Pelvic Free Fluid in Asymptomatic Pediatric Blunt Abdominal Trauma Patients: A Case Series and Review of the Literature

Updates on the clinical integration of point-of-care ultrasound in pediatric emergency medicine

PURPOSE OF REVIEW

There is expanding evidence for point-of-care ultrasound (POCUS) use in pediatric emergency medicine - this review highlights the benefits and challenges in the clinical integration of high-yield POCUS applications. Specifically, it will delve into POCUS applications during resuscitations, controversies of Focused Assessment with Sonography for Trauma (FAST) in pediatric trauma, POCUS-guided procedures, and examples of clinical pathways where POCUS can expedite definitive care.

RECENT FINDINGS

POCUS can enhance diagnostic accuracy and aid in management of pediatric patients in shock and help identify reversible causes during cardiac arrest. The use of the FAST in pediatric blunt abdominal trauma remains nuanced - its proper use requires an integration with clinical findings and an appreciation of its limitations. POCUS has been shown to enhance safety and efficacy of procedures such as nerve blocks, incision & drainage, and intravenous access. Integrating POCUS into pathways for conditions such as intussusception and testicular torsion expedites downstream care.

SUMMARY

POCUS enhances diagnostic efficiency and management in pediatric patients arriving at the ED with undifferentiated shock, cardiac arrest, or trauma. Additionally, POCUS improves procedural success and safety, and is integral to clinical pathways for expediting definitive care for various pediatric emergencies. Future research should continue to focus on the impact of POCUS on patient outcomes, ensuring user competency, and the expansion of POCUS into diverse settings.

Ultrasonographic Evaluation of Physiologic Free Intraperitoneal Fluid in Healthy Children: A Prospective Observational Study

OBJECTIVES

The detection of intraperitoneal free fluid (FF) is an important finding in the sonographic evaluation of the pediatric abdomen, especially in the context of blunt abdominal trauma. One specific challenge is differentiating physiologic from pathologic FF. The purpose of this study was to determine with ultrasound the prevalence, location, and volume of intraperitoneal FF in healthy pediatric patients and its relation to pubertal status and gender.

METHODS

Healthy children between the ages of 1 and 17 years who presented to the emergency department with non-abdominal complaints were evaluated for physiologic intra-abdominal fluid. Point-of-Care Ultrasound (POCUS) was performed, utilizing the Focused Assessment with Sonography in Trauma (FAST) examination.

RESULTS

A total of 325 pediatric patients were analyzed. Intraperitoneal FF was found in 52 children (16.0%, 95% CI: 12.0-20.0%). The pelvis was the only region where FF was located. The prevalence of FF was nearly equivalent between male and female children (15.4% vs 16.7%, P = .76). There was a higher prevalence of FF identified in the prepubertal subgroup compared to the pubertal group (20.0% vs 11.3%, P = .03). Seventy-seven percent of children with FF had a fluid volume of less than 1 mL.

CONCLUSIONS

Physiologic FF of less than 1 mL within the pelvis is a common finding in the pediatric population. There was no difference in the rate of FF identified by gender, but there was a higher prevalence of FF among prepubertal children.

Development of a Consensus-Based Definition of Focused Assessment With Sonography for Trauma in Children

Importance

The wide variation in the accuracy and reliability of the Focused Assessment With Sonography for Trauma (FAST) and the extended FAST (E-FAST) for children after blunt abdominal trauma reflects user expertise. FAST and E-FAST that are performed by experts tend to be more complete, better quality, and more often clinically valuable.

Objective

To develop definitions of a complete, high-quality, and accurate interpretation for the FAST and E-FAST in children with injury using an expert, consensus-based modified Delphi technique.

Design, Setting, and Participants

This consensus-based qualitative study was conducted between May 1 to June 30, 2021. It used a scoping review and iterative Delphi technique and involved 2 rounds of online surveys and a live webinar to achieve consensus among a 26-member panel. This panel consisted of international experts in pediatric emergency point-of-care ultrasonography.

Main Outcomes and Measures

Definitions of complete, high-quality, and accurate FAST and E-FAST studies for children after injury.

Results

Of the 29 invited pediatric FAST experts, 26 (15 men [58%]) agreed to participate in the panel. All 26 panelists completed the 2 rounds of surveys, and 24 (92%) participated in the live and asynchronous online discussions. Consensus was reached on FAST and E-FAST study definitions, and the panelists rated these 5 anatomic views as important and appropriate for a complete FAST: right upper-quadrant abdominal view, left upper-quadrant abdominal view, suprapubic views (transverse and sagittal), and subxiphoid cardiac view. For E-FAST, the same FAST anatomic views with the addition of the lung or pneumothorax view were deemed appropriate and important. In addition, the panelists rated a total of 32 landmarks as important for assessing completeness. Similarly, the panelists rated 14 statements on quality and 20 statements on accurate interpretation as appropriate.

Conclusions and Relevance

This qualitative study generated definitions for complete FAST and E-FAST studies with high image quality and accurate interpretation in children with injury. These definitions are similar to those in adults with injury and may be used for future education, quality assurance, and research. Future research may focus on interpretation of trace volumes of abdominal free fluid and the use of serial FAST.

Microhematuria as an Indicator of Significant Abdominal Injury

BACKGROUND AND OBJECTIVES

Trauma is one of the leading causes of morbidity and mortality in the pediatric population. In many centers, microhematuria is used as a screening tool for the presence of significant abdominal injury and as an indication for further imaging. Our objective was to evaluate the role of microhematuria by dipstick as an indicator of significant abdominal injury in children.

METHODS

A retrospective review of children aged 0 to 16 years admitted for a motor vehicle accident or a fall from 2007 to 2017 who had urinalyses performed.

RESULTS

The charts of 655 children were reviewed. Microhematuria was found in 100 children, of whom 49 (49%), 28 (28%), and 23 (23%) had small, moderate, and large amounts of hematuria, respectively. Of the children who had microhematuria, 41 underwent a computed tomography scan. Positive findings were recorded in 16 (39%) of these patients. There was a clear association between microhematuria as detected by the urine dipstick and a significant finding on the computed tomography scan (P = 0.002). The sensitivity of microhematuria for significant abdominal pathology on imaging was 66.6% and the specificity was 68.3% (positive predictive value, 39%; negative predictive value, 87.1%). Microhematuria was associated with increased length of stay in the hospital (P < 0.001), surgical interventions (P = 0.036), and admission to the pediatric intensive care unit (P < 0.001).

CONCLUSIONS

The diagnostic role of dipstick urine analysis in the assessment of intra-abdominal injury has low sensitivity and specificity. Nevertheless, it is still a valuable screening tool for the evaluation of the severity of injury.

Reevaluation of FAST Sensitivity in Pediatric Blunt Abdominal Trauma Patients: Should We Redefine the Qualitative Threshold for Significant Hemoperitoneum?

BACKGROUND

The utility of the focused assessment with sonography in trauma (FAST) examination in hemodynamically stable pediatric blunt abdominal trauma (BAT) patients is controversial.We report our 3-year experience with FAST performance to detect greater than physiologic amounts of intraperitoneal fluid after BAT.

METHODS

We performed a retrospective chart review of all FAST examinations performed from July 2015 to June 2018 at a level I pediatric trauma center. The main outcome of interest was the performance of a concerning FAST (cFAST) compared with a computed tomography scan diagnosis for greater than physiologic levels of free fluid (FF) and clinical follow-up. A cFAST was defined by the presence of any FF in the upper abdomen or by a moderate to large amount of FF present in the pelvis. The interobserver reliability of cFASTwas assessed with Cohen κ coefficient. Locations of FF were assessed.

RESULTS

A total of 448 FAST cases were eligible for review. The median age was 11 years with 64% male. Thirty-one FAST examinations (6.9%) were positive for some amount of FF; 18 (4.0%) were cFASTs. In the cFAST group, 11 patients (61%) were hemodynamically stable. The cFAST had a sensitivity of 89% (95% confidence interval [CI], 65%-99%), specificity of 99% (95% CI, 98%-100%), positive predictive value of 89% (95% CI, 67%-97%), and negative predictive value of 99% (95% CI, 98%-100%). The positive and negative likelihood ratios were 191 (95% CI, 47-769) and 0.11 (95% CI, 0.03-0.41). The κ coefficient for cFASTwas 0.72 with 86% agreement. Free fluid on cFAST cases was observed in the pelvis (78%), right upper quadrant (44%), and left upper quadrant (44%).

CONCLUSIONS

In pediatric BAT patients, a cFAST has acceptable sensitivity and remains a highly specific test to rule in greater than physiologic quantities of FF with confidence.

Test characteristics of focused assessment with sonography for trauma (FAST), repeated FAST, and clinical exam in prediction of intra-abdominal injury in children with blunt trauma

PURPOSE

In children with blunt abdominal trauma (BAT), focused assessment of sonography in trauma (FAST) has been reported with low sensitivity, on the whole, in the detection of intra-abdominal injuries (IAI). The aim of the present study was to assess test characteristics of FAST using different strategies including repeated FAST (reFAST), and physical exam findings.

METHODS

This retrospective study evaluated BAT pediatric patients with stable hemodynamics who underwent computed tomography (CT). Demographic data, initial physical examination, and results of FAST, reFAST (if done), and CT imaging were recorded. Different strategies of FAST were cross-tabulated with CT as the gold standard and test characteristics including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were interpreted.

RESULTS

129 patients with a mean age of 8.6 ± 4.7 were studied and 74% were male. Comparing CT-positive and -negative groups, from the demographic and clinical findings, only positive physical exam (tenderness or ecchymosis) was significantly higher in the CT-positive group (59% vs. 17%; p < 0.01). In a multivariate analysis, positive FAST modality and clinical exam remained independent predictors for a positive CT result (likelihood ratios of 34.6 and 6.4, respectively). Out of the different diagnostic strategies for the prediction of IAI, the best overall performance resulted from the FAST-reFAST-tenderness protocol with sensitivity, specificity, PPV, NPV, and accuracy of 87%, 77%, 70%, 91%, and 81%.

CONCLUSION

For children with blunt abdominal trauma, physical examination plus FAST and reFAST as needed, seems to have reasonable sensitivity, specificity, and accuracy in detecting intra-abdominal injuries and may reduce the need for CT scans.

Predictive value of a false-negative focused abdominal sonography for trauma (FAST) result in patients with confirmed traumatic abdominal injury

Objective

To investigate if patients with confirmed traumatic abdominal injury and a false-negative focused abdominal sonography for trauma (FAST) examination have a more favorable prognosis than those with a true-positive FAST.

Methods

This study included 97 consecutive patients with confirmed traumatic abdominal injury (based on computed tomography [CT] and/or surgical findings) who underwent FAST.

Results

FAST was false-negative in 40 patients (41.2%) and true-positive in 57 patients (58.8%). Twenty-two patients (22.7%) had an unfavorable outcome (defined as the need for an interventional radiologic procedure, laparotomy, or death due to abdominal injury). Univariately, a false-negative FAST (odds ratio [OR] 0.24; p = 0.017) and a higher systolic blood pressure (OR, 0.97 per mmHg increase; p = 0.034) were significantly associated with a favorable outcome, whereas contrast extravasation on CT (OR, 7.17; p = 0.001) and shock index classification (OR, 1.89 for each higher class; p = 0.046) were significantly associated with an unfavorable outcome. Multivariately, only contrast extravasation on CT remained significantly associated with an unfavorable outcome (OR, 4.64; p = 0.016). When excluding contrast extravasation on CT from multivariate analysis, only a false-negative FAST result was predictive of a favorable outcome (OR, 0.28; p = 0.038).

Conclusion

Trauma patients with confirmed abdominal injury and a false-negative FAST have a better outcome than those with a positive FAST. FAST may be valuable for risk stratification and prognostication in patients with a high suspicion of abdominal injury when CT has not been performed yet or when CT is not available.