing was observed posterior to the enhanced hemorrhagic site in 12 lacerations from group I and in five lacerations from group II.

CONCLUSION

In this animal model, CEUS was found to be useful in detecting blunt trauma and active hemorrhage in the liver, which might significantly improve the efficacy of US for the diagnosis of hepatic trauma.

Clinician-performed focused sonography for the resuscitation of trauma

Traumatic death remains pandemic. The majority of preventable deaths occur early and are due to injuries or physiologic derangements in the airway, thoracoabdominal cavities, or brain. Ultrasound is a noninvasive and portable imaging modality that spans a spectrum between the physical examination and diagnostic imaging. It allows trained examiners to immediately confirm important syndromes and answer clinical questions. Newer technologies greatly increase the fidelity, accessibility, ease of use, and informatic manipulation of the results. The early bedside use of focused ultrasound as the initial imaging modality used to detect hemoperitoneum and hemopericardium in the resuscitation of the injured patient has become an accepted standard of care. Widespread dissemination of basic ultrasound skills and technology to facilitate this brings ultrasound to many resuscitative and critical care areas. Although not as widely appreciated, the focused use of ultrasound may also have a role in detecting hemothoraces and pneumothoraces, guiding airway management, and detecting increased intracranial pressure. Intensivists generally utilize a treating philosophy that requires the real-time integration of many divergent sources of information regarding their patients' anatomy and physiology. They are therefore positioned to take advantage of focused resuscitative ultrasound, which offers immediate diagnostic information in the early care of the critically injured.

Multidetector-Row Computed Tomography Imaging of Splenic Trauma

The spleen is the intra-abdominal organ most often injured as a result of blunt trauma. Multidetector-row computed tomography (MDCT) plays an important role in the detection and characterization of splenic injury. It has been shown to be highly accurate and can detect splenic vascular lesions, the presence of which has been shown to be a predictor of failure of nonoperative management. The increased use of angiography and splenic artery embolization in the management of such injuries has led to improved success rates with nonoperative management. This article reviews the various appearances of the injured spleen and discusses the use of MDCT in the initial evaluation of injury. The indications for angiography and embolization are reviewed, with examples of appearances of the postembolization spleen.

Appearance of Solid Organ Injury with Contrast-Enhanced Sonography in Blunt Abdominal Trauma: Preliminary Experience

OBJECTIVE

The purpose of this study was to compare the detection rate of injury and characterize imaging findings of contrast-enhanced sonography and non-contrast-enhanced sonography in the setting of confirmed solid organ injury.

SUBJECTS AND METHODS

This prospective study involved identifying hepatic, splenic, and renal injuries on contrast-enhanced CT. After injury identification, both non-contrast-enhanced sonography and contrast-enhanced sonography were performed to identify the possible injury and to analyze the appearance of the injury. The sonographic appearance of hepatic, splenic, and renal injuries was then analyzed, and the conspicuity of the injuries was graded on a scale from 0 (nonvisualization) to 3 (high visualization).

RESULTS

Non-contrast-enhanced sonography revealed 11 (50%) of 22 injuries, whereas contrast-enhanced sonography depicted 20 (91%) of 22 injuries. The average grade for conspicuity of injuries was increased from 0.67 to 2.33 for spleen injuries and from 1.0 to 2.2 for liver injuries comparing non-contrast-enhanced with contrast-enhanced sonography, respectively, on a scale from 0, being nonvisualization, to 3, being high visualization. The splenic injuries appeared hypoechoic with occasional areas of normal enhancing splenic tissue within the laceration with contrast-enhanced sonography. Different patterns were observed in liver injuries including a central hypoechoic region. In some liver injuries there was a surrounding hyperechoic region.

CONCLUSION

Contrast-enhanced sonography greatly enhances visualization of liver and spleen injuries compared with non-contrast-enhanced sonography. Solid organ injuries usually appeared hypoechoic on contrast-enhanced sonography, but often a hyperechoic region surrounding the injury also was identified with liver injuries.

Diagnostic peritoneal aspiration--the foster child of DPL: a prospective observational study

BACKGROUND

The abdomen is routinely considered as a possible source of bleeding in hypotensive and unevaluable blunt multitrauma patients. These patients are often unstable to be transported for abdominal computed tomography (CT). Emerging data on Focused Assessment with Sonography for Trauma (FAST) exam questions its initially reported high accuracy. We hypothesized that Diagnostic Peritoneal Aspiration (DPA), without a full lavage, accurately detects intraperitoneal blood if present in sufficient volume to cause hypotension and warrant emergent operation.

METHODS

Over 24 months (July 2002-June 2004), 62 severe blunt trauma patients (Injury Severity Score: 32+/-17) with admission systolic blood pressure equal to or less than 90 mmHg were enrolled prospectively. Percutaneous DPA was performed after FAST. Aspiration of any quantity of blood was considered a positive test. Sensitivity and specificity of DPA and FAST were calculated against findings from abdominal CT, laparotomy, or autopsy.

RESULTS

Twenty-two patients (35%) required emergent laparotomy and 39 (63%) died. DPA was performed in less than 1 min with no complications. Sensitivity and specificity of DPA was 89% and 100%, respectively, whereas for FAST it was 50% and 95%. Two (3%) false negative DPA were recorded; one patient had a minor liver laceration with 250 ml of free blood and the other a leaking retroperitoneal pelvic hematoma in the presence of cirrhosis with 600 ml of bloody ascitic fluid. There were no false positive DPA. Nine (14.5%) false negative and two (3%) false positive FAST were recorded in patients who were found to have at laparotomy 1575+/-1070 ml of hemoperitoneum on average.

CONCLUSIONS

Percutaneous DPA is accurate, rapid, safe, and superior to FAST for the diagnosis of abdominal blood as the source of hemodynamic instability, requiring emergent surgery, in blunt multitrauma patients.

Blunt abdominal trauma: emergency contrast-enhanced sonography for detection of solid organ injuries

OBJECTIVE

The objective of our study was to prospectively compare the diagnostic value of sonography and contrast-enhanced sonography with CT for the detection of solid organ injuries in blunt abdominal trauma patients.

SUBJECTS AND METHODS

Sonography, contrast-enhanced sonography, and CT were performed to assess possible abdominal organ injuries in 69 nonconsecutive hemodynamically stable patients with blunt abdominal trauma and a strong clinical suspicion of abdominal lesions. Sonography and contrast-enhanced sonography findings were compared with CT findings, the reference standard technique.

RESULTS

Thirty-two patients had 35 abdominal injuries on CT (10 kidney or adrenal lesions, seven liver lesions, 17 spleen lesions, and one retroperitoneal hematoma). Sixteen lesions were detected on sonography, and 32 were seen on contrast-enhanced sonography. The sensitivity and specificity of sonography were 45.7% and 91.8%, respectively, and the positive and negative predictive values were 84.2% and 64.1%, respectively. Contrast-enhanced sonography had a sensitivity of 91.4%, a specificity of 100%, and positive and negative predictive values of 100% and 92.5%, respectively.

CONCLUSION

Contrast-enhanced sonography was found to be more sensitive than sonography and almost as sensitive as CT in the detection of traumatic abdominal solid organ injuries. It can therefore be proposed as a useful tool in the assessment of blunt abdominal trauma.

