Sonography in blunt abdominal trauma: a preliminary progress report

Noninvasive Hemodynamic Monitoring in the Intensive Care Unit

This article reviews the clinically available devices that have been approved for noninvasive hemodynamic monitoring in critically ill patients. In addition this article reviews some of the surrogate markers that can be used to assess adequacy of cardiac output.

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.

Emergency room management of patients with blunt major trauma: evaluation of the multislice computed tomography protocol exemplified by an urban trauma center

BACKGROUND

The early clinical management of patients with major trauma still represents a challenge. To clinically evaluate the full extent of a patient's injuries is difficult, especially when the patient is unconscious. Before December 2002, trauma patients admitted to our emergency room (ER) underwent a diagnostic protocol including physical examination, conventional radiography (CR), sonography and further procedures if necessary. After the installation of a MSCT scanner, all trauma patients underwent the "MSCT protocol" immediately after admission. The aim of the study was to compare the "MSCT-protocol" as it is performed at our institution, with the "Pre-MSCT-protocol".

METHODS

We compared 185 patients undergoing the "Pre MSCT-protocol" with 185 patients undergoing "MSCT protocol". We evaluated the efficacy, speed and accuracy of the "MSCT protocol" using several variables. Time periods from admission to the ER to admission to the intensive care unit were compared as well as outcome parameters such as length of ICU stay, ventilation period and rates of organ. Dichotomous data were analyzed by Chi-square analysis; continuous data were analyzed by Student's t test. Any values of p < 0.05 were considered significant for any test.

RESULTS

No significant differences were found regarding demographic data. The full extent of injuries was definitively diagnosed after 12 +/- 9 minutes in 92.4% of the "MSCT protocol" cohort. In only 76.2% of "Pre-MSCT protocol" cohort definitive diagnosis was possible after 41 +/- 27 minutes. Total ER time was 104 +/- 21 minutes with the "Pre-MSCT protocol" and 70 +/- 17 minutes with "MSCT protocol" (p < 0.05). "Pre-MSCT protocol" patients had a significantly longer ICU stay than "MSCT protocol" patients (p < 0.05). "MSCT protocol" patients had significantly fewer ventilation days (14.3 vs. 10.9 days). Furthermore, rates of organ failure were lower in patients undergoing the "MSCT protocol".

CONCLUSION

We could demonstrate that immediate MSCT in patients with blunt major trauma leads to more accurate and faster diagnosis, and reduction of early clinical time intervals. We also observed a reduction in ventilation, ICU, and hospital days, and in organ failure rates, though this might have been partly due to small differences in case mix. The "MSCT protocol" algorithm seems to be safe and effective.

Accuracy of physical and ultrasonographic examinations by emergency physicians for the early diagnosis of intraabdominal haemorrhage in blunt abdominal trauma

OBJECTIVE

To determine the accuracy of physical examination and ultrasonographic evaluation performed by emergency physicians in cases of blunt abdominal trauma for the early diagnosis of intraabdominal haemorrhage.

METHODS

In this clinical prospective study, trauma patients were evaluated with four-quadrant ultrasonography by emergency physicians after initial stabilisation and physical examination. Diagnoses based on demographic data, physical examination and emergency physician's ultrasonography were compared with the subsequent clinical course.

RESULTS

A total of 442 patients participated in the study. The sensitivity and specificity of emergency physician's ultrasonographic examination to detect intraabdominal haemorrhage were 86 and 99%, respectively. Pre-test sensitivity and specificity of physical examination to detect intraabdominal haemorrhage were 39 and 90%, respectively.

CONCLUSIONS

Physical examination was not a reliable method to detect intraabdominal haemorrhage in cases of blunt abdominal trauma. In contrast, abdominal ultrasonography performed by emergency physicians was a reliable diagnostic tool. Emergency physicians should be familiar with abdominal ultrasonographic examination, which should be routine in cases of blunt abdominal trauma.

History of emergency and critical care ultrasound: The evolution of a new imaging paradigm

The tradition of clinical ultrasound in the hands of physicians who provide critical care to the most acutely ill patients stretches back into the 1980s and is rich with experiences from surgical, emergency medicine, and other practices. Now, as critical care ultrasound explodes around the world, it is important to realize the path its development has taken and learn from trials and tribulations of early practitioners in the field. The development and battles for the right to use ultrasound at the patient's bedside for >20 yrs is described in relation to its emergency medicine and surgical origins. Approaches to education, scanning, documentation, and organization at the national and regional levels are described.

