Clinical Predictors of Injuries Not Identified by Focused Abdominal Sonogram for Trauma (FAST) Examinations

Accuracy of FAST in detecting intraabdominal bleeding in major trauma with pelvic and/or acetabular fractures: a retrospective cohort study

PURPOSE

The Focused Assessment with Sonography for Trauma (FAST) is a tool to rapidly detect intraabdominal and intrapericardial fluid with point-of-care ultrasound. Previous studies have questioned the role of FAST in patients with pelvic fractures. The aim of the present study was to assess the accuracy of FAST to detect clinically significant intraabdominal hemorrhage in patients with pelvic fractures.

METHODS

We included all consecutive patients with pelvic and/or acetabular fractures treated our Level 1 trauma center from 2009-2020. We registered patient and fracture characteristics, FAST investigations and CT descriptions, explorative laparotomy findings, and transfusion needs. We compared FAST to CT and laparotomy findings, and calculated true positive and negative findings, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV).

RESULTS

We included 389 patients. FAST had a sensitivity of 75%, a specificity of 98%, a PPV of 84%, and a NPV of 96% for clinically significant intraabdominal bleeding. Patients with retroperitoneal hematomas were at increased risk for laparotomy both because of True-negative FAST and False-positive FAST.

CONCLUSION

FAST is accurate to identify clinically significant intraabdominal blood in patients with severe pelvic fractures and should be a standard asset in these patients. Retroperitoneal hematomas challenge the FAST interpretation and thus the decision making when applying FAST in patients with pelvic fractures.

Consequencies of therapeutic decision-making based on FAST results in trauma patients with pelvic fracture

INTRODUCTION

FAST is essential to decide whether trauma patients need laparotomy, but it has a notable decrease in accuracy in patients with pelvic fracture. Our objective is to analyze the consequences of therapeutic decision-making based on the FAST results in trauma patients with pelvic fracture.

METHODS

Descriptive study that includes trauma patients older than 16 with a pelvic fracture admitted to the critical care area or who died. The FAST result was compared with a true positive or negative value according to the results of laparotomy or abdominal CT. We recorded diagnosis and treatment of each injury and resolution of the case, detailing the cause of death, among all variables.

RESULTS

Over the 13-year period, we included 263 trauma patients with pelvic fracture, with a mean ISS of 31 and mortality of 19%. FAST had a sensitivity of 65.2%, specificity of 69%, false negative rate of 34.8% and false positive rate of 30.9%. Hemodynamically unstable patients died twice as many stable patients (27% vs 14%, P < .05). Patients with positive FAST died more than negative FAST (43% vs 26%); and 4 out of 10 hemodynamically unstable patients who underwent non-therapeutic laparotomy after presenting a false positive FAST died from hypovolemic shock. The mortality rate fell from 60% to 20% when preperitoneal packing was performed before angio-embolization of the pelvis.

CONCLUSION

FAST has low accuracy in polytraumatized patients with pelvic fracture. Patients with false positive FAST have higher mortality, which can be reduced notably by applying preperitoneal packing.

Trust the FAST: Confirmation that the FAST examination is highly specific for intra-abdominal hemorrhage in over 1,200 patients with pelvic fractures

BACKGROUND

Use of the focused assessment with sonography for trauma (FAST) examination in patients with pelvic fractures has been reported as unreliable. We hypothesized that FAST is a reliable method for detecting clinically significant intra-abdominal hemorrhage in patients with pelvic fractures.

METHODS

All patients with pelvic fractures over a 10-year period were reviewed at a Level I trauma center. The predictive ability of FAST was assessed by calculating the sensitivity, specificity, positive predictive value and negative predictive value against the criterion standard of either computed tomography (CT) or laparotomy findings. The FAST examination was considered "false negative" if findings at laparotomy indicated traumatic intra-abdominal hemorrhage. Likewise, the FAST examination was considered "false positive" if either CT or findings at laparotomy indicated no intra-abdominal hemorrhage. Hemodynamic instability scores were calculated for all patients.

RESULTS

There were 1,456 patients with pelvic fractures and an initial FAST reviewed; 1,219 (83.7%) underwent FAST and either CT or operative exploration. Median age was 43 years (interquartile range, 26-56 years) and mean Injury Severity Score was 18.5 ± 12.3. The sensitivity and specificity for FAST in this group of patients with pelvic fracture was 85.4% and 98.1%, respectively. The positive predictive value and negative predictive value were 78.4% and 98.8%, respectively. Of 21 patients with a false-positive FAST, 15 (71.4%) were confirmed with a negative CT scan, and 6 (28.6%) underwent laparotomy without findings of intra-abdominal hemorrhage. Of 13 patients with a false-negative FAST, all were identified with positive findings at the time of laparotomy. The specificity of the FAST examination remained high regardless of hemodynamic instability score grade.