Color power Doppler US and contrast-enhanced US features of abdominal solid organ injuries

Utilization of color power Doppler and sonographic contrast agents to basic ultrasound (US) further improve the detection and characterization of abdominal injuries, increasing the diagnostic accuracy and value of US as an important technique in the evaluation of the abdominal trauma. This paper provides an illustrated summary of our clinical experience with color power Doppler US (CD-US) and contrast-enhanced US (CE-US) in the evaluation of abdominal solid organ injuries, involving 32 documented cases over a 2-year period. The findings of the CD-US and CE-US were compared with those provided by state-of-the-art contrast-enhanced multidetector 16-row CT.

What Does Ultrasonography Miss in Blunt Trauma Patients With A Low Glasgow Coma Score (GCS)?

BACKGROUND

The role of ultrasound (US) as a screening tool for the evaluation of blunt abdominal trauma is still controversial. Determining the types of missed injuries and the accuracy of US in patients with a low GCS will improve the evaluation of these blunt trauma patients.

METHODS

Prospectively collected data from the trauma registry of a Level I trauma center was reviewed.

RESULTS

7,952 patients were included in the study. US examination had an accuracy of 89%, sensitivity of 77%, specificity of 97%, positive predictive value (PPV) of 78%, and negative predictive value (NPV) of 98%. GCS correlated with ISS and base deficit levels. US examination had a significantly lower accuracy in patients with a low GCS and in women.

CONCLUSION

The sensitivity and specificity of US examination is similar in those with normal and low GCS. Therefore ultrasonographic examination may be considered a good screening tool for the evaluation of patients with blunt abdominal trauma, but its accuracy is diminished in patients with a low GCS. Further imaging may be warranted in these patients.

Prospective Study to Evaluate the Influence of FAST on Trauma Patient Management

BACKGROUND

Previous studies have concentrated on the accuracy of Focused Assessment with Sonography in Trauma (FAST), but evaluation of whether FAST changes subsequent management has not been fully assessed.

METHODS

This prospective study compared 419 trauma admissions in two groups, FAST and no-FAST, for demographics, time of resuscitation, and action after resuscitation. The 194 patients undergoing FAST had their management plan specified before, and confirmed after, FAST was performed to assess for change in management. To ensure scan consistency and to minimize bias, criteria were established to define an adequate FAST.

RESULTS

FAST was performed in 194 patients (46%), assessing for free fluid. Management was changed in 59 cases (32.8%) after FAST. Laparotomy was prevented in 1 patient, computed tomography was prevented in 23 patients, and diagnostic peritoneal lavage was prevented in 15 patients. Computed tomography rates were reduced from 47% to 34% and diagnostic peritoneal lavage rates were reduced from 9% to 1%.

CONCLUSIONS

FAST plays a key role in trauma, changing subsequent management in an appreciable number of patients.

Usefulness of Multidetector Computed Tomography for the Initial Assessment of Blunt Abdominal Trauma Patients

BACKGROUND

The prompt detection and accurate localization of abdominal injuries are difficult. Some diagnostic modalities, including laboratory tests, ultrasound, and diagnostic peritoneal lavage (DPL) were used to evaluate patients with blunt abdominal trauma, with various advantages and pitfalls. We aimed to evaluate the risk and benefit of using multidetector computed tomography (MDCT) as an initial assessment tool for proper diagnosis and treatment planning of patients with blunt abdominal trauma.

METHODS

Two hundred fifty-two patients with blunt abdominal trauma were prospectively enrolled. Multidetector computed tomography was performed during resuscitation. The risk and benefit of using MDCT in the diagnosis and planning of treatment were analyzed.

RESULTS

The time required for a MDCT examination averaged 10.2 minutes. Of the studies done, 224 revealed abdominal injuries. Of those, 34 were performed in patients with unstable hemodynamic status without adverse effect. Prompt diagnosis and proper treatment were given according to the MDCT findings. A total of 43 (17.1%) MDCTs showed contrast extravasation. Active bleeding was confirmed in all and treated with transarterial embolization (30) or surgery (13). Another 58 patients sustained bowel, mesenteric, or pancreatic injuries (BMPI) necessitating laparotomy. The sensitivity, specificity, and accuracy of MDCT in identifying patients with active bleeding or BMPI were all 100%.

CONCLUSIONS

Multidetector computed tomography was useful as a second line initial assessment tool to identify injuries and determine treatment planning in blunt abdominal trauma patients. No increased risk was found if the facility is readily available, the protocol is well designed, and the patient is well prepared.

Moderne Diagnostik des Bauchtraumas

In case of suspected intra-abdominal injury, fast transport of the patient to a suitable hospital is of high priority. The initial clinical examination aims at identifying patients with potentially life-threatening bleeding that require emergency surgery. In patients with penetrating trauma, laparoscopy is favoured to exclude suspected perforation of the peritoneum. If a peritoneal perforation is identified, exploratory laparotomy is recommended to exclude or treat lacerations of the hollow viscus. Although clinical examination should be performed its sensitivity and specificity of up to 82% and 45%, respectively, are not sufficient as the sole screening method. For the further diagnostic workup, diagnostic peritoneal lavage has been completely replaced by abdominal ultrasound examination in Germany and many other countries. Focussing not only on the detection of free abdominal fluid but also searching for parenchymal organ lesions and performing repeated examinations increases accuracy up to 96%, with specificity of 99.8% and sensitivity of 72.1%. Computed abdominal tomography with a helical scanner with and without intravenous contrast media is currently the gold standard of imaging techniques to identify traumatic abdominal injuries. A sensitivity of 97.2% and specificity of 94.7% can be achieved. False negative findings must be expected with hollow organ injuries. Serial clinical and ultrasound examinations as well as lab testing in conjunction with repeated CT may help to identify such lesions. Increased intra-abdominal pressure (IAP) with consecutive abdominal compartment syndrome and multiple organ dysfunction is a delayed complication from conditions such as severe intra-abdominal bleeding, major bleeding from pelvic ring fractures, and profuse fluid resuscitation. The IAP should be measured routinely in patients at risk, and decompression laparotomy may be indicated with pressures of higher than 20 mmHg.

Is definitive abdominal evaluation required in blunt trauma victims undergoing urgent extra-abdominal surgery?

OBJECTIVES

To evaluate the utility of routine abdominal computed tomographic (CT) scanning for abdominal evaluation of blunt trauma patients before urgent extra-abdominal surgery.

METHODS

In this observational cohort study, we prospectively enrolled all blunt trauma patients at least 8 years of age presenting to the emergency department of a Level 1 trauma center who were initially considered to require urgent extra-abdominal surgery within 24 hours of presentation. Patients were excluded if they had any of the following: 1) isolated extremity trauma, 2) signs or symptoms of intra-abdominal injury (including systolic blood pressure < 90 mm Hg; abdominal, flank, or costal margin tenderness; abdominal wall contusion or abrasion; pelvic fracture; and gross hematuria), or 3) unreliable findings on abdominal examination (Glasgow Coma Scale score < 14, paralysis, or mental retardation). Clinical data were documented on a data sheet before abdominal CT scanning.

