Point-of-Care Ultrasonography for the Diagnosis of Pediatric Soft Tissue Infection

Utilization of Point-of-Care Ultrasound as an Imaging Modality in the Emergency Department: A Systematic Review and Meta-Analysis

Point-of-care ultrasound (POCUS) is an imaging modality that has become a fundamental part of clinical care provided in the emergency department (ED). The applications of this tool in the ED have ranged from resuscitation, diagnosis, and therapeutic to procedure guidance. This review aims to summarize the evidence on the use of POCUS for diagnosis and procedure guidance. To achieve this, CrossRef, PubMed, Cochrane Library, Web of Science, and Google Scholar databases were extensively searched for studies published between January 2000 and November 2023. Additionally, the risk of bias assessment was performed using the Quality Assessment of Diagnostic Accuracy Studies 2 (for studies on the diagnostic role of POCUS) and Cochrane Risk of Bias tool (for studies on the use of POCUS for procedure guidance). Furthermore, diagnostic accuracy outcomes were pooled using STATA 16 software (StatCorp., College Station, TX, USA), while outcomes related to procedure guidance were pooled using the Review Manager software. The study included 81 articles (74 evaluating the diagnostic application of POCUS and seven evaluating the use of POCUS in guiding clinical procedures). In our findings sensitivities and specificities for various conditions were as follows: appendicitis, 65% and 89%; hydronephrosis, 82% and 74%; small bowel obstruction, 93% and 82%; cholecystitis, 75% and 96%; retinal detachment, 94% and 91%; abscess, 95% and 85%; foreign bodies, 67% and 97%; clavicle fractures, 93% and 94%; distal forearm fractures, 97% and 94%; metacarpal fractures, 94% and 92%; skull fractures, 91% and 97%; and pleural effusion, 91% and 97%. A subgroup analysis of data from 11 studies also showed that the two-point POCUS has a sensitivity and specificity of 89% and 96%, while the three-point POCUS is 87% sensitive and 92% specific in the diagnosis of deep vein thrombosis. In addition, the analyses showed that ultrasound guidance significantly increases the overall success rate of peripheral venous access (p = 0.02) and significantly reduces the number of skin punctures (p = 0.01) compared to conventional methods. In conclusion, POCUS can be used in the ED to diagnose a wide range of clinical conditions accurately. Furthermore, it can be used to guide peripheral venous access and central venous catheter insertion.

Guidance for clinical practice using emergency and point-of-care ultrasonography

Owing to the miniaturization of diagnostic ultrasound scanners and their spread of their bedside use, ultrasonography has been actively utilized in emergency situations. Ultrasonography performed by medical personnel with focused approaches at the bedside for clinical decision-making and improving the quality of invasive procedures is now called point-of-care ultrasonography (POCUS). The concept of POCUS has spread worldwide; however, in Japan, formal clinical guidance concerning POCUS is lacking, except for the application of focused assessment with sonography for trauma (FAST) and ultrasound-guided central venous cannulation. The Committee for the Promotion of POCUS in the Japanese Association for Acute Medicine (JAAM) has often discussed improving the quality of acute care using POCUS, and the "Clinical Guidance for Emergency and Point-of-Care Ultrasonography" was finally established with the endorsement of JAAM. The background, targets for acute care physicians, rationale based on published articles, and integrated application were mentioned in this guidance. The core points include the fundamental principles of ultrasound, airway, chest, cardiac, abdominal, and deep venous ultrasound, ultrasound-guided procedures, and the usage of ultrasound based on symptoms. Additional points, which are currently being considered as potential core points in the future, have also been widely mentioned. This guidance describes the overview and future direction of ultrasonography for acute care physicians and can be utilized for emergency ultrasound education. We hope this guidance will contribute to the effective use of ultrasonography in acute care settings in Japan.

To Drain or not to Drain? Point-of-care Ultrasound to Investigate an Axillary Mass: Case Report

Introduction: Point-of-care ultrasound (POCUS) has great sensitivity in the diagnosis of abscesses and swollen lymph nodes. Many studies outline the characteristics that distinguish abscesses from lymph nodes on POCUS. Case Report: We present a case from the emergency department in which a patient presented with a potential abscess but was found to have a malignant lymph node on imaging. Conclusion: Point-of-care ultrasound can be used to differentiate an abscess from a swollen lymph node. Abscesses are generally anechoic or hypoechoic with septae, sediment or gas contents, and they lack internal vascularity. Benign lymph nodes are echogenic with hypoechoic cortex with hilar vascularity.

