Ultrasound evaluation of blunt abdominal trauma: program implementation, initial experience, and learning curve

The role of ultrasound in the assessment of the trauma patient

Ultrasound assessment of the patient with blunt abdominal trauma will enhance diagnostic accuracy and facilitate decision making about the need for urgent surgery. Numerous studies have reported the role of ultrasound in the assessment of the trauma patient. Focused ultrasound has been shown to compare in sensitivity to diagnostic peritoneal lavage and is helpful in assessing the need for a laparotomy. Ultrasound is safe, cheap and portable. The investigation is non-invasive and painless. The trauma ultrasound scan can be completed in under 3 minutes and should be performed during the initial trauma assessment. The technique is not difficult to learn. Advances in technology are likely to make portable ultrasound increasingly appropriate to rural clinical practice. Detection of haemoperitoneum will be more accurate when ultrasound is available in the early care of trauma on a 24 hour basis and, to achieve this, clinicians managing trauma will need to become competent in the application of the focused ultrasound exam.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Focused abdominal sonogram for trauma: the learning curve of nonradiologist clinicians in detecting hemoperitoneum

BACKGROUND

The focused abdominal sonogram for trauma (FAST) has been used by surgeons and emergency physicians (CLIN) to screen reliably for hemoperitoneum after trauma. Despite recommendations for "appropriate training," ranging from 50 to 400 proctored examinations, there are no supporting data.

METHODS

We prospectively examined the initial FAST experience of CLIN in detecting hemoperitoneum by using diagnostic peritoneal lavage, computed tomography, and clinical findings as the diagnostic "gold standard."

RESULTS

241 patients had FAST performed by 12 CLIN (average, 20/CLIN; range, 2-43); 51 patients (21.2%) had hemoperitoneum and 17 patients (7.1%) required laparotomy. Initial experience with FAST by CLIN produced 35 true positives, 180 true negatives, 16 false negatives, and 3 false positives; sensitivity, 68%; specificity, 98%. Initial error rate was 17%, which fell to 5% after 10 examinations (chi2; p < 0.05).

CONCLUSION

Previous recommendations for the number of proctored examinations for individual nonradiologist clinician sonographers to develop competence are excessive.

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

OBJECTIVE

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

SETTING

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

PARTICIPANTS

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

RESULTS

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

CONCLUSION

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

Surgical Residents and Ultrasound Technician Accuracy and Cost-effectiveness of Ultrasound in Trauma

The purpose of this study is 2-fold: 1) to assess the accuracy of the Focused Abdominal Sonogram for Trauma (FAST) as an important evaluative tool for the trauma victim as compared with other objective testing resources (i.e., computerized axial tomography scan); and 2) to analyze the cost-effectiveness of FAST as performed by surgical residents as compared with ultrasound (US) technicians. FAST was performed on 650 trauma victims over a period of 12 months. Testing was completed in a trauma room of the emergency department by an US technician or a trauma surgical resident as determined by the availability of the US technician. Hypotensive patients required two FASTs to be completed for comparison of results. Persistent difficulty interpreting the FAST required the addition of a computerized axial tomography scan to help clarify the results. Statistical analysis was performed using χ2 and analysis of variance. False positive, false negative, and true positive, true negative, along with the accuracy of FAST were calculated as compared with other diagnostic testing. The finding indicated that FAST was both specific (99 per cent) and sensitive (68 per cent) in the sample used. Of the 650 patients receiving FAST, true negative was 95 per cent, true positive was 3 per cent as compared with false negative at 1 per cent, and false positive at 0.5 per cent. US technicians performed 81 per cent of the FASTs with an accuracy of 92 per cent. In comparison, surgical residents had a 92 per cent rate of accuracy in the remaining 19 per cent of the population. The mean accuracy of both was 94 per cent. Furthermore, FAST as performed by resident incurred a single fee of $88 for radiological readings as compared with $274 for an US technician fee plus the radiological reading fee of $88. FAST as performed by surgical residents is more cost-effective than FAST as performed by an US technician.

Preliminary experience with focused abdominal sonography for trauma (FAST) in children: is it useful?