RESULTS

A total of 254 patients, with a mean (+/-SD) age of 32.3 (+/-16.1) years, were enrolled. A total of 201 patients ultimately underwent urgent extra-abdominal surgery for the following procedures: orthopedic, 182 (91%); facial, 17 (8%); laceration, 7 (3%); vascular, 6 (2%); neurosurgical, 3 (1%); urology, 2 (1%); and ophthalmology, 1 (0.4%). Three patients (1.2%; 95% confidence interval = 0.2% to 3.4%) were found to have intra-abdominal injuries. Two patients had splenic injuries that required only observation. One patient (0.4%; 95% confidence interval = 0% to 2.2%) underwent laparotomy. This patient sustained multiple injuries in a motorcycle crash, including splenic, kidney, and pancreatic injuries, and underwent a splenectomy.

CONCLUSIONS

Abdominal CT scanning has a low yield in trauma patients whose sole indication for diagnostic abdominal evaluation is the need for general anesthesia for urgent extra-abdominal surgery. A small percentage of these patients, however, will have important intra-abdominal injuries such that further refinement of the recommendations for diagnostic study in this select population is needed.

Association between compliance with methodological standards of diagnostic research and reported test accuracy: meta-analysis of focused assessment of US for trauma

PURPOSE

To study whether compliance with methodological standards affected the reported accuracy of screening ultrasonography (US) for trauma.

MATERIALS AND METHODS

Meta-analysis was conducted of prospective investigations in which US was compared with any diagnostic reference test in patients with suspected abdominal injury. Reports were retrieved from electronic databases without language restrictions; added information was gained with manual search. Two reviewers independently assessed methodological rigor by using 27 items contained in the Standards for Reporting of Diagnostic Accuracy (STARD) checklist and the Quality Assessment of Studies of Diagnostic Accuracy included in Systematic Reviews (QUADAS) instrument. Inconsistencies were resolved by means of consensus. Summary receiver operating characteristics and random-effects meta-regression were used to model the effect of methodological standards and other study features on US accuracy.

RESULTS

A total of 62 trials, which included a total of 18,167 participants, were eligible for meta-analysis. The average proportion of men or boys was 71.7%, the mean age was 30.6 years +/- 10.8 (standard deviation), and the mean injury severity score was 16.7 +/- 8.3. The prevalence of abdominal trauma was 25.1% (95% confidence interval [CI]: 21.1%, 29.1%). Pooled overall sensitivity and specificity of US were 78.9% (95% CI: 74.9%, 82.9%) and 99.2% (95% CI: 99.0%, 99.4%), respectively. Varying end points (hemoperitoneum or organ damage) did not change these results. US accuracy was much lower in children (sensitivity, 57.9%; specificity, 94.3%). Strong heterogeneity was observed in sensitivity, whereas specificity remained constant across trials. There was evidence of publication bias. Initial interobserver agreement with methodological standards ranged from poor (kappa = 0.03, independent verification of US findings) to perfect (kappa = 1.00, sufficiently short interval between US and reference test). By consensus, studies fulfilled a median of 13 methodological criteria (range, five to 20 criteria). In investigations that lacked individual methodological standards, researchers overestimated pooled sensitivity, with predicted differences of 9%-18%. The use of a single reference test, specification of the number of excluded patients, and calculation of CIs independently contributed to predicted sensitivity in a multivariate model. In 16 investigations (1309 subjects), a single reference test was used, which provided a combined sensitivity of 66.0% (95% CI: 56.2%, 75.8%).

CONCLUSION

Bias-adjusted sensitivity of screening US for trauma is low. Adherence to methodological standards included in appraisal instruments like STARD and QUADAS is crucial to obtain valid estimates of test accuracy.

Ultrasound detection of blunt urological trauma: a 6-year study

The objective of this study was to assess the utility of emergency ultrasonography in the detection of blunt urological injury. A retrospective review was conducted of all consecutive emergency blunt trauma ultrasonograms (US) obtained at a level I trauma centre from January 1995 to January 2001. Among the 4320 emergency ultrasonograms performed, 596 patients (14%) had intraabdominal injury and, of these, 99 patients (17%) had urological injuries. The sensitivity of ultrasound for all urological injuries was 67%, and specificity was 99.8%. For isolated urological injuries, sensitivity and specificity were 55.6 and 99.8%, respectively. Ultrasound was most accurate in the detection of grade III renal injuries, identifying 14/15 (93%), and 13 underwent laparotomy. For isolated urological injuries, 15 of 25 (60%) patients with a true-positive US underwent laparotomy compared to 3 of 20 (15%) with a false-negative US. Isolated urological injury was significantly associated with an ultrasonographic pattern of free fluid in the left upper quadrant and the left pericolic gutter (odds ratio=55.1; P<0.001), followed by isolated fluid in the left pericolic gutter (odds ratio=8.6; P=0.04). Although emergency ultrasonography is useful in the triage of patients with blunt urological trauma, it may miss significant urological injury requiring further intervention. As most renal injuries may be managed non-operatively, further studies such as contrast-enhanced CT or angiography should be obtained in the stable patient with suspected blunt urological injury.

Hypotensive Patients with Blunt Abdominal Trauma: Performance of Screening US

PURPOSE

To determine retrospectively the accuracy of screening ultrasonography (US) in patients with hypotension (systolic blood pressure <or= 90 mm Hg) after blunt abdominal trauma.

MATERIALS AND METHODS

The investigational review board approved the study and waived informed consent. The study group consisted of 128 hypotensive patients with blunt abdominal trauma who underwent screening US over a 9-year period. Abdomens were scanned for free fluid and for parenchymal heterogeneity in visceral organs; scans that depicted these were considered positive. Prospective reports were used to calculate diagnostic performance. Patients were retrospectively given a fluid score according to the number of fluid pockets visualized (0, 1, or > or =2) (consensus by three readers) and were assigned to a low- or high-risk group according to the presence of hematuria and/or axial fracture on radiographs. Screening US results were compared with findings with the best available reference standard (computed tomography [CT]), repeat US, other diagnostic test, laparotomy, autopsy, clinical course). Data were compared by using chi(2) or Fisher exact test, depending on expected frequencies, with Bonferroni correction for multiple comparisons. Continuous variables were compared by using unpaired Student t test or Mann-Whitney U test, depending on data distribution.

RESULTS

The study included 77 male and 51 female patients (mean age, 42 years). Sensitivity was 85% (44 of 52) for detection of any injuries, 97% (30 of 31) for surgical injuries (ie, injuries requiring surgery), and 100% (10 of 10) for fatal injuries. Specificity was 96% (73 of 76), 82% (80 of 97), and 69% (81 of 118), and accuracy was 91% (117 of 128), 86% (110 of 128), and 71% (91 of 128), for respective injury categories. One nonfatal surgical injury was missed in a high-risk patient. For each injury category, frequency of injury in patients with a fluid score of 2 or more was nine times that in patients with a score of 0 (P < .001 for all comparisons). Frequency of false-negative US findings in high-risk patients was eight times that in low-risk patients (P < .01).

CONCLUSION

In patients who are hypotensive after blunt abdominal trauma and not hemodynamically stable enough to undergo diagnostic CT, negative US findings virtually exclude surgical injury, while positive US findings indicate surgical injury in 64% of cases.

Sonography as the primary screening method in evaluating blunt abdominal trauma

PURPOSE

The radiological evaluation of patients with blunt abdominal trauma can be done with either ultrasound (US) or computed tomography (CT) with strategies varying considerably among institutions. We evaluated the efficacy of our current strategy in which US is used at our hospital as the primary screening tool for patients with blunt abdominal trauma.