Point-of-Care Ultrasound for the Evaluation of Neck Masses in the Pediatric Emergency Department: A Case Series

ABSTRACT

Point-of-care ultrasound can be an effective tool for pediatric emergency medicine providers in the evaluation of soft tissue lesions. We present a series of 4 pediatric patients with neck lesions in whom point-of-care ultrasound identified the type of lesion, guided decision-making on the need for computed tomography imaging, and led to definitive management.

Number Needed to Scan: Evidence-Based Point-of-Care Ultrasound (POCUS)

Interest and enthusiasm, regarding the use of point-of-care ultrasound (POCUS), continues to grow among clinicians in multiple medical specialties. Ultrasound machines technology has advanced to allow for smaller, even handheld machines. Integration of automated imaging technology has made these machines more user-friendly. However, one of the concerns with the widespread availability of POCUS is the overuse and misuse of this technology. In order to maximize the clinical impact of POCUS, this manuscript seeks to discuss a novel concept called the “Number needed to scan” (NNS). The NNS is an expression of the number of POCUS examinations needed to be performed to attain a benefit to the patient or to prevent an adverse outcome of a procedure. NNS serves a dual purpose: it can help clinicians understand the magnitude of clinical impact when they apply POCUS, and it can help clinicians explain this magnitude in layman terms to their patients. In this manuscript, we have focused our NNS calculations on landmark articles in three major categories: change in management; safety and accuracy; and catching a missed diagnosis. As clinicians seek to be good stewards of POCUS, NNS should be a concept used to consider which patients will be most likely to benefit from a clinician performed ultrasound.

Subcutaneous abscess caused by Streptococcus pneumoniae serotype 28F in an infant: a case report

Background

Invasive pneumococcal disease (IPD) is defined by the detection of Streptococcus pneumoniae on culture from samples obtained from a normally sterile site. Pneumococcal conjugate vaccines (PCV) have been developed for the prevention of IPD that is caused by highly virulent serotypes. Despite the effective reduction of IPD caused by vaccine serotypes after the introduction of PCV, there has been a rapid increase in the incidence of IPD caused by non-vaccine serotypes, and serotype replacement has become a global issue.

Case presentation

We report a previously healthy 4-month-old girl presenting with a large subcutaneous abscess caused by S. pneumoniae, identified as non-vaccine serotype 28F. The patient had received routine vaccination, including PCV vaccination. After the incision and drainage of the subcutaneous abscess, the patient was treated with antibiotics. She was discharged on Day 7 of hospitalization without any residual sequelae.

Conclusions

Subcutaneous abscess is a common pediatric skin and soft tissue infection, whereas pneumococcal subcutaneous abscesses are quite rare. As the pneumococcal serotype 28F caused a subcutaneous abscess, this serotype possibly has a high virulence. The incidence of IPD caused by non-vaccine serotypes, such as 28F, is expected to increase in the future. The consolidation of international data on pneumococcal serotypes is important for the development of novel PCV.

Abscess Management: An Evidence-Based Review for Emergency Medicine Clinicians

BACKGROUND

Abscesses are commonly evaluated and managed in the emergency department. Recent research has evaluated the use of ultrasonography, packing, incision and drainage (I&D), and antibiotics. There are evidence-based nuances to the management of specific types of abscesses, such as Bartholin, breast, dental, hidradenitis suppurativa, peritonsillar, and pilonidal abscesses.

OBJECTIVE

This review provides emergency medicine clinicians with a summary of the current literature regarding abscess management in the emergency department.