The accuracy of focused assessment with sonography in trauma (FAST) in blunt trauma patients: experience of an Australian major trauma service

Focused assessment with sonography for trauma (FAST) is a method for detecting haemoperitoneum in trauma patients on initial assessment in the Emergency Department. The aim of this paper is to present an Australian trauma centre's experience with FAST as a tool to screen for intraabdominal free fluid in patient's sustaining blunt truncal trauma.

METHOD

Over a 63-month period, FAST scans were prospectively studied and compared with findings from a gold-standard investigation, either computed tomography (CT) or laparotomy.

RESULTS

463 FAST results were collected prospectively from 463 patients. 53 scans were excluded due to lack of a corresponding confirmatory gold-standard test. Overall sensitivity, specificity, positive and negative predictive values for FAST in detecting free fluid were 78%, 97%, 91%, 93%, respectively. Analysis of the credentialed operators demonstrated an improvement in accuracy (sensitivity 80%, specificity 100%, positive predictive value 100%, negative predictive value 94%). These findings are comparable with documented international experience.

CONCLUSION

The study demonstrates that the use of non-radiologist performed FAST in the detection of free fluid is safe and accurate within an Australian Trauma Centre.

Critical care issues in the early management of severe trauma

Violent trauma and road traffic injuries kill more than 2.5 million people in the world every year, for a combined mortality of 48 deaths per 100,000 population per year. Most trauma deaths occur at the scene or in the first hour after trauma, with a proportion from 34% to 50% occurring in hospitals. Preventability of trauma deaths has been reported as high as 76% and as low as 1% in mature trauma systems. Critical care errors may occur in a half of hospital trauma deaths, in most of the cases contributing to the death. The most common critical care errors are related to airway and respiratory management, fluid resuscitation, neurotrauma diagnosis and support, and delayed diagnosis of critical lesions. A systematic approach to the trauma patient in the critical care unit would avoid errors and preventable deaths.

Evaluation of focussed assessment with sonography in trauma (FAST) by UK emergency physicians

OBJECTIVES

To evaluate the introduction of a focussed assessment with sonography in trauma (FAST) scan into the early assessment of trauma patients in the UK.

METHODS

The setting was an inner city teaching hospital emergency department (annual attendance 100,000). All patients aged 16 or over admitted to the resuscitation room after blunt trauma were included in a prospective observational study. Patients had a FAST scan performed at the end of the primary survey. Results were compared to results of other investigations, laparotomy, postmortem examination, or observation.

RESULTS

153 patients were entered into the study. The sensitivity of the FAST scan was 78% and specificity was 99%.

CONCLUSION

FAST is a highly specific "rule in" technique and is useful in the initial assessment of trauma patients. Emergency physicians can perform FAST after a brief training period.

FAST ultrasound as an adjunct to triage using the START mass casualty triage system: a preliminary descriptive system

OBJECTIVE

To determine whether the FAST examination might be a useful adjunct to simple triage and rapid treatment (START) in the secondary triage of mass-casualty victims already classified as delayed (Yellow).

METHODS

A retrospective chart review was conducted of all adult trauma patients evaluated by the trauma surgery service at a level 1 trauma center between January 1 and December 31, 2003. Patients were retrospectively triaged to one of three START categories: immediate (Red), delayed (Yellow), or expectant (Black). The FAST results were obtained from the medical records.

RESULTS

FAST results were available for 359 patients, of which 27 were classified as positive. Twenty (6.9%) of 286 patients retrospectively triaged as delayed (Yellow) had positive FAST studies. Of these, six underwent operative intervention within 24 hours of arrival. A total of 232 patients had both FAST and computed tomography (CT) studies performed, of which 19 FAST studies were inconclusive. In the remaining 213 patients, six of 27 had falsely positive studies, while 24 of 186 had falsely negative studies.

CONCLUSIONS

Portable ultrasound technology might have identified 20 delayed (Yellow) patients with evidence of hemoperitoneum, thereby expediting evacuation to definitive care. However, only 30% of these patients subsequently underwent an operative intervention within 24 hours of arrival. Both over- and undertriage were significant problems. As such, the current study does not support the routine use of FAST ultrasound as a secondary triage tool.

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.