METHODS

We retrospectively analysed all patients admitted to our hospital with possible blunt abdominal trauma who underwent abdominal US, abdominal CT and/or a laparotomy during the initial trauma assessment from 1998 until 2002 (n = 1149).

RESULTS

Nine-hundred sixty-one of the 1149 patients had a negative US, of which 922 were true negative, resulting in a negative predictive value of 96%. A CT of the abdomen was performed in 7%. In 1.7% there was delayed diagnosis with no significant additional morbidity. Fourteen of the 103 laparotomies (14%) were non-therapeutic; in 5 of these cases the patients underwent non-therapeutic laparotomy despite the performance of a CT. Seven were emergency operations.

CONCLUSIONS

In our practice, the use of US for the evaluation of acute blunt abdominal trauma is adequate, with a high negative predictive value, a small number of delayed diagnoses, and an acceptable rate of non-therapeutic laparotomies.

Blunt hepatic trauma: evaluation with contrast-enhanced sonography: sonographic findings and clinical application

OBJECTIVE

The purpose of this study was to report our initial experience in the assessment of liver trauma with real-time contrast-enhanced sonography (CES).

METHODS

From January 2000 to December 2003, there were 431 hemodynamically stable patients evaluated with sonography for blunt abdominal trauma. Among these patients, 87 were selected to undergo second-level imaging, consisting of CES and computed tomographic (CT) evaluation. Indications for further assessment were baseline sonographic findings positive for liver injury, baseline sonographic findings positive for injury to other abdominal parenchyma, baseline sonographic findings positive for free fluid only, baseline sonographic findings indeterminate, and baseline sonographic findings negative with persistent clinical or laboratory suspicion.

RESULTS

There were 23 hepatic lesions shown by CT in 21 patients. Peritoneal or retroperitoneal fluid was identified in 19 of 21 positive cases by all 3 imaging modalities. Liver injury was found in 15 patients on sonography and in 19 on CES. Contrast-enhanced sonography compared better than unenhanced sonography with the criterion standard for related injury conspicuity, injury size, completeness of injury extension, and involvement of the liver capsule. Both CES and CT showed intrahepatic contrast material pooling in 2 cases. All patients with false-negative sonographic or CES findings recovered uneventfully.

CONCLUSIONS

Contrast-enhanced sonography is an effective tool in the evaluation of blunt hepatic trauma, being more sensitive than baseline sonography and correlating better than baseline sonography with CT findings. In institutions where sonography is regarded as the initial procedure to screen patients with trauma, this technique may increase its effectiveness. In addition, CES may be valuable in the follow-up of patients with conservatively treated liver trauma.

[Shock trauma room diagnosis: initial diagnosis after blunt abdominal trauma. A review of the literature]

OBJECTIVE

Blunt abdominal trauma is most common in the polytraumatized patient and beside neurocranial trauma one major determinant of early death in these patients. Therefore, immediate recognition of an abdominal injury is of life-saving importance.

METHODS

Clinical trials were systematically collected (Medline, Cochrane and hand searches) and classified into evidence levels (1 to 5 according to the Oxford system).

RESULTS

Clinical examination is not reliable for evaluation of abdominal injury. Abdominal ultrasound, especially if only focusing on free fluid (FAST) is not sensitive enough. Today, CT-scan of the abdomen is the gold-standard in diagnosing abdominal injury. Diagnostic Peritoneal Lavage (DPL) has a high sensitivity but in our region only is used in exceptional cases. The patient with continuing hemodynamical instability after abdominal trauma and evidence of free intraperitonial fluid has to undergo laparotomy.

CONCLUSION

After blunt abdominal trauma, initially ultrasound investigation should be performed in the emergency room. This should not only focus on free intraabdominal fluid but also on organ lesions. Regardless of the findings from ultrasound or clinical examination, the hemodynamically stable patient should undergo a CT-scan of the abdomen in order to proof or exclude an abdominal injury.

Reevaluation of ultrasonography for solid-organ injury in blunt abdominal trauma

OBJECTIVE

To reevaluate the usefulness of ultrasonography for detecting and classifying solid-organ injuries from blunt abdominal trauma by comparing ultrasonography with computed tomography (CT) and laparotomy.

METHODS

Six hundred four patients with blunt abdominal trauma were examined by both B-mode ultrasonography and CT for a study period of 14 years. The ultrasonographic examiners were divided into 2 groups depending on their experience with ultrasonography. The ultrasonographic results were then compared with CT and surgical findings. This was a retrospective study.

RESULTS

In 198 patients, solid-organ injuries were identified on CT, laparotomy, or both. Sensitivity values in group A (experts) were 87.5% for hepatic injuries, 85.4% for splenic injuries, 77.6% for renal injuries, and 44.4% for pancreatic injuries. Sensitivity values in group B were 46.2% for hepatic injuries, 50.0% for splenic injuries, and 44.1% for renal injuries. The detection rates in group A were 80% to 100% for different types of hepatic injuries except superficial injuries (20%) and 70% to 100% for different types of splenic injuries. The detection rates for renal parenchymal and pancreatic duct injuries were 53.3% and 80%, respectively. The detection rates for injuries requiring intervention were 86.1% in group A and 66.7% in group B.

CONCLUSIONS

The sensitivity of ultrasonography with the use of CT and surgical findings as reference standards decreased compared with our prior study. However, ultrasonography was found to enable experienced examiners to detect and classify parenchymal injuries efficiently, despite disadvantages in detecting superficial and vascular injuries. Ultrasonography should be used to explore not only free fluid but also solid-organ injuries.

Secondary ultrasound examination increases the sensitivity of the FAST exam in blunt trauma

INTRODUCTION

Approximately one third of stable patients with significant intra-abdominal injury do not have significant intraperitoneal blood evident on admission. We hypothesized that a delayed, repeat ultrasound study (Secondary Ultrasound--SUS) will reveal additional intra-abdominal injuries and hemoperitoneum.

METHODS

We performed a prospective observational study of trauma patients at our Level I trauma center from April 2003 to December 2003. Patients underwent an initial ultrasound (US), followed by a SUS examination within 24 hours of admission. Patients not eligible for a SUS because of early discharge, operative intervention or death were excluded. All US and SUS exams were performed and evaluated by surgical/emergency medicine house staff or surgical attendings.

RESULTS

Five hundred forty-seven patients had both an initial US and a SUS examination. The sensitivity of the initial US in this patient population was 31.1% and increased to 72.1% on SUS (p < 0.001) for intra-abdominal injury or intra-abdominal fluid. The specificity for the initial US was 99.8% and 99.8% for SUS. The negative predictive value was 92.0% for the initial US and increased to 96.6% for SUS (p = 0.002). The accuracy of the initial ultrasound was 92.1% and increased to 96.7% on the SUS (p < 0.002). No patient with a negative SUS after 4 hours developed clinically significant hemoperitoneum.

CONCLUSION

A secondary ultrasound of the abdomen significantly increases the sensitivity of ultrasound to detect intra-abdominal injury.

Blunt Abdominal Trauma Patients: Can Organ Injury Be Excluded without Performing Computed Tomography?

PURPOSE

The purpose of this study was to determine whether admission non-computed tomography (CT) criteria can exclude intra-abdominal injury in stable patients sustaining blunt abdominal trauma.

METHODS

Seven hundred fourteen hemodynamically stable patients with suspicion of blunt abdominal trauma were included in the study. Admission data for clinical examination, sonography, routine laboratory studies, chest/pelvic radiographic findings, and Glasgow Coma Scale (GCS) score were recorded. Each patient underwent helical abdominal CT. Injuries were considered major if they required surgery or angiographic intervention. At the authors' institution, angiography is routinely performed if there is a splenic injury of American Association for the Surgery of Trauma grade II or higher or a liver injury of American Association for the Surgery of Trauma grade III or higher. Statistical analysis was performed to determine the value of isolated and combined clinical, radiologic, and laboratory parameters in depicting an intra-abdominal injury with regard to CT results and clinical follow-up.

RESULTS

The best combination of criteria to identify a major abdominal injury was obtained when sonography, chest radiography, and three laboratory parameters (serum glutamic oxaloacetic transaminase, white blood cell count, and hematocrit) were normal: 22% (129 of 589) of patients without major injuries fulfilled these criteria. The only combination of criteria that completely excluded intra-abdominal injury was obtained when clinical criteria combined with a Glasgow Coma Scale score > 13, bedside radiologic studies, and laboratory data were all normal, but only 12% (68 of 578) of patients without abdominal injury fulfilled these criteria.

CONCLUSION

After blunt abdominal trauma, admission non-CT criteria can at best identify 12% of patients without intra-abdominal injuries and 22% of patients without major injuries.

Blunt Abdominal Trauma:Does the Use of a Second-Generation Sonographic Contrast Agent Help to Detect Solid Organ Injuries?

OBJECTIVE

The objective of our study was to prospectively evaluate whether a second-generation sonography contrast agent (SonoVue) can improve the conspicuity of solid organ injuries (liver; spleen; or kidney, including adrenal glands) in patients with blunt abdominal trauma.

SUBJECTS AND METHODS

Two hundred ten consecutive hemodynamically stable trauma patients underwent both abdominal sonography and CT at admission. The presence of solid organ injuries and the quality of sonography examinations were recorded. Patients with false-negative sonography findings for solid organ injuries in comparison with CT results underwent control sonography. If a solid organ injury was still undetectable, contrast-enhanced sonography was performed. Findings of admission, control, and contrast-enhanced sonograms were compared with CT results for their ability to depict solid organ injuries. Contrast-enhanced sonography was also performed in patients in whom a vascular injury (pseudoaneurysm) was shown on admission or control CT.

RESULTS

CT findings were positive for 88 solid organ injuries in 71 (34%) of the 210 patients. Admission, control, and contrast-enhanced sonograms had a detection rate for solid organ injury of 40% (35/88), 57% (50/88), and 80% (70/88), respectively. The improvement in the detection rate between control and contrast-enhanced sonography was statistically significant (p = 0.001). After exclusion of low-quality examinations, contrast-enhanced sonography still missed 18% of solid organ injuries. Five vascular liver (n = 1) and spleen (n = 4) injuries (pseudoaneurysms) were detected on CT; all were visible on contrast-enhanced sonography.

CONCLUSION

Contrast-enhanced sonography misses a large percentage of solid organ injuries and cannot be recommended to replace CT in the triage of hemodynamically stable trauma patients. However, contrast-enhanced sonography could play a role in the detection of pseudoaneurysms.

Evaluation of a focused assessment with sonography for trauma protocol to detect free abdominal fluid in dogs involved in motor vehicle accidents

OBJECTIVE

To establish a focused assessment with sonography for trauma (FAST) protocol in dogs, determine whether FAST can be performed by veterinary clinicians without extensive ultrasonographic experience, and assess the frequency of free fluid (as determined via FAST) in the abdominal cavity of dogs following motor vehicle accidents (MVAs).

DESIGN

Prospective study.

ANIMALS

100 client-owned dogs evaluated within 24 hours of an MVA.

PROCEDURE

Dogs were placed in lateral recumbency for the FAST examination. To detect fluid in the abdomen, 2 ultrasonographic views (transverse and longitudinal) were obtained at each of 4 sites (just caudal to the xiphoid process, on the midline over the urinary bladder, and at the left and right flank regions).

RESULTS

In the 100 dogs evaluated via FAST, free abdominal fluid was detected in 45 dogs. In 40 of those 45 dogs, abdominocentesis was performed; hemoperitoneum and uroperitoneum were diagnosed in 38 and 2 dogs, respectively. Compared with dogs that had no free abdominal fluid detected via FAST, dogs that had free abdominal fluid detected via FAST had significantly higher heart rates and serum lactate concentrations and significantly lower PCVs and total solid concentrations.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicate that FAST is a simple and rapid technique that can be performed on dogs in an emergency setting to detect intra-abdominal free fluid and can be performed by veterinary clinicians with minimal previous ultrasonographic experience.

Massive haemorrhage from hepatic laceration with diaphragmatic laceration: a potential limitation of the FAST examination: case report

This report describes the case of a multitrauma patient who had life-threatening intraabdominal hemorrhage with a diaphragmatic laceration. This hemorrhage remained undetected by serial focus assessment with sonography for trauma (FAST) examination. The potential for intraabdominal blood to move through a diaphragmatic laceration to the pleural space may limit the development of hemoperitoneum, rendering the FAST examination misleading or producing a false-negative result. The use of the FAST examination is discussed along with its advantages and limitations.

Free Abdominal Fluid on Ultrasound in Unstable Pelvic Ring Fracture: Is Laparotomy Always Necessary?

BACKGROUND

In unstable pelvic ring fractures free abdominal fluid on ultrasound (US) may be caused by retroperitoneal hematoma that passes into the abdominal cavity or by an additional intraabdominal lesion. In this study a clinical pathway for the therapy of potentially combined lesions was analyzed.

PATIENTS AND METHODS

All patients treated in the ED for severe trauma underwent basic sonographical and radiologic diagnostics within 15 minutes. of admission. Data were prospectively documented. According to the treatment protocol unstable pelvic ring fractures with initial free fluid on US received laparotomy. Patients with stable vital conditions had abdominal CT-Scan before surgery.

RESULTS

1472 consecutive severely injured patients (ISS 20, age: 39 years) were included. Eighty subjects had sustained type B (47) or C (33) pelvic ring fracture. Early free abdominal fluid on US was absent in 49 cases. Three patients in this group required celiotomy later on, during ICU treatment. In 31 patients free fluid was present. All of them had laparotomy. Only one patient showed retroperitoneal hematoma alone, while all others had one or more significant lesions (rupture) that required surgical repair. Simultaneously with laparotomy pelvic stabilization was performed by external (19) or internal (6) fixation. In all cases with massive pelvic hemorrhage and free fluid in US bleeding was controlled by internal tamponade and external fixation.

CONCLUSION

The finding of intraperitoneal fluid on US in the emergency department strongly correlates with significant intraabdominal lesions requiring surgical intervention. Early laparotomy appears indicated in these cases. Shock control in pelvic bleeding can be sufficiently achieved by internal tamponade and external fixation.

Postcoital haemoperitoneum: a cause for shock

Postcoital haemoperitoneum rarely occurs without evident vaginal injury. A 21-year-old second gravida woman presented to the ED in shock with a history of 8 weeks amenorrhoea and abdominal pain of 20 h duration. The ultrasound examination revealed a live intrauterine pregnancy and fluid in peritoneal cavity. There was a history of coitus 2 hours prior to the onset of pain. At laparotomy, more than 2 L of free blood was found in the peritoneal cavity. A small bleeding peritoneal vessel in pouch of Douglas was identified and ligated.