DISCUSSION

Ultrasound is valuable in diagnosing abscesses that are not clinically evident and in guiding I&D procedures. Although I&D is traditionally followed by packing, this practice may be unnecessary for small abscesses. Antibiotics, needle aspiration, and loop drainage are suitable alternatives to I&D of abscesses with certain characteristics. Oral antibiotics can improve outcomes after I&D, although this improvement must be weighed against potential risks. Many strategies are useful in managing Bartholin abscesses, with the Word catheter proving consistently effective. Needle aspiration is the recommended first-line therapy for small breast abscesses. Dental abscesses are often diagnosed with clinical examination alone, but ultrasound may be a useful adjunct. Acute abscess formation caused by hidradenitis suppurativa should be managed surgically by excision when possible, because I&D has a high rate of abscess recurrence. Peritonsillar abscesses can be diagnosed with either intraoral or transcervical ultrasound if clinical examination is inconclusive. Needle aspiration and I&D are both suitable for the management of peritonsillar abscesses. Pilonidal abscesses have traditionally been managed with I&D, but needle aspiration with antibiotics may be a suitable alternative.

CONCLUSIONS

This review evaluates the recent literature surrounding abscess management for emergency medicine clinicians.

Interpretation Accuracy and Interrater Agreement of Pediatric Skin and Soft Tissue Point-of-Care Ultrasound Images among Residents and Faculty

BACKGROUND

Point-of-care ultrasound (POCUS) is commonly used to facilitate care in the emergency department. Acquired images are often reviewed by local experts for educational and quality assurance purposes. However, no published study has examined the accuracy and reliability of POCUS image interpretation by multiple reviewers.

OBJECTIVES

We studied the accuracy and interrater agreement among expert and trainee reviewers of prerecorded pediatric skin and soft tissue (SST) POCUS images.

METHODS

POCUS faculty and emergency medicine (EM) residents blindly reviewed deidentified pediatric SST POCUS images and indicated whether a drainable fluid collection was present, absent, or indeterminate. This was then compared with the gold standard based on discharge diagnoses and telephone follow-up. Images rated as indeterminate were excluded from the initial analysis. Sensitivity analysis assuming indeterminate answers were inaccurate was subsequently conducted.

RESULTS

In phase 1, 6 pediatric EM POCUS directors reviewed 168 images. The overall accuracy was 79.7% (range 66.1-86.0%). The mean Cohen's kappa was 0.58 (range 0.24-0.84). Sensitivity analysis yielded an overall accuracy of 71.3% (range 56.5-76.9%) and a Cohen's kappa of 0.43 (range 0.20-0.59). In phase 2, 6 general EM POCUS faculty and 20 EM residents reviewed 120 images. The overall accuracy among residents was 72.2% (range 51.4-84.7%) and among faculty was 83.6% (range 77.9-88.8%). Sensitivity analysis yielded an overall resident accuracy of 63.0% (range 49.5-80.7) and an overall faculty accuracy of 73.9% (range 67.0-79.8%). Fleiss' kappa was 0.322 for residents and 0.461 for faculty.

CONCLUSIONS

We found moderate accuracy and fair to good interrater agreement among POCUS faculty and EM residents reviewing pediatric SST POCUS images.

General Pediatric Clinical Applications of POCUS: Part 1

The use of point-of-care ultrasound (POCUS) performed by non-radiologists has become more widespread and is entering new arenas of clinical care. Children in particular are prime candidates for ultrasound, as they are both usually thinner than adults and are particularly at risk from the harmful effects of ionizing radiation. In this two-part article, we propose 10 uses of POCUS that pediatricians can apply to their practice in both inpatient and outpatient settings. [Pediatr Ann. 2020;49(3):e147-e152.].

Point-of-Care Ultrasound for the Pediatric Hospitalist's Practice

Point-of-care ultrasound (POCUS) has the potential to provide real-time valuable information that could alter diagnosis, treatment, and management practices in pediatric hospital medicine. We review the existing pediatric POCUS literature to identify potential clinical applications within the scope of pediatric hospital medicine. Diagnostic point-of-care applications most relevant to the pediatric hospitalist include lung ultrasound for pneumothorax, pleural effusion, pneumonia, and bronchiolitis; cardiac ultrasound for global cardiac function and hydration status; renal or bladder ultrasound for nephrolithiasis, hydronephrosis, and bladder volumes; soft tissue ultrasound for differentiating cellulitis from abscess; and procedural-guidance applications, including line placement, lumbar puncture, and abscess incision and drainage. We discuss POCUS applications with reviews of major pathologic findings, research gaps, the integration of POCUS into practice, and barriers to implementation.