Ultrasonography for Interval Assessment in the Nonoperative Management of Hepatic Trauma

Abdominal ultrasonography (US) is gaining widespread acceptance as a valuable diagnostic tool in the initial evaluation of trauma victims. We investigated the utility of US as a follow-up radiologic study in nonoperative hepatic trauma. Patients with liver injury designated for non-operative management were prospectively studied over a 2-year period at our primary adult resource center for trauma. Computed tomography (CT) and radiologist-performed US were obtained at admission and at 1 week. The ability of US to detect lesions, fluid, and complications was evaluated by comparing with the corresponding CT. Twenty-five hepatic trauma patients in the study were successfully managed nonoperatively and had both initial and follow-up US and CT scans: 1 (4%) grade I, 5 (20%) grade II, 7 (28%) grade III, 7 (28%) grade IV, and 5 (20%) grade V. Four complications developed [biloma (3) and biliary fistula (1)] in 3 patients with grade IV injury and 1 with a grade II injury. Interval US appropriately detected a complication or confirmed the absence of complication in all (13/13, 100%) patients with low-grade (I–III) injury and only missed a small biloma in one patient with a grade IV injury. Interval US and CT agreement was 92 per cent for change in hemoperitoneum or parenchymal lesion. Ultrasonography is a convenient imaging modality in the evaluation of hepatic trauma. US is sufficient to detect or exclude complications in low-grade injuries. In high-grade injuries, US may be an adjunct to CT for definitive interval assessment.

Pelvic free fluid: clinical importance for reproductive age women with blunt abdominal trauma

OBJECTIVE

To evaluate the importance of isolated pelvic free fluid (FF) detected by ultrasound examination in pregnant patients and in non-pregnant reproductive age women with blunt abdominal trauma (BAT).

METHODS

Reproductive age women aged 10-50 years who presented with BAT and underwent focused abdominal sonography for trauma (FAST) from January 1995 to June 2002 at a Level 1 trauma center were included. Patients were assigned to four groups according to the location of FF detected by ultrasound (Group 1, no FF; Group 2, FF in pelvis; Group 3, FF in abdomen; Group 4, FF in abdomen and pelvis). Ultrasound findings were compared with intra-abdominal and pelvic injuries detected by computed tomography and/or laparotomy. Pair-wise comparison was performed using a Fisher's exact test.

RESULTS

Ultrasound detection of FF in the abdomen alone or FF in the abdomen and pelvis was significantly associated with intra-abdominal injury (IAI) compared to those without FF (P < 0.001) for both pregnant and non-pregnant reproductive age women. FF isolated to the pelvis was also associated with a higher injury rate compared to no FF in pregnant women (30% vs. 3%, P = 0.005) and in non-pregnant reproductive age women (39.5% vs. 3.7%, P < 0.001).

CONCLUSIONS

In reproductive age women with BAT, ultrasound detection of FF in the abdomen alone, in both the abdomen and pelvis, or isolated to the pelvis is associated with a higher IAI rate. Therefore, isolated FF in the pelvis should not necessarily be considered physiological in pregnant and non-pregnant patients with BAT.

Bedside Ultrasonography in the ICU

This is the second of a two-part review on the application of bedside ultrasonography in the ICU. In this part, the following procedures will be covered: (1) echocardiography and cardiovascular diagnostics (second part); (2) the use of bedside ultrasound to facilitate central-line placement and to aid in the care of patients with pleural effusions and intra-abdominal fluid collections; (3) the role of hand-carried ultrasound in the ICU; and (4) the performance of bedside ultrasound by the intensivist. The safety and utility of bedside ultrasonography performed by adequately trained intensivists has now been well demonstrated. This technology, as a powerful adjunct to the physical examination, will become an indispensable tool in the management of critically ill patients.

Prospective analysis of the effect of physician experience with the FAST examination in reducing the use of CT scans

OBJECTIVE

The objective of this study was to examine the effect of ultrasound experience level on emergency physicians' Focused Assessment with Sonography for Trauma (FAST) exam accuracy and emergency physicians' confidence in using FAST findings to assist in managing patients with blunt trauma.

METHODS

This prospective, consecutive enrolment study evaluated adult trauma team activation blunt trauma patients. Based on the number of post-training FAST exams carried out, 11 attending emergency physicians were grouped into A (<25 exams, n = 4), B (26-50 exams, n = 4) or C (>50 exams, n = 3). The FAST exam was carried out prior to other diagnostic studies. The emergency physicians were asked to prospectively judge their perception of the need for surgery, abdominal CT or no further tests. All study patients ultimately underwent CT, diagnostic peritoneal lavage or laparotomy. Among each physician group, the number of subsequent CT scans deemed necessary by the emergency physician after a 'normal' FAST was calculated and compared.

RESULTS

Accuracy was greatest in group C. Sixty-nine of 80 patients in group A had a normal FAST exam; emergency physicians deemed CT necessary in 68/69 cases (99%; confidence interval [CI] 92-100%). Eighty-two of 98 patients in group C had a normal FAST exam; emergency physicians deemed CT necessary in 19/82 cases (23%; CI 15-34%). Physicians in groups B and C were less likely to order CT after a normal FAST than group A (P < 0.001).

CONCLUSIONS

FAST accuracy was greatest among more experienced emergency physicians. A normal FAST exam assisted more experienced emergency physicians with the perceived need to order significantly fewer CT scans than less experienced emergency physicians.

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.

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.

Ultrasound in abdominal trauma

This article reviews current issues regarding the Focused Assessment with Sonography for Trauma (FAST) examination. Technical performance issues, decision-making and practice algorithms, fluid volume and scoring systems, proficiency and training, and the role of the FAST in pediatric trauma are covered. This article examines the FAST examination from a practical, evidenced-based stand-point.

Surgeon-performed ultrasound in the ICU setting

Evaluation of critically ill patients is often challenging due to altered sensorium, underlying disease, and the presence of multiple drains or monitoring devices. In such circumstances, the ability of physicians to perform ultrasound examinations in the intensive care unit provides a useful diagnostic and therapeutic adjunct. In this article,we review the application of surgeon-performed ultrasonography in the evaluation and management of critically ill patients.

Critical concepts in abdominal injury

Missed intra-abdominal injuries are among the most frequent causes of potentially preventable trauma deaths. The evaluation and management of abdominal trauma is dependant on multiple factors, including mechanism of injury, location of injury, hemodynamic status of the patient, neurologic status of the patient, associated injuries, and institutional resources.

The benefit of routine thoracic, abdominal, and pelvic computed tomography to evaluate trauma patients with closed head injuries

BACKGROUND

The evaluation of multitrauma patients for blunt truncal injuries remains open for debate. We sought to evaluate the role of routine computed tomography (CT) of the chest, abdomen, and pelvis as a screening tool for patients already undergoing cranial CT studies.

METHODS

Charts of blunt trauma patients admitted from June 2000 to June 2001 were reviewed for demographics, Glascow Coma Scale (GCS), physical and radiological findings, and length of stay.

RESULTS

Our study found that 38% of patients undergoing cranial CT scanning had a unexpected finding on body scans. Changes were made in 26% of the study group because results found on the adjuvant CTs.

CONCLUSIONS

Additional body CTs add minimal cost to the care of trauma patients but can significantly change the management. We believe it is beneficial to perform routine body CT examinations when performing cranial imaging for blunt head injury.

Imaging of renal trauma

Trauma is a major cause of death and disability and renal injuries occur in up to 10% of patients with significant blunt abdominal trauma. Patients with penetrating trauma and hematuria, blunt trauma with shock and hematuria, or gross hematuria warrant imaging of the urinary tract specifically and CT is the preferred modality. If there is significant perinephric fluid, especially medially, or deep laceration, delayed images should be obtained to evaluate for urinary extravasation. Most renal injuries are minor, including contusions, subcapsular and perinephric hematoma, and superficial lacerations. More significant injuries include deep lacerations, shattered kidney, active hemorrhage, infarctions, and vascular pedicle and UPJ injuries. These injuries are more likely to need surgery or have delayed complications but may still often be managed conservatively. The presence of urinary extravasation and large devitalized areas of renal parenchyma, especially with associated injuries of intraperitoneal organs, is particularly prone to complication and usually requires surgery. Active hemorrhage should be recognized because it often indicates a need for urgent surgery or embolization to prevent exsanguination.

Fluid-filled bowel mimicking hemoperitoneum: a false-positive finding during sonographic evaluation for trauma

This case report describes a patient who presented to the Emergency Department (ED) after a high-speed motor vehicle crash (MVC), whose initial ultrasound examination was interpreted as being positive for fluid in Morison's pouch. Subsequent ultrasound examinations and computed tomography scans further delineated this finding to be fluid-filled bowel juxtaposed between the liver and right kidney. With greater implementation of ED ultrasound, it is important to identify entities that cause false-positive and false-negative examinations.