BACKGROUND/PURPOSE

Most pediatric surgeons and pediatric radiologists consider computed tomography (CT) the best radiological test for the evaluation of children with suspected intraabdominal injury. The majority of injured children evaluated with CT will be found to have a normal scan. Focused abdominal sonography for trauma (FAST) has been shown to be a useful screening test in the evaluation of adult patients with suspected intraabdominal injury. Limited data exist regarding the use of FAST in children. Our aim was to evaluate the usefulness of FAST as a screening test in the evaluation of children with suspected intraabdominal injury in an attempt to minimize the number of normal CT scans performed.

METHODS

Hemodynamically stable children evaluated for suspected intraabdominal injury were prospectively screened with FAST. FAST, real-time sonography at four sites, was performed by staff pediatric radiologists. The average duration of the examination was 2 minutes. Positive and negative FAST scan findings were defined prospectively. The result of each FAST was recorded (positive or negative) and then all patients underwent CT as a control. All management decisions were based on CT results.

RESULTS

Forty-six patients were included in the study. FAST identified four children with positive findings (free intraperitoneal fluid), whereas CT showed 13 children with injuries (nine with associated free intraperitoneal fluid and four with only solid organ injury and no associated intraperitoneal fluid). There were nine false-negative and no false-positive FAST scans. The sensitivity of FAST was 0.3 and the specificity was 1.0. Injuries missed by FAST included liver laceration, adrenal hematoma, renal laceration, small bowel injury and splenic laceration.

CONCLUSION

Preliminary results suggest that FAST alone is not a useful screening test in the evaluation of children with suspected intraabdominal injury.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

OBJECTIVE

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

SUMMARY BACKGROUND DATA

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Ultrasound as used in thoracoabdominal trauma

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

Can surgeons evaluate emergency ultrasound scans for blunt abdominal trauma?

OBJECTIVE

To determine whether surgeons and residents with minimal training can evaluate accurately emergency ultrasound (US) examinations compared with radiologists for blunt abdominal trauma.

METHODS

Over 7 months, we conducted a prospective study comparing the evaluation of emergency US for blunt abdominal trauma by surgeons and attending radiologists. US readings from the surgical team and the radiologists were correlated with outcome.

RESULTS

One hundred-twelve patients were included in the study. Ninety-two patients had an US read as negative by the surgical and radiology services with no subsequent injuries identified. Eighteen patients had an US deemed positive by the surgical service and radiologists. Injuries were confirmed in this group by operation or computed tomography. One patient had an US deemed positive by the surgical team and subsequently negative by the radiologist. A diagnostic peritoneal lavage was performed which was negative. Another patient had an US interpreted as negative by the surgical evaluator and positive by the radiologist. Exploratory laparotomy was negative for intraabdominal hemorrhage or organ injury. Overall results reveal an accuracy on US reading of 99% for the surgical team and 99% for the attending radiologists.

CONCLUSION

Surgeons and surgical residents at different levels of training can accurately interpret emergency ultrasound examinations for blunt trauma from the real-time images, at a level comparable to attending radiologists.

Blunt and penetrating trauma--has anything changed?

Management of abdominal trauma has changed significantly in the last decade. The next decade will also see significant change as imaging and minimally invasive surgical techniques evolve and more approaches are examined in well-designed prospective studies.

Ultrasound based key clinical pathway reduces the use of hospital resources for the evaluation of blunt abdominal trauma

BACKGROUND

Evaluating blunt abdominal trauma remains a resource intensive aspect of trauma care. Recently, emergency department ultrasound has been promulgated as a noninvasive diagnostic alternative. Consequently, we hypothesized that an ultrasound based key clinical pathway (KCP) would reduce the number of diagnostic peritoneal lavage (DPL) and computed tomographic (CT) scans required to evaluate blunt abdominal trauma without increased risk to the patient.

METHODS

This study was a prospective analysis of patients evaluated for blunt abdominal trauma during a 3-month period using this KCP compared with a 3-month historical cohort.

RESULTS

Data were collected for 486 KCP patients and were compared with 516 patients in the study cohort. No differences were noted regarding demographics, number of laparotomies, or type of injuries. Using the KCP, DPL was reduced from 17 to 4%, and computed tomography from 56 to 26%. Furthermore, the injury severity score increased from 11.6 to 21.5 for DPL patients and from 4.6 to 8.3 for computed tomography patients. Ultrasound exams were used exclusively in 65% of patients.

CONCLUSIONS

An ultrasound based KCP resulted in significant reductions in the use of invasive DPL and costly CT scanning in the evaluation of blunt abdominal trauma without risk to the patient.