Effect of Initial Bedside Ultrasonography on Emergency Department Skin and Soft Tissue Infection Management

STUDY OBJECTIVE

We examine the utility of emergency department (ED) ultrasonography in treatment of skin and soft tissue infections.

METHODS

We enrolled ED patients with skin and soft tissue infections and surveyed clinicians in regard to their pre-ultrasonography certainty about the presence or absence of an abscess, their planned management, post-ultrasonography findings, and actual management. We determined sensitivity and specificity of ultrasonography and clinical evaluation, and assessed appropriateness of management changes based on initial clinical assessment and outcomes through 1-week follow-up.

RESULTS

Among 1,216 patients, clinicians were uncertain of abscess presence in 105 cases (8.6%) and certain for 1,111 cases (91.4%). Based on surgical exploration and follow-up through 1 week, sensitivity and specificity for abscess detection by clinical evaluation were 90.3% and 97.7%, and by ultrasonography were 94.0% and 94.1%, respectively. Among 1,111 cases for which the clinician was certain, sensitivity and specificity of clinical evaluation were 96.6% and 97.3% compared with ultrasonographic evaluation sensitivity and specificity of 95.7% and 96.2%, respectively. Of 105 uncertain cases, sensitivity and specificity of ultrasonography were 68.5% and 80.4%. Ultrasonography changed management in 13 of 1,111 certain cases (1.2%), appropriately in 10 of 13 (76.9%) and inappropriately in 3 of 13 (23.1%). Of 105 uncertain cases, ultrasonography changed management in 25 (23.8%), appropriately in 21 of 25 (84.0%) and inappropriately in 4 of 25 (16.0%).

CONCLUSION

Ultrasonography rarely changed management when clinicians were certain about the presence or absence of an abscess. When they were uncertain, ultrasonography changed drainage decisions in approximately one quarter of cases, of which most (84%) were appropriate.

Common Community-acquired Bacterial Skin and Soft-tissue Infections in Children: an Intersociety Consensus on Impetigo, Abscess, and Cellulitis Treatment

PURPOSE

The main objective of this article was to offer practical suggestions, given the existing evidence, for identifying and managing bacterial impetigo, abscess, and cellulitis in ambulatory and hospital settings.

METHODS

Five Italian pediatric societies appointed a core working group. In selected conditions, specially trained personnel evaluated quality assessment of treatment strategies according to the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. Only randomized controlled trials (RCTs) and observational studies were included for quality assessment according to the GRADE methodology. MEDLINE, Ovid MEDLINE, EMBASE, and Cochrane Library databases were searched with a strategy combining MeSH and free text terms.

FINDINGS

The literature review included 364 articles focusing on impetigo, skin abscess, and cellulitis/orbital cellulitis. The articles included for quality assessment according to the GRADE methodology for impetigo comprised 5 RCTs and 1 observational study; for skin abscess, 10 RCTs and 3 observational studies were included; for cellulitis and erysipelas, 5 RCTs and 5 observational studies were included; and for orbital cellulitis, 8 observational studies were included. Recommendations were formulated according to 4 grades of strength for each specific topic (impetigo, skin abscesses, cellulitis, and orbital cellulitis). Where controversies arose and expert opinion was considered fundamental due to lack of evidence, agreement according to Delphi consensus recommendations was included.

IMPLICATIONS

Based on a literature review and on local epidemiology, this article offers practical suggestions for use in both ambulatory and hospital settings for managing the most common bacterial SSTIs.

Point-of-Care Ultrasound to Diagnose Pyomyositis in a Child

We report a case of a patient presenting with fever, right lower leg swelling, and pain who was found to have a fluid collection between muscle planes noted on point-of-care ultrasound. Point-of-care ultrasound raised the clinician's concern for deep musculoskeletal infection, leading to prompt initiation of antibiotics and magnetic resonance imaging.

Recent Advances in Technology and Its Applications to Pediatric Emergency Care

Advances in technology are continuously transforming medical care, including pediatric emergency medicine. The increasing adoption of point-of-care ultrasound examination can improve timely diagnoses without radiation and aids the performance of common procedures. The recent dramatic increase in electronic health record adoption offers an opportunity for enhanced clinical decision-making support. Simulation training and advances in technologies can provide continued proficiency training despite decreasing opportunities for pediatric procedures and cardiorespiratory resuscitation performance. This article reviews these and other recent advances in technology that have had the greatest impact on the current practice of pediatric emergency medicine.