The role of elevated liver transaminase levels in children with blunt abdominal trauma

The role of serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) levels on intra-abdominal injury in children has not been adequately studied. In this report, the accuracy of these tests in predicting the degree and extend of intra-abdominal and hepatic injury in children with blunt abdominal trauma was investigated.Eighty-seven haemodynamically stable children with multiple trauma were prospectively evaluated. The SGOT and SGPT of patients with and without abdominal trauma (Groups I and II) were compared. Patients with and without radiologically verified intra-abdominal injury were further compared (Groups Ib and Ia). There was significant difference in SGOT and SGPT levels of Groups I and II. SGOT and SGPT levels were 333.6+/-283.8 and, 197.5+/-192.5 U/l, respectively in Group Ib; but 84.2+/-55.9, 43+/-29.8 U/l in Group Ia (P<0.001). In all patients with radiologically detected intra-abdominal pathology SGOT and SGPT levels were above 110.5 and 63.5 U/l, respectively. In patients with hepatic injury SGOT level was above 500 U/l and, SGPT level was above 300 U/l. Statistically significant positive correlation was found between radiologically detected intra-abdominal pathology and increased SGOT (above 110.5 U/l) and SGPT (above 63.5 U/l) levels (P<0.05). These data indicated that the SGOT and SGPT levels were significantly higher in patients with intra-abdominal injury even in the absence of hepatic injury. We suggest that liver function tests may be used as screening tests in children with blunt abdominal trauma in addition to physical abdominal examination. A sudden rise up to 110.5 U/l in SGOT and 63.5 U/l in SGPT indicate an intra-abdominal injury and severe hepatic injury should be suspected with higher levels of SGOT and SGPT.

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.

Focused assessment with sonography for trauma patients by clinicians: Initial experience and results

OBJECTIVES

To describe the establishment of a service to provide bedside focused assessment sonography in trauma and to evaluate the service to date.

SETTING

Emergency department of an urban trauma centre.

METHODS

A prospective study of trauma patients who received a focused assessment sonography in trauma examination performed by a clinician managing the trauma in the emergency department. Accuracy was determined by comparing the scan interpretation with abdomino-pelvic computerized tomography, laparotomy or postmortem examination.

RESULTS

The study period ran from 1 January 2000 to 11 September 2001 inclusive (20 months). One hundred and forty patients were included, with a final diagnosis established by computerized tomography (n = 124) and/or laparotomy (n = 18). There were 26 true-positives, 101 true-negatives, two false-positives and 11 false-negatives. Ten of the false-negative studies were performed by clinicians who had not reached accreditation. The sensitivity of focused assessment sonography in trauma was 70%, specificity 98% and diagnostic accuracy 91%.

CONCLUSIONS

We have described the implementation of a clinician-based focused assessment sonography in trauma service within the emergency department with the support of radiology/ultrasound and trauma service. Processes for credentialling, quality assurance and training need to be in place. Significant issues exist with the length of time it takes clinicians to reach accreditation, in order that a critical mass of clinicians exists to provide a consistent service. The credentialling process should mandate a minimum number of supervised examinations.

Emergency ultrasound credentialling for focused assessment sonography in trauma and abdominal aortic aneurysm: A practical approach for Australasia

OBJECTIVE

Focused assessment with sonography for trauma and emergency ultrasound for abdominal aortic aneurysm are now practiced widely by non-radiologists in emergency departments worldwide. Various credentialling programs have been proposed for novice sonographers; however, their feasibility has been questioned. We adopted the Australasian College for Emergency Medicine (ACEM) credentialling process for emergency ultrasound to determine whether it is feasible for emergency physicians in the Australasian environment.

METHODS

Three full-time emergency medicine specialists and a post-Fellowship Examination trainee at Auckland Hospital undertook the credentialling process.

RESULTS

All four participants had sufficient scans to complete the process after 16 months. Accuracy for focused assessment with sonography for trauma, 90% (95% CI 83-95%), and abdominal aortic aneurysm, 99% (95% CI 90-100%), is similar to that previously reported.

CONCLUSION

The ACEM credentialling process for focused assessment with sonography for trauma and abdominal aortic aneurysm is practical and achievable for emergency medicine specialists working in the Emergency Department at Auckland Hospital. Further studies are necessary to determine whether this holds true for other major trauma centres in Australasia.

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.

The Role of Positive Examinations in Training for the Focused Assessment Sonogram in Trauma (FAST) Examination

The purpose of this study is to determine whether the inclusion of known positive patients to the practical portion of a Focused Assessment Sonogram in Trauma (FAST) training course improves overall training and increases FAST accuracy. This is a prospective double-blind design. Original course participants (PRE) underwent a 2-hour didactic session and practicum with ten normal volunteers. Modified course participants (POST) additionally imaged five peritoneal dialysis (PD) patients to simulate positive examinations. The practitioners (six PRE and five POST) were compared as to their ability to detect and quantify intraperitoneal fluid (0–2000 cc) in nine PD patients during a double-blind prospective examination. Test results were reported as positive or negative. Positive results were further quantified by volume. Each practitioner performed ten examinations. Data for inexperienced clinicians are presented. Sensitivity for detecting ≤750 cm3 was 45 per cent PRE and 87 per cent POST ( P = 0.02). Accuracy in quantifying volume within 250 cm3 was 38 per cent PRE and 44 per cent POST (not significant). FAST accuracy for inexperienced sonographers—particularly in diagnosing smaller volumes—can be improved significantly by including positive studies in training. Exposure to positive FAST examinations during training improves the learning curve. With the growing dependency on FAST to accurately triage blunt abdominal trauma safe and effective FAST training should consist of didactic education and a practical portion that includes positive studies. When screened properly PD patients can be used effectively to demonstrate positive FAST studies.

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.

Current use and perceived utility of ultrasound for evaluation of pediatric compared with adult trauma patients

OBJECTIVE

The objective of this study was to evaluate the current use and perceived utility of ultrasound in the assessment of pediatric compared with adult trauma patients.

METHODS

A questionnaire was developed and mailed to 72 pediatric emergency physicians, 120 general emergency physicians, and 117 trauma attendings at 240 institutions.

RESULTS

Of 309 surveys, 234 (75%) were completed. Ultrasound was available to 169 of 234 (72%) of the physicians, and 122 of 169 (72%) were performing the Focused Assessment by Sonography for Trauma examination to evaluate trauma patients. Seventy-three percent (110/150) of general emergency and trauma surgeons reported that ultrasound was available equally with or more readily than computed tomography (CT) scan. Only 26% (5/19) of pediatric emergency attendings considered ultrasound equally available with CT scan, and none considered it more readily available than CT scan. Ninety-two percent (137/149) of general emergency and trauma attendings responding to the question about utility considered ultrasound somewhat useful to extremely useful for assessing adult trauma patients, and 77% considered it useful for pediatric patients. Only 57% (12/21) of pediatric emergency attendings responding to the same question perceived ultrasound as useful for pediatric trauma evaluations.

CONCLUSIONS

We conclude that ultrasound for the assessment of trauma patients is widely used by general emergency physicians and trauma surgeons, whereas pediatric emergency physicians report less use and perceived utility.

The hand-held FAST: experience with hand-held trauma sonography in a level-I urban trauma center

AIMS

To describe the effectiveness of a portable hand-held ultrasound machine when used by clinicians in the early evaluation and resuscitation of trauma victims.

METHODS

The study was a prospective evaluation in a level-I urban trauma center. The focussed assessment with sonography for trauma is a specifically defined examination for free fluid known as the focused assessment with sonography for trauma (FAST) exam. Seventy-one patients had a hand-held FAST (HHFAST) examination performed with a Sonosite 180, 2.4 kg ultrasound machine. Sixty-seven examinations were immediately repeated with a Toshiba SSH 140A portable floor-based machine. This repeat scan (formal FAST or FFAST) was used as a comparison standard between the devices for study purposes. Four patients had a HHFAST only, all with positive result, two being taken for immediate laparotomy, and two having a follow-up computed tomographic (CT) scan. Patient follow-up from other imaging studies, operative intervention, and clinical outcomes were also compared to the performance of each device.

RESULTS

There were 58 victims of blunt, and 13 of penetrating abdominal trauma. One examination was indeterminate using both machines. The apparent HHFAST performance yielded; sensitivity, specificity, positive predictive value, negative predictable value, and accuracy (S, S, PPV, NPV, A) of 83, 100, 100, 98, 98%. Upon review, a CT scan finding and benign clinical course found the HHFAST diagnosis to be correct rather than the FFAST in one case. Considering the ultimate clinical course of the patients, yielded a (S, S, PPV, NPV, A) of 78, 100, 100, 97, and 97% for the HHFAST and 75, 98, 86, 97, and 96% for the FFAST. Statistically, there was no significant difference in the actual performance of the HHFAST compared to the FFAST in this clinical setting.

DISCUSSION

Hand-held portable sonography can simplify early and accurate performance of FAST exams in victims of abdominal trauma.

Evaluating Blunt Abdominal Trauma with Sonography: A Cost Analysis

Ultrasonography (US) is becoming increasingly utilized in the United States for the evaluation of blunt abdominal trauma (BAT). The objective of this study was to assess the cost impact of utilizing US in the evaluation of patients with BAT in a major trauma center. All patients sustaining BAT during a 6-month period before US was used at our institution (Jan–Jun 1993) were compared to BAT patients from a recent period in which US has been utilized (Jan–Jun 1995). The numbers of US, computed tomography (CT), and diagnostic peritoneal lavage (DPL) were tabulated for each group. Financial cost for each of these procedures as determined by our finance department were as follows: US $96, CT $494, DPL $137. These numbers are representative of actual hospital expenditures exclusive of physician fees as calculated in 1994 U.S. dollars. Cost analysis was performed with t test and chi squared test, and significance was defined as P < 0.05. There were 890 BAT admissions in the 1993 study period and 1033 admissions in the 1995 study period. During the 1993 period, 642 procedures were performed on the 890 patients to evaluate the

abdomen: 0 US, 466 CT, and 176 DPL (see table). This compares to 801 procedures on the 1033 patients in 1995: 552 US, 228 CT, and 21 DPL. Total cost was $254,316 for the 1993 group and $168,501 for the 1995 group. Extrapolated to a 1-year period, a significant ( P < 0.05) cost savings of $171,630 would be realized. Cost per patient evaluated was significantly reduced from $285.75 in 1993 to $163.12 in 1995 ( P < 0.05). This represents a 43 per cent reduction in per patient expenditure for evaluating the abdomen. By effectively utilizing ultrasonography in the evaluation of patients with blunt abdominal trauma, a significant cost savings can be realized. This effect results chiefly from an eight-fold reduction in the use of DPL, and a two-fold reduction in the use of CT.

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.

Accuracy of emergency department bedside ultrasonography

OBJECTIVES

To determine which focused ultrasound examinations can be interpreted accurately by emergency physicians who have limited training and experience. To determine whether image quality and/or the operator's level of confidence in the findings correlates with accurate scan interpretation.

METHODS

A prospective sample of consenting adult emergency department patients with the conditions was selected for study. Scans were performed by emergency physicians who had attended a 3-day focused ultrasound examinations instruction course. All scans were videotaped and subsequently reviewed by a radiologist. Accuracy was determined by comparing the emergency physicians scan interpretation with preselected gold standards. Chi-squared tests were employed to determine if the individual performing the scan, the type of scan, patient's body habitus, image quality and/or operator confidence were reliable predictors of accuracy.

RESULTS

Between September 1997 and January 1999, 221 scans were studied. Accuracy varied widely depending on the type of scan performed: aortic scans were 100% accurate whereas renal scans had 68% accuracy. On bivariate analyses, there was little variation in the various operators' levels of proficiency and accuracy of interpretation was not associated with patient body habitus, image quality or operator confidence.

CONCLUSIONS

Neophytes can accurately perform and interpret aortic scans; additional training and/or experience appear to be necessary to achieve proficiency in conducting most of the other scans studied. Inexperienced operators are unable to discern whether their scan interpretations will prove accurate.

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.

Systematic review and meta-analysis of emergency ultrasonography for blunt abdominal trauma

BACKGROUND

How precise and reliable is ultrasonography as a primary tool for injury assessment in blunt abdominal trauma?

METHODS

A systematic review and meta-analysis were conducted of prospective clinical trials of ultrasonography for blunt abdominal trauma. Publications were retrieved by structured searching among databases, review articles and major text books. Authors and experts in the field were contacted for original and unpublished data. For statistical analysis, summary receiver operating characteristic curves (SROCs) were computed using weighted and robust regression models, with Q* denoting the shoulder of the curve. Post-test probabilities were calculated as a function of pooled likelihood ratios (LRs).

RESULTS

Thirty of 123 trials enrolling 9047 patients were eligible for final analysis. With respect to targeting organ lesions, ultrasonography showed a summary Q* value of 0.91 (inverse variance weights, 95 per cent confidence interval (c.i.) 0.76-1.07); negative predictive values ranged from 0.72 to 0.99. A similar SROC slope was calculated for screening for free fluid (Q* = 0.89 (95 per cent c.i. 0.73-1.05)). Ultrasonography detects the presence of organ lesions, but fails to exclude abdominal injuries (random effects negative LR 0.23 (95 per cent c.i. 0.18-0.28)). Given a pretest probability of 50 per cent for blunt abdominal injury, a post-test probability of nearly 25 per cent remains in the case of a negative sonogram.

CONCLUSION

Despite its high specificity, ultrasonography has an unexpectedly low sensitivity for the detection of both free fluid and organ lesions. In clinically suspected abdominal trauma, another assessment (e.g. helical computed tomography) must be performed regardless of the initial ultrasonographic findings.

Emergency department ultrasonography in the evaluation of hypotensive and normotensive children with blunt abdominal trauma

PURPOSE

The aim of this study was to evaluate the accuracy of emergency department (ED) ultrasound scan in identifying which children with blunt torso trauma have intraperitoneal fluid associated with intraabdominal injuries (IAI).