The use of sonography versus computed tomography in the triage of blunt abdominal trauma: the European perspective

The management of the trauma-emergency patient has become an important political and economic issue and one of the major challenges of the industrialized countries. In Europe ultrasonography is always part of the basic work-up, following physical examination, whereas computed tomography (CT) remains a second-line investigation. Injury prevalence, radiation dose exposure, practicability, and costs are relevant considerations in our emergency departments, where we have a growing number of patients seeking medical attention. The radiologist's task is to decide which imaging modality is most appropriate after the clinical context has been taken into consideration. The clinical value of CT is unquestioned; what is questionable is only its systematic use. With the growing demand for trauma care, screening ultrasonography can lower the number of inappropriate CT examinations.

Controversies in emergency radiology. CT versus ultrasound in the evaluation of blunt abdominal trauma

There has been controversy regarding ultrasonography (US) versus CT in blunt abdominal trauma (BAT). Each modality has its strengths and weaknesses. US is fast and allows resuscitative efforts to proceed while the patient is being scanned. However, the sensitivity of US is inferior to that of CT, and there is user variability. CT is better at determining the extent, type, and grade of injury, resulting in a more tailored therapeutic plan and safe conservative management of many patients. However, CT involves ionizing radiation, cannot be performed portably, and requires only visual monitoring while scanning. Given each modality's strengths and weaknesses we conclude that CT is the preferred examination when the BAT patient is stable or moderately stable, enough to be taken to CT. If a BAT patient is unstable, US is beneficial in screening for certain injuries or large hemoperitoneum prior to an exploratory laparotomy.

Emergency ultrasound in trauma patients

US will be used more frequently in the future for the evaluation of traumatized patients. Previously,the main focus of the sonographic examination was for the detection of free fluid. Unstable patients with free fluid often can be triaged to the operation room without further imaging tests. In patients who are more stable or in whom US results are negative, CT is required. Based on recent studies, sonography has a sensitivity rate of approximately 40% in direct detection of solid organ injuries. In the future, however, with the use of contrast-enhanced agents, sonography may more reliably detect solid organ injuries. Within the chest, US has been shown to be helpful in detecting pleural effusions and may be useful in detecting pericardial effusions. US has been shown to be sensitive in detecting pneumothoraces in traumatized patients.

Sonographic patterns of intraperitoneal hemorrhage associated with blunt splenic injury

OBJECTIVE

To determine the correlation between sonographic detection of free fluid in the left upper quadrant and blunt splenic injury.

METHODS

A retrospective review was conducted of all consecutive emergency blunt trauma sonograms obtained at a level I trauma center from January 1995 to January 2001. Data were collected on demographics, free fluid location, and patient outcome. Injuries were determined from computed tomography, diagnostic peritoneal lavage, laparotomy, or a combination thereof.

RESULTS

A total of 4320 blunt trauma sonograms were obtained, and 596 patients (14%) had intra-abdominal injuries. The mean age was 33.7 +/- 19.1 years (range, 1-95 years), with 294 (49%) male and 302 (51%) female. There was no statistical difference between age, sex, or mechanism for all subgroups. There were 409 true-positive, 187 false-negative, 88 false-positive, and 3636 true-negative findings. Sensitivity of sonography for detecting all intra-abdominal injuries was 68%, and specificity was 97.6%; sensitivity for detecting isolated splenic injuries was 73.8%. Locations of free fluid in patients with nonsplenic injuries were compared with those in patients with splenic injuries. Isolated left upper quadrant free fluid was significantly associated with splenic injury (odds ratio = 3.0; P = .002), followed by diffuse free fluid (odds ratio = 2.1; P = .005). A subanalysis of isolated splenic injuries also revealed a significant association with left upper quadrant free fluid (odds ratio = 3.1; P = .007) and diffuse free fluid (odds ratio = 2.7; P = .0007).

CONCLUSIONS

Free fluid in the left upper quadrant is significantly associated with splenic injury. This finding should triage patients more rapidly to computed tomography, angiography, embolization, and laparotomy.

Splenic trauma: evaluation with contrast-specific sonography and a second-generation contrast medium: preliminary experience

OBJECTIVE

To report our experience in the assessment of splenic trauma with contrast-coded sonography and a second-generation contrast medium.

METHODS

From January to May 2002, 120 patients were studied with sonography for suspected splenic trauma. Twenty-five were selected for further imaging because of sonographic findings positive for splenic injury, findings positive for peritoneal fluid only, indeterminate findings, and negative findings with high clinical or laboratory suspicion. These patients underwent contrast-enhanced harmonic sonography and contrast-enhanced helical computed tomography.

RESULTS

Among the 25 patients studied, 6 had no spleen trauma at initial and follow-up evaluation. One patient had a hypoperfused spleen without parenchymal damage, and 18 had splenic injuries; these 19 patients were considered positive. Hemoperitoneum was identified by sonography, contrast-enhanced sonography, and contrast-enhanced computed tomography in 74% of the 19 positive cases. Perisplenic clots were recognized in 58% of the cases by computed tomography and in 42% by baseline and enhanced sonography. Splenic infarctions were found in 11% of cases by contrast-enhanced sonography and computed tomography; none was found by unenhanced sonography. Parenchymal traumatic lesions were identified in 12 of 18 patients with splenic injuries by unenhanced sonography, in 17 cases by contrast-enhanced sonography, and in all 18 cases by contrast-enhanced computed tomography. A minimal splenic lesion was found in the single patient with a false-negative contrast-enhanced sonographic finding. Contrast-enhanced sonography correlated appreciably better than unenhanced sonography in detecting injuries and in estimating their extent. Findings undetectable on unenhanced sonography were also noted: splenic hypoperfusion in 11% of positive cases on both contrast-enhanced sonography and contrast-enhanced computed tomography, contrast medium pooling in 21% of cases on both contrast-enhanced sonography and computed tomography, and contrast extravasation in 11% of cases on computed tomography and 5% on contrast-enhanced sonography.

CONCLUSIONS

Contrast-enhanced sonography is a promising tool in the assessment of splenic trauma. In institutions where sonography is used as the initial procedure, this technique may increase its effectiveness.

Blunt abdominal trauma: should US be used to detect both free fluid and organ injuries?

PURPOSE

To evaluate abdominal ultrasonography (US) for indirect (with free fluid analysis only) and direct (with free fluid and parenchymal analysis) detection of organ injury in patients with blunt abdominal trauma, with findings at computed tomography (CT) and/or surgery as the standard of diagnosis.

MATERIALS AND METHODS

Abdominal US was performed at hospital admission in consecutive patients with blunt abdominal trauma. The presence of free peritoneal fluid and organ injury were recorded and compared with results of abdominal CT in all hemodynamically stable patients. When US results were considered false-negative for free fluid or organ injury compared with CT results, repeat US was performed within 6 hours. Admission and second US results were compared with CT and/or surgical results to determine sensitivity, specificity, negative predictive value, and positive predictive value of US with regard to the presence of free intraperitoneal fluid and/or organ injury.

RESULTS

Two hundred five hemodynamically stable patients underwent abdominal US and CT. CT revealed free fluid in 83 patients and organ injury in 99. Thirty-one (31%) of 99 patients with organ injury did not have free fluid at CT. Three (10%) of the 31 patients required surgery or angiographic embolization. The sensitivity of admission US was 93% (77 of 83 cases) for the diagnosis of free fluid, 41% (39 of 99) for directly demonstrating organ injury, and 72% (71 of 99) for suggesting organ injury by means of both free fluid and organ analysis. At second US, these sensitivities were 96% (80 of 83 cases), 55% (54 of 99) and 84% (83 of 99), respectively.

CONCLUSION

US is highly sensitive for the detection of free intraperitoneal fluid but not sensitive for the identification of organ injuries. In hemodynamically stable patients, the value of US is mainly limited by the large percentage of organ injuries that are not associated with free fluid.

Not so FAST

BACKGROUND

Focused assessment with sonography for trauma (FAST) as a screening tool in the evaluation of blunt abdominal trauma will lead to underdiagnosis of abdominal injuries and may have an impact on treatment and outcome in trauma patients.

METHODS

From October 2001 to June 2002, a protocol for evaluating hemodynamically stable trauma patients with suspected blunt abdominal injury (BAI) admitted to our institution was implemented using FAST examination as a screening tool for BAI and computed tomographic (CT) scanning of the abdomen and pelvis as a confirmatory test. At the completion of the secondary survey, patients underwent a four-view FAST examination (Sonosite, Bothell, WA) followed within 1 hour by an abdominal/pelvic CT scan. The FAST examination was considered positive if it demonstrated evidence of free intra-abdominal fluid. Clinical, laboratory, and imaging results were recorded at admission, and FAST examination results were compared with CT scan findings, noting the discordance.

RESULTS

Patients with suspicion for BAI were evaluated according to protocol (n = 372). Thirteen cases were excluded for inadequate FAST examinations, leaving 359 patients for analysis. There were 313 true-negative FAST examinations, 16 true-positives, 22 false-negatives, and 8 false-positives. Using CT scanning as the confirmatory test for hemoperitoneum, FAST examination had a sensitivity of 42%, a specificity of 98%, a positive predictive value of 67%, a negative predictive value of 93%, and an accuracy of 92%; chi analysis showed significant discordance between FAST examination and CT scan (5.85%, < 0.001). Six patients with false-negative FAST examinations required laparotomy for intra-abdominal injuries; 16 patients required admission for nonoperative management of injury. Of the 313 true-negative FAST examinations, 19 patients were noted to have intra-abdominal injuries without hemoperitoneum and 11 patients were noted to have retroperitoneal injuries.

CONCLUSION

Use of FAST examination as a screening tool for BAI in the hemodynamically stable trauma patient results in underdiagnosis of intra-abdominal injury. This may have an impact on treatment and outcome in trauma patients. Hemodynamically stable patients with suspected BAI should undergo routine CT scanning.

Clinical importance of intraperitoneal fluid in patients with blunt intra-abdominal injury

The purpose of this study was to determine the prevalence of intraperitoneal fluid (IF) in blunt trauma patients with intra-abdominal injuries, to determine the rate of exploratory laparotomy in patients with and without IF, and to identify the location of this IF. We retrospectively reviewed the records of 604 patients with intra-abdominal injuries after blunt trauma who were admitted to a level 1 trauma center over a 42-month period. Patients were considered to have intra-abdominal injuries if an injury to the spleen, liver, urinary tract, pancreas, adrenal glands, gallbladder, or gastrointestinal tract was identified on abdominal computed tomography (CT) or at exploratory laparotomy. Patients were considered to have IF if fluid was identified on abdominal CT or during exploratory laparotomy. In patients undergoing abdominal CT or abdominal ultrasound (US), the specific location of the IF was identified. Four hundred forty-three (73%, 95% confidence interval [CI] 69 - 77%) of the 604 patients with intra-abdominal injuries had IF. Patients with IF had an increased risk of laparotomy (344/443 [78%] v 44/161 [27%], odds ratio = 9.2, 95% CI 6.1-13.9). Of the 539 patients undergoing abdominal CT or abdominal US, IF was identified in 389 (72%) and was visualized in the following locations: 258 of 389 (66%) in Morison's pouch, 216 of 389 (56%) in the left upper quadrant, 187 of 389 (48%) in the pelvis, and 139 of 390 (36%) in paracolic gutters. Three patients with IF visualized solely in the paracolic gutters underwent laparotomy. The majority of patients with intra-abdominal injuries have IF, and these patients are more likely to undergo laparotomy. Morison's pouch is the most common location for IF to be detected with radiologic imaging. However, visualization of the paracolic gutters with abdominal US may detect IF in patients with intra-abdominal injuries that would otherwise not be detected by US.

Multidetector CT: detection of active hemorrhage in patients with blunt abdominal trauma

OBJECTIVE

The aim of this study was to determine the imaging findings and the prevalence of active hemorrhage on contrast-enhanced multidetector CT in patients with blunt abdominal trauma.

MATERIALS AND METHODS

Contrast-enhanced multidetector CT images of 165 patients with blunt abdominal trauma were reviewed for the presence of extravasated contrast agent, a finding that represents active hemorrhage. The site and appearance of the hemorrhage were noted on multidetector CT images. These findings were compared with surgical and angiographic results or with clinical follow-up.

RESULTS

On multidetector CT images, active hemorrhage was detected in 22 (13%) of 165 patients with a total of 24 bleeding sites (14 intraperitoneal sites and 10 extraperitoneal sites). Active hemorrhage was visible most frequently as a jet of extravasated contrast agent (10/24 bleeding sites [42%]). Diffuse or focal extravasation was less frequently seen (nine [37%] and five [21%] bleeding sites, respectively). CT attenuation values measured in the aorta (mean, 199 H) were significantly higher than those measured in extravasated contrast material (mean, 155 H) (p < 0.001). Sixteen (73%) of 22 patients with active bleeding on multidetector CT images underwent immediate surgical or angiographic intervention. One patient received angiographic therapy 10 hr after undergoing multidetector CT, and five patients died between 1 and 3 hr after multidetector CT examination.

CONCLUSION

Active hemorrhage in patients after blunt abdominal trauma is most frequently visible as a jet of extravasated contrast agent on multidetector CT. When extravasation is detected, immediate surgical or angiographic therapy is required.

The focused abdominal sonography for trauma scan: pearls and pitfalls

OBJECTIVE

To review the state-of-the-art use of sonography in evaluating the patient with trauma.

METHODS

We reviewed our experience in performing more than 5000 sonographic examinations in the patient with trauma. The recent experience of other publications advocating newer applications of sonography in the patient with trauma are discussed and presented in a pictorial fashion.

RESULTS

The main focus of sonography in the patient with trauma has been in performance of the focused abdominal sonography for trauma scan. The focused abdominal sonography for trauma scan is usually performed in the patient with blunt abdominal trauma and is used to check for free fluid in the abdomen or pelvis. There are certain pitfalls that need to be avoided and certain limitations of the focused abdominal sonography for trauma scan that need to be recognized. These pitfalls and limitations are reviewed. More recently, sonography has been used to detect certain solid-organ injuries that have a variety of appearances. Thus, sonography may be used to localize the specific site of injury in these patients. More recently, sonography has been used to evaluate thoracic abnormalities in patients with trauma, including pleural effusions, pneumothoraces, and pericardial effusions.

CONCLUSIONS

The use of sonography in evaluating the patient with trauma has rapidly expanded in the past decade. Those using sonography in this group of patients should be aware of its many uses but also its potential pitfalls and limitations.

Blunt abdominal trauma in children: evaluation with emergency US

PURPOSE

To assess the accuracy of emergency abdominal ultrasonography (US) in the detection of both hemoperitoneum and parenchymal organ injury in children.

MATERIALS AND METHODS

Imaging findings were recorded prospectively in 744 consecutive children who underwent emergency US from January 1995 to October 1998; free fluid and parenchymal abnormalities of specific organs were also noted. Patients with intraabdominal injuries were identified retrospectively. Computed tomographic (CT) findings, intraoperative findings, and clinical outcome were compared with the initial US findings. Sensitivity, specificity, and positive and negative predictive values were calculated for patients who underwent CT, laparotomy, or both after US.

RESULTS

Seventy-five (10%) of 744 patients had intraabdominal injuries, and US depicted free fluid in 42 of them. US had 56% sensitivity, 97% specificity, 82% positive predictive value, and 91% negative predictive value for detection of hemoperitoneum alone. US helped identify parenchymal abnormalities that corresponded to actual organ injury without accompanying free fluid in nine patients (12%). Inclusion of identification of parenchymal organ injury at US increased the sensitivity of US to 68%, with an accuracy of 92%.

CONCLUSION

US for blunt abdominal trauma in children is highly accurate and specific, but moderately sensitive, for detection of intraabdominal injury.

Sonographic assessment of blunt abdominal trauma: a 4-year prospective study

PURPOSE

Emergency abdominal sonography has become a common modality worldwide in the evaluation of injuries caused by blunt trauma. The sensitivity of sonography in the detection of hemoperitoneum varies, and little is known about the accuracy of sonography in the detection of injuries to specific organs. The purpose of this study was to determine the overall accuracy of sonography in the detection of hemoperitoneum and solid-organ injury caused by blunt trauma.

METHODS

From January 1995 to October 1998, 3,264 patients underwent emergency sonography at our institution to evaluate for free fluid and parenchymal abnormalities of specific organs caused by blunt trauma. All patients with intra-abdominal injuries (IAIs) were identified, and their sonographic findings were compared with their CT and operative findings, as well as their clinical outcomes.

RESULTS

Three hundred ninety-six (12%) of the 3,264 patients had IAIs. Sonography detected free fluid presumed to represent hemoperitoneum in 288 patients (9%). The sonographic detection of free fluid alone had a 60% sensitivity, 98% specificity, 82% positive predictive value, and 95% negative predictive value for diagnosing IAI. The accuracy was 94%. Seventy patients (2%) had parenchymal abnormalities identified with sonography that corresponded to actual organ injuries. The sensitivity of the sonographic detection of free fluid and/or parenchymal abnormalities in diagnosing IAI was 67%.

CONCLUSIONS

Emergency sonography to evaluate patients for injury caused by blunt trauma is highly accurate and specific. The sonographic detection of free fluid is only moderately sensitive for diagnosing IAI, but the combination of free fluid and/or a parenchymal abnormality is more sensitive.

From the RSNA refresher courses: focused abdominal US for trauma

Focused abdominal ultrasonography (US) has been introduced in Europe as a method to evaluate blunt abdominal trauma. The main focus of the examination is detection of free fluid in the abdomen secondary to injury of the abdominal organs. The examination takes only a few minutes to perform. In the authors' experience, trauma patients in unstable condition and in whom significant free fluid is detected are immediately taken to the operating room for surgical exploration without undergoing computed tomographic (CT) correlation. The authors have also used US to identify the specific site of organ injury. Injuries to solid organs such as the liver, spleen, and kidney that are identified with US usually appear heterogeneous or hyperechoic. A hematoma surrounding the injured organ may appear echogenic or hypoechoic. However, pitfalls of focused abdominal US for trauma include failure to show contained solid-organ injuries; injuries to the diaphragm, pancreas, and adrenal gland; and some bowel injuries. Thus, negative findings at US do not exclude an intraperitoneal injury, and close clinical observation or CT is warranted.

Does the presence of ultrasound really affect computed tomographic scan use? A prospective randomized trial of ultrasound in trauma

OBJECTIVE

There is a paucity of evidence demonstrating that emergency department (ED) ultrasound changes clinical practice in trauma patients. We hypothesized that the presence of ultrasound would affect clinical decision making as evidenced through abdominal computed tomographic (CT) scan use in blunt multiple trauma patients.

METHODS

This study used a prospective randomized format in an urban county ED with Level II trauma center status (ED census, 72,000 patients per year). Participants were patients with multiple blunt injuries meeting trauma center triage criteria. Patients were randomized to receive either abdominal ultrasound or no ultrasound (control) during initial ED resuscitation. The primary outcome variable was use of abdominal CT scan in patients with and without ultrasound.

RESULTS

Two hundred eight patients were enrolled. The mean age was 40 +/- 18 years, and 62% were men. Mechanism of injury was motor vehicle crash, 56%; automobile versus pedestrian, 18%; motorcycle crash, 16%; falls, 10%; and other, 10%. One hundred four ultrasound and 104 control patients were analyzed. There were no apparent differences between ultrasound and control groups in demographics, injury type, or Injury Severity Score. Fifty-four of 104 (52%) of the control group received abdominal CT scans versus 37 of 104 (36%) abdominal CT scans for the ultrasound group; mean difference in proportions was 15.9 (p < 0.01; 95% confidence interval, 2.6-29.1).

CONCLUSION

In this trial, the routine use of abdominal ultrasound in the evaluation of patients with multiple blunt injuries resulted in significantly fewer abdominal CT scans being obtained. A larger trial is needed to more clearly define the clinical and financial impact of ultrasound in the management of blunt abdominal trauma.

The routine use of sonography in penetrating torso injury is beneficial

BACKGROUND

Torso sonography (focused assessment with sonography for trauma [FAST]) has been added to our protocols for the evaluation of penetrating torso injury. The purpose of this study was to evaluate our recent experience and determine whether the use of FAST is beneficial.

METHODS

From January 1999 to January 2000, patients with penetrating torso injury and no clinical indication for surgery were evaluated by sonography with a selective use of other investigations. FAST consisted of sonographic views of the peritoneum and/or pericardium to determine the presence or absence of fluid.

RESULTS

During the study period, there were 238 victims of penetrating injury assessed by our trauma service, and sonography was performed in 72 (30%) patients as per our protocols. There were 31 stab, 37 gunshot/shotgun and, and 4 puncture wounds. Thirty-eight patients had peritoneal views, 6 patients had pericardial views, and 28 patients had both pericardial and peritoneal views obtained. Thirteen of 66 patients had free fluid in the peritoneal cavity and 12 of the 13 patients had a therapeutic laparotomy. No peritoneal fluid was seen in 53 of 66 patients, of whom 6 had abdominal injuries, 5 requiring surgery for diaphragm or bowel injuries. The sensitivity of FAST alone for abdominal injury was 67%, specificity was 98%, positive predictive value was 92%, and negative predictive value was 89%. Pericardial fluid was seen in 3 of 34 patients; one had a heart wound and two had negative pericardial windows. All 31 patients without pericardial fluid recovered without surgery.

CONCLUSION

The routine use of sonography in penetrating torso injury is beneficial. The detection of pericardial or peritoneal fluid is clinically useful. However, a negative FAST examination does not exclude abdominal injury, such as a diaphragm or hollow viscus wound, and further investigation or close follow-up is required.