Comparison of Ultrasound Guidance vs. Clinical Assessment Alone for Management of Pediatric Skin and Soft Tissue Infections

BACKGROUND

Point-of-care ultrasound (POCUS) can potentially help distinguish cellulitis from abscess, which can appear very similar on physical examination but necessitate different treatment approaches.

OBJECTIVE

To compare POCUS guidance vs. clinical assessment alone on the management of pediatric skin and soft tissue infections (SSTI) in the emergency department (ED) setting.

METHODS

Children ages 6 months to 18 years presenting to participating EDs with SSTIs ≥ 1 cm were eligible. All treatment decisions, including use of POCUS, were at the discretion of the treating clinicians. Patients were divided into those managed with POCUS guidance (POCUS group) and those managed using clinical assessment alone (non-POCUS group). Primary outcome was clinical treatment failure at 7-10 days (unscheduled ED return visit or admission, procedural intervention, change in antibiotics therapy). Secondary outcomes were ED length of stay, discharge rate, use of alternative imaging, and need for procedural sedation. POCUS utility and impact on management decisions were also assessed by treating clinicians.

RESULTS

In total, 321 subjects (327 lesions) were analyzed, of which 299 (93%) had completed follow-up. There was no significant difference between the POCUS and non-POCUS groups in any of the primary or secondary outcomes. Management plan was changed in the POCUS group in 22.9% of cases (13.8% from medical to surgical, 9.1% from surgical to medical). Clinicians reported increased benefit of POCUS in cases of higher clinical uncertainty.

CONCLUSIONS

Use of POCUS was not associated with decreased ED treatment failure rate or process outcomes in pediatric SSTI patients. However, POCUS changed the management plan in approximately one in four cases.

Point of care ultrasonography in the pediatric emergency department

IMPORTANCE

Point-of-care ultrasonography (POCUS) allows to obtain real-time images to correlate with the patient's presenting signs and symptoms. It can be used by various specialties and may be broadly divided into diagnostic and procedural applications.

OBJECTIVE

We aimed at reviewing current knowledge on the use of POCUS in Pediatric Emergency Departments (PEDs).

FINDINGS

US diagnostic capacity in paediatric patients with suspected pneumonia has been studied and debated whereas literature regarding the usefulness of point-of-care echocardiography in the pediatric setting is still limited. Similarly, Focused Assessment with Sonography for Trauma (FAST) has become a standard procedure in adult emergency medicine but it is still not well codified in the pediatric practice. Concerning procedural applications of POCUS we identified 4 main groups: peripheral vascular access, bladder catheterizations, identification and drainage of abnormal fluid collections and foreign body identification.

CONCLUSIONS AND RELEVANCE

Bedside emergency ultrasound is routinely used by adult emergency physicians and in the last 10 years its application is recognized and applied in PED. Pediatric emergency physicians are encouraged to familiarize with POCUS as it is a safe technology and can be extremely helpful in performing diagnosis, managing critical situations and guiding procedures, which results in globally improving pediatric patients care.

Interventions to Increase Point-of-Care Ultrasound Use in a Pediatric Emergency Department

OBJECTIVE

We sought to determine which interventions have effectively increased point-of-care ultrasound (US) use in a pediatric emergency department (ED).

DESIGN/METHODS

We evaluated the impact of specific interventions conducted over a 5-year period (2010-2015) on point-of-care US performance in a tertiary care pediatric ED. Ultrasound use by attending physicians and fellows was ascertained from a departmental database. Interventions assessed included the following: (1) initiation of an US fellowship, (2) acquisition of a second US machine, (3) performance of an US-related research project in the department, (4) initiation of faculty US curriculum, (5) earlier introduction of US education for pediatric emergency medicine fellows, and (6) administrative mandate dictating faculty requirements for credentialing. Mean monthly US use was trended over time using statistical process control methodology, and the impact of major interventions was analyzed using interrupted time-series analyses.