METHODS

The authors conducted a prospective, observational study of children (< 16 years old) with blunt trauma who presented to a level 1 trauma center over a 29-month period and underwent abdominal ultrasound scan while in the ED. Ultrasound examinations were ordered at the discretion of the trauma surgeons or ED physicians caring for the patients, performed by trained sonographers, and interpreted at the time of the ultrasound. Ultrasound examinations were interpreted solely for the presence or absence of intraperitoneal fluid. Hypotension was defined as > or = 1 standard deviation below the age-adjusted mean. Patients underwent follow-up to identify those with intraperitoneal fluid and IAI.

RESULTS

A total of 224 pediatric blunt trauma patients had ultrasound scan performed and were enrolled. Thirty-three patients had IAI with intraperitoneal fluid, and ultrasound scan was positive in 27. The accuracy of abdominal ultrasound for detecting intraperitoneal fluid associated with IAI was sensitivity, 82% (95% confidence interval [CI] 65% to 93%); specificity, 95% (95% CI 91% to 97%); positive predictive value, 73% (95% CI 56% to 86%); and negative predictive value, 97% (95% CI 93% to 99%). In the 13 patients who were hypotensive, ultrasound scan correctly identified intraperitoneal fluid in all 7 patients (sensitivity 100%) with IAI, and hemoperitoneum and was negative in all 6 patients (specificity 100%) who did not have hemoperitoneum. Nine patients had IAI without intraperitoneal fluid, and ultrasound scan result was negative for fluid in all 9.

CONCLUSIONS

ED abdominal ultrasound scan used solely for the detection of intraperitoneal fluid in pediatric blunt trauma patients has a modest accuracy. Ultrasonography has the best test performance in those children who are hypotensive and should be obtained early in the ED evaluation of these patients.

Operative versus nonoperative management of blunt abdominal trauma: Role of ultrasound-measured intraperitoneal fluid levels

This study's objective was to analyze whether the quantity of free intraperitoneal fluid on ultrasonography, alone or in combination with unstable vital signs, is sensitive in determining the need for laparotomy in patients presenting with blunt trauma. Adult patients who presented with blunt abdominal trauma to 2 level I trauma centers were enrolled. Combined intraperitoneal fluid levels (anechoic stripe) of 5 intraperitoneal areas were measured and defined as small (< 1.0 cm), moderate (> 1.0 cm, < 3.0 cm), or large (> 3.0 cm). Unstable vital signs were defined as pulse > 100 bpm or systolic blood pressure < 90 mmHg. Exploratory laparotomy or computed tomography scan confirmed hemoperitoneum. Of 270 patients entered into the study, ultrasound detected free intraperitoneal fluid in 33 patients. Of the 18 patients with a large fluid accumulation, 16 underwent exploratory laparotomy (89% sensitivity), and all 8 patients with unstable vital signs underwent exploratory laparotomy (100% sensitivity). Of the 10 patients with a moderate fluid accumulation, 6 underwent exploratory laparotomy (60% sensitivity), and 4 of the 6 patients with unstable vital signs underwent exploratory laparotomy (67% sensitivity). A large intraperitoneal fluid accumulation on ultrasonography in combination with unstable vital signs, is sensitive for determining the need for exploratory laparotomy in patients presenting with blunt trauma.

Defining the Learning Curve for the Focused Abdominal Sonogram for Trauma (FAST) Examination: Implications for Credentialing

Focused Abdominal Sonogram for Trauma (FAST) examination is being used increasingly for the torso evaluation of injured patients. In a controlled setting using peritoneal dialysis patients as models for injured patients with free fluid we hypothesized that more experienced providers would perform FAST with greater accuracy. Twelve fellow or attending level trauma surgeons, two radiologists, and one ultrasound technician were studied for their ability to detect intraperitoneal fluid (0–1600 cm3) in nine peritoneal dialysis patients with two different volumes of dialysate/patient. FAST experience with injured patients was defined as minimal (<30 patients examinations), moderate (30–100), or extensive (>100). All surgeons had participated in a didactic/practical course before the study. Test results were reported as “+” or “-” by the participant; “+” results were further quantified by volume. The sensitivity of those in the minimal-, moderate-, and extensive-experience to detect <1 L was 45, 87, and 100 per cent, respectively; the accuracy in detecting dialysate volume within 250 cm3 was 38, 63, and 90 per cent, respectively. In this controlled setting the accuracy of FAST particularly in diagnosing smaller volumes, as well as the ability to quantify volume, improves with experience. The learning curve for FAST starts to flatten out at 30 to 100 examinations. Training and credentialing policies should consider these findings to optimize patient care.