CONCLUSION

The false positive rate of FAST examination for intra-abdominal hemorrhage is 1.1%. These data suggest that a positive FAST in this clinical scenario should be considered to represent intra-abdominal fluid. This series contradicts prior reports that FAST is unreliable in patients with pelvic fracture.

LEVEL OF EVIDENCE

Diagnostic, level III.

Consequencies of therapeutic decision-making based on FAST results in trauma patients with pelvic fracture

INTRODUCTION

FAST is essential to decide if trauma patients need laparotomy, but has a notably decrease in accuracy in patients with pelvic fracture. Our objective is to analyze the consequences of therapeutic decision-making based on the FAST results in trauma patients with pelvic fracture.

METHODS

Descriptive study that includes trauma patients older than 16 with a pelvic fracture admitted to the critical care area or who were fallecimiento. FAST result was compared with a true positive or negative value according to the results of laparotomy or abdominal CT. We recorded diagnosis and treatment of each injury and resolution of the case, detailing the cause of death, among all variables.

RESULTS

Over the 13-year period, we included 263 trauma patients with pelvic fracture, with a mean ISS of 31 and mortality of 19%. FAST had a sensitivity of 65.2%, specificity of 69%, false negative rate of 34.8% and false positive rate of 30.9%. Hemodynamically unstable patients died twice as many stable patients (27% vs. 14%, p <0.05). Patients with positive FAST died more than negative FAST (43% vs. 26%); and 4 of 10 hemodynamically unstable patients who underwent non therapeutic laparotomy after presenting a false positive FAST died from hypovolemic shock. The mortality rate fell from 60% to 20% when preperitoneal packing was performed before angio-embolization of the pelvis.

CONCLUSION

FAST has low accuracy in polytraumatized patients with pelvic fracture. Patients with false positive FAST have higher mortality, which can be reduce notably applying a preperitoneal packing.

Efficacy of new scoring system for diagnosis of abdominal injury after blunt abdominal trauma in patients referred to emergency department

PURPOSE

The blunt abdominal trauma (BAT) is a common emergency and is significantly associated with morbidity and mortality. Our study was conducted to achieve the goal that a new scoring system could be used for the BAT patients.

METHODS

The statistical population of this study was 1000 patients with BAT referred to emergency department of Imam Hossein Hospital, Tehran, Iran. Sampling was carried out in a convenience non-random manner and continued to reach the required sample size. All the patients with BAT due to road traffic accidents, falls, and other direct blunt traumas such as punctures and kickbacks were included in the study. Exclusion criteria were after 3 months of pregnancy, under the age of 18, warfarin taking, no reliable medical history providing and penetrating trauma. The study questionnaire was based on BAT scoring system. The data were analyzed by SPSS V20 software. The receiver operating characteristic curve was used to analyze the effectiveness of the new scoring system in predicting the BAT patients' outcome.

RESULTS

The mean age of the patients (n = 1000) was (35.79 ± 13.09) years. The mean score of patients was (6.29 ± 5.80). Based on this scoring system, the patients were divided into three categories. The first group was patients at low risk with score of less than 8, the second group was patients at moderate risk with score of 8-12 and the third group was patients at high risk with score of 12-24. The score of 661 (66.1%) patients were low, 109 (10.9%) were moderate and 230 (23%) had a high score. The association between hip fracture and abdominal tenderness with abdominal injury was significant (p < 0.001). Cronbach's alpha was 0.76 showing the reliability of this questionnaire to predict the future of patients.

CONCLUSIONS

The study tool has a sensitivity to predict the BAT patients' outcome, and has a proper specificity that can be used to reduce the use of harmful modalities such as computed tomography scan.

Predictors of False-Negative Focused Assessment With Sonography for Trauma Examination in Pediatric Blunt Abdominal Trauma

OBJECTIVES

This study investigated associations between patient and injury characteristics and false-negative (FN) focused assessment with sonography for trauma (FAST) in pediatric blunt abdominal trauma (BAT). We also evaluated the effects of FN FAST on in-hospital mortality and length of stay (LOS) variables.

METHODS

This retrospective cohort studied children younger than 18 years between January 1, 2002, and December 31, 2013, with BAT, documented FAST, and pathologic fluid on computed tomography, surgery, or autopsy. Multivariable and bivariate analyses were used to assess associations between FN FAST and patient injury characteristics, mortality, and hospital LOS.

RESULTS

A total of 141 pediatric BAT patients with pathologic free fluid were included. There were no patient or injury characteristics, which conferred increased odds of an FN FAST. Splenic and bladder injury were negatively associated with FN FAST odds ratio of 0.4 (95% confidence interval [CI], 0.2-0.8) and 0.1 (95% CI, 0-0.8). Abbreviated Injury Scale score of 4 or greater to the abdomen and extremity was negatively associated with FN FAST odds ratio of 0.1 (95% CI, 0-0.3) and 0.3 (95% CI, 0.1-0.9). There was no association between FN FAST and mortality. Patients with an FN FAST had increased hospital LOS after controlling for sex, age, and Injury Severity Score.

CONCLUSIONS

Clinicians need to be cautious applying a single initial FAST to patients with minor abdominal trauma or with suspected injuries to organs other than the spleen or bladder. Formalized studies to develop risk stratification tools could allow clinicians to integrate FAST into the pediatric patient population in the safest manner possible.

Delayed hemopericardium due to non-penetrating chest trauma: a report of new case and literature review

To our knowledge, only 15 cases of delayed traumatic hemopericardium resulting from non-penetrating chest trauma have been reported. We present the case of a 63-year-old man with delayed hemopericardium, 2 months after striking the anterior chest on a mailbox when he fell down three steps during a postal delivery. Our case and review of the previously reported cases suggest that some cases might show quite slow progression of blood accumulation. Therefore, careful observation of patients who have experienced blunt trauma of the anterior chest is necessary.

Imaging Genitourinary Trauma

Contrast-enhanced multidetector computed tomography (MDCT) has become a critical tool in the evaluation of the trauma patient. MDCT can quickly and accurately assess trauma patients for renal, ureteral, and bladder injuries. Moreover, CT guides clinical management triaging patients to those requiring discharge, observation, angioembolization, and surgery. Recognition of urinary tract trauma on initial scan acquisition should prompt delayed excretory phase imaging to identify urine leaks. Urethral and testicular trauma are imaged with retrograde urethrography and sonography, respectively.

Diagnostic accuracy of emergency-performed focused assessment with sonography for trauma (FAST) in blunt abdominal trauma

Introduction

Intra-abdominal hemorrhage due to blunt abdominal trauma is a major cause of trauma-related mortality. Therefore, any action taken for facilitating the diagnosis of intra-abdominal hemorrhage could save the lives of patients more effectively. The aim of this study was to determine the accuracy of focused assessment with sonography for trauma (FAST) performed by emergency physicians.

Methods

In this cross-sectional study from February 2011 to January 2012 at 7^th Tir Hospital in Tehran (Iran), 120 patients with abdominal blunt trauma were chosen and evaluated for abdominal fluid. FAST sonography was performed for all the subjects by emergency residents and radiologists while they were blind to the other tests. Abdominal CTs, which is the gold standard, were done for all of the cases. SPSS 20.0 was used to analyze the results.

Results

During the study, 120 patients with abdominal blunt trauma were evaluated; the mean age of the patients was 33.0 ± 16.6 and the gender ratio was 3/1 (M/F). The results of FAST sonography by emergency physicians showed free fluid in the abdomen or pelvic spaces in 33 patients (27.5%), but this was not observed by the results of CT scans of six patients; sensitivity and specificity were 93.1 and 93.4%, respectively. As for tests performed by radiology residents, sensitivity was a bit higher (96.5%) with lower specificity (92.3%).

Conclusion

The results suggested that emergency physicians can use ultrasonography as a safe and reliable method in evaluating blunt abdominal trauma.

Severity and treatment of "occult" intra-abdominal injuries in blunt trauma victims

BACKGROUND

to assess the severity and treatment of "occult" intra-abdominal injuries in blunt trauma victims.

METHOD

Retrospective analysis of charts and trauma register data of adult blunt trauma victims, admitted without abdominal pain or alterations in the abdominal physical examination, but were subsequently diagnosed with intra-abdominal injuries, in a period of 2 years. The severity was stratified according to RTS, AIS, OIS and ISS. The specific treatment for abdominal injuries and the complications related to them were assessed.

RESULTS

Intra-abdominal injuries were diagnosed in 220 (3.8%) out of the 5785 blunt trauma victims and 76 (34.5%) met the inclusion criteria. The RTS and ISS median (lower quartile, upper quartile) were 7.84 (6.05, 7.84) and 25 (16, 34). Sixty seven percent had a GCS≥13 on admission. Injuries were identified in the spleen (34), liver (33), kidneys (9), intestines (4), diaphragm (3), bladder (3) and iliac vessels (1). Abdominal injuries scored AIS≥3 in 67% of patients. Twenty-one patients (28%) underwent laparotomy, 5 of which were nontherapeutic. The surgical procedures performed were splenectomy (8), suturing of the diaphragm (3), intestines (3), bladder (2), kidneys (1), enterectomy/anastomosis (1), ligation of the common iliac vein (1), and revascularization of the common iliac artery (1). Angiography and embolization of liver and/or spleen injuries were performed in 3 cases. Three patients developed abdominal complications, all of which were operatively treated. There were no deaths directly related to the abdominal injuries.

CONCLUSION

Severe "occult" intra-abdominal injuries, requiring specific treatment, may be present in adult blunt trauma patients.

Predictors of abdominal injuries in blunt trauma

OBJECTIVE

To identify predictors of abdominal injuries in victims of blunt trauma.

METHOD

retrospective analysis of trauma protocols (collected prospectively) of adult victims of blunt trauma in a period of 15 months. Variables were compared between patients with abdominal injuries (AIS>0) detected by computed tomography or/and laparotomy (group I) and others (AIS=0, group II). Student's t, Fisher and qui-square tests were used for statistical analysis, considering p<0.05 as significant.

RESULTS

A total of 3783 cases were included, with a mean age of 39.1 ± 17.7 years (14-99), 76.1% being male. Abdominal injuries were detected in 130 patients (3.4%). Patients sustaining abdominal injuries had significantly lower mean age (35.4 + 15.4 vs. 39.2 + 17.7), lower mean systolic blood pressure on admission (114.7 + 32.4 mmHg vs. 129.1 + 21.7 mmHg), lower mean Glasgow coma scale (12.9 + 3.9 vs. 14.3 + 2.0), as well as higher head AIS (0.95 + 1.5 vs. 0.67 + 1.1), higher thorax AIS (1.10 + 1.5 vs. 0.11 + 0.6) and higher extremities AIS (1.70 ± 1.8 vs. 1.03 ± 1.2). Patients sustaining abdominal injuries also presented higher frequency of severe injuries (AIS>3) in head (18.5% vs. 7.9%), thorax (29.2% vs. 2.4%) and extremities (40.0% vs. 13.7%). The highest odds ratios for the diagnosis of abdominal injuries were associated flail chest (21.8) and pelvic fractures (21.0).

CONCLUSION

Abdominal injuries were more frequently observed in patients with hemodynamic instability, changes in Glasgow coma scale and severe lesions to the head, chest and extremities.

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

STUDY OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Beyond focused assessment with sonography for trauma: ultrasound creep in the trauma resuscitation area and beyond

PURPOSE OF REVIEW

The use of ultrasound for the management of the injured patient has expanded dramatically in the last decade. The focused assessment with sonography for trauma (FAST) has become one of the fundamental skills incorporated into the initial evaluation of the trauma patient. However, there are significant limitations of this diagnostic modality as initially described. Novel ultrasound examinations of the injured patient, although useful, must also be considered carefully.

RECENT FINDINGS

Increasing evidence supports the high specificity of FAST for detecting a pericardial effusion and intra-abdominal free fluid (hemorrhage) in the patient with blunt injury. On the other hand, a so-called negative FAST result still requires further diagnostic work up given its low sensitivity. Similarly, the role of FAST in penetrating abdominal trauma appears to be limited because of lower sensitivity for visceral injury compared to other modalities. Extended FAST (EFAST), that adds a focused thoracic examination, has high accuracy for the detection of pneumothorax comparable to computed tomographic scan, the significance of which is not currently known. Finally, the utility of intensivist-performed ultrasound in the ICU is expanding to limited hemodynamic assessment and facilitation of central venous catheter placement.

SUMMARY

The indications for FAST and additional ultrasound studies in the injured patient continue to evolve. Application of sound clinical evidence will avoid unsubstantiated indications for ultrasound to creep into our clinical practice.

Abdominal trauma: from operative to nonoperative management

The nonoperative care of intraabdominal trauma in the polytraumatised patient greatly depends on imaging techniques. The haemodynamically unstable patient should undergo expedient sonography to rule out abdominal haemorrhage. The use of computer tomography (CT) in this difficult patient group is also currently evaluated, however it takes specific amendments to the protocol and institution. In the hemodynamically stable patient however, computer tomography is the modality of choice to evaluate the injured abdomen. Nonoperative treatment can be successful in up to 80% of selected cases. Adjuncts to nonoperative care include embolisation of the spleen and liver in cases of arterial bleeding, and endoscopic retrograde cholangio pancreaticography (ERCP) and stenting for injuries to the biliary tree.