RESULTS

The mean number of US scans increased from 2.0 to 5.9 per attending per month and from 4.3 to 7.1 per fellow per month over the study period. Using interrupted time-series analyses, we observed the only intervention to significantly increase attending US utilization was an administrative credentialing mandate, with an associated increase of 6% per month (incidence rate ratio, 1.06; 95% confidence interval, 1.01-1.11).

CONCLUSIONS

Point-of-care US use has increased over time for both fellows and attending physicians. We observed that an administrative mandate led to a significant increase in US use among attending physicians.

Pediatric lateral neck infections - Computed tomography vs ultrasound on initial evaluation

OBJECTIVE

Review the evaluation of children with a deep lateral neck infection and define the impact of initial imaging modality on outcomes and costs.

METHOD

Case series, pediatric patients <18 years of age admitted to a tertiary care hospital with lateral neck infection between 01/01/14-05/31/16 as identified by ICD-9 and ICD-10 codes: 289.3 (lymphadenitis, unspecified), 682.1 (cellulitis and abscess of neck), 683 (acute lymphadenitis), I88.9 (nonspecific lymphadenitis, unspecified), L02.11 (cutaneous abscess of neck), L03.221 (cellulitis of neck), and L03.222 (acute lymphangitis of neck). Patients were divided into two groups based on initial imaging modality: primary ultrasound or primary computed tomography. Differences in length of stay, type and total number of imaging studies obtained, number of procedures, hospital readmission, and hospital cost were compared between cohorts.

RESULTS

There were 40 (31%) primary ultrasound and 88 (69%) primary computed tomography patients (128 total). Median length of stay was 46 (IQR: 25,90) hours (1.9 days) for primary ultrasound and 63 (IQR: 39,88) hours (2.6 days) for primary computed tomography patients (p = 0.33). Drainage was performed in 48% of both groups. Additional imaging occurred in 17 (43%) primary ultrasound and 18 (20%) primary computed tomography patients (p = 0.02). Readmission occurred in 8 patients (6.3%). Retropharyngeal infection was encountered in 13 patients (10%); this was only discovered in patients who had a computed tomography performed. Median cost per primary ultrasound patients was $5363 (IQR: 3011, 7920) and $5992 (IQR: 3450, 8060) for primary computed tomography patients.

CONCLUSIONS

The primary imaging modality (ultrasound or computed tomography) used to work-up children with a lateral neck infection did not impact length of stay or hospital cost. However, a significant subset had a coexisting retropharyngeal infection that was only identified on computed tomography. Future studies are needed to identify appropriate criteria for imaging in the work-up of lateral neck infections.

What is new in the management of skin and soft tissue infections in 2016?

PURPOSE OF REVIEW

Skin and soft tissue infections (SSTIs) are the most frequent infectious cause of referrals to emergency departments and hospital admissions in developed world, contributing to significant morbidity and healthcare expenditures. We sought to review recent literature covering epidemiology and management of SSTIs.

RECENT FINDINGS

Incidence trends of SSTIs were increasing worldwide with Staphylococcus aureus and streptococci predominating and methicillin-resistant S. aureus (MRSA) posing additional challenges, because of high rates of treatment failure and relapse. Development of new antimicrobials was associated with an appraisal of regulatory definitions and endpoints. Prediction of clinical response can be very tricky, because of variable risk factors for recurrence or treatment failure, depending mostly on the host. Precise indications for new antimicrobials should be established; their integration into clinical practice algorithms may serve reduction of unnecessary admissions, overtreatment and total costs.

SUMMARY

New antimicrobials with activity against MRSA have been recently launched. Long-acting agents, mainly oritavancin and dalbavancin, provide the opportunity of single-dose treatment and early discharge. Further outpatient treatment options include new per os antibiotics such as oxazolidinones. Validated assessment tools are urgently needed to support decision-making toward rational resource utilization and delivery of optimal treatment.

Ultrasound-Guided Drainage for Pediatric Soft Tissue Abscesses Decreases Clinical Failure Rates Compared to Drainage Without Ultrasound: A Retrospective Study

OBJECTIVES

Soft tissue abscesses are common in the pediatric emergency department (ED). Ultrasound (US) can be used to both diagnose soft tissue abscesses as well as guide drainage. We hypothesized that clinical failure rates would be less in pediatric patients with suspected skin abscesses when evaluated with US.

METHODS

We performed a retrospective review of suspected pediatric skin abscesses at 4 EDs over a 22-month period. Cases were identified through electronic medical record descriptions, discharge diagnoses, and US database records. Data on US use, findings, and outcomes were abstracted to an electronic database. Comparisons between groups included US versus non-US (primary outcome) as well as surgical drainage vs nonsurgical drainage (secondary outcome).

RESULTS

A total of 377 patients were seen with concern for a potential skin abscess; 141 patients (37.4%) underwent US imaging during their visit, and 239 (63.4%) underwent incision and drainage (I&D) during their ED stay: 90 with US and 149 without. The failure rate for patients evaluated with US was significantly lower than that for those evaluated without US (4.4% versus 15.6%; P < .005). Thirty-four (11.3%) of the 302 patients with a diagnosis of an abscess failed therapy: 19 (8.2%) after I&D and 15 (21.1%) after nonsurgical management. Failure after I&D was associated with a smaller abscess cavity on US imaging (17.2 versus 44.8 mm³ ; P < .05).

CONCLUSIONS

The use of US for patients with a suspected skin abscess was associated with a reduction in the amount of clinical failure rates after both surgical drainage and nonsurgical therapy. Ultrasound should be used when evaluating or treating patients with abscesses.

In patients presenting to the emergency department with skin and soft tissue infections what is the diagnostic accuracy of point-of-care ultrasonography for the diagnosis of abscess compared to the current standard of care? A systematic review and meta-analysis

OBJECTIVES

The primary objective of this systematic review was to determine the accuracy of point-of-care ultrasonography (POCUS) in diagnosing abscess in emergency department (ED) patients with skin and soft tissue infections (SSTI). The secondary objective was the accuracy of POCUS in the paediatric population subgroup.

SETTING

Prospective studies set in emergency departments.

PARTICIPANTS

Emergency department patients (adult and paediatric) presenting with SSTI and suspected abscess.

PRIMARY AND SECONDARY OUTCOME MEASURES

This systematic review was conducted according to Cochrane Handbook guidelines, and the following databases were searched: PubMed, MEDLINE, EMBASE and the Cochrane database of systematic reviews (1946-2015). We included prospective cohort and case-control studies investigating ED patients with SSTI and abscess or cellulitis, a defined POCUS protocol, a clearly defined gold standard for abscess and a contingency table describing sensitivity and specificity. Two reviewers independently ascertained all potentially relevant citations for methodologic quality according to QUADAS-2 criteria. The primary outcome measure was the sensitivity and specificity of POCUS for abscess. A preplanned subgroup (secondary) analysis examined the effects in paediatric populations, and changes in management were explored post hoc.

RESULTS

Of 3028 articles, 8 were identified meeting inclusion criteria; all were rated as good to excellent according to QUADAS-2 criteria. Combined test characteristics of POCUS on the ED diagnosis of abscess for patients with SSTI were as follows: sensitivity 96.2% (95% CI 91.1% to 98.4%), specificity 82.9% (95% CI 60.4% to 93.9%), positive likelihood ratio 5.63 (95% CI 2.2 to 14.6) and negative likelihood ratio 0.05 (95% CI 0.01 to 0.11).

CONCLUSIONS

A total of 8 studies of good-to-excellent quality were included in this review. The use of POCUS helps differentiate abscess from cellulitis in ED patients with SSTI.

TRIAL REGISTRATION NUMBER

CRD42015017115.

Point-of-care Ultrasound for Diagnosis of Abscess in Skin and Soft Tissue Infections

BACKGROUND

Traditionally, emergency department (ED) physicians rely on their clinical examination to differentiate between cellulitis and abscess when evaluating skin and soft tissue infections (SSTI). Management of an abscess requires incision and drainage, whereas cellulitis generally requires a course of antibiotics. Misdiagnosis often results in unnecessary invasive procedures, sedations (for incision and drainage in pediatric patients), or a return ED visit for failed antibiotic therapy.

OBJECTIVE

The objective was to describe the operating characteristics of point-of-care ultrasound (POCUS) compared to clinical examination in identifying abscesses in ED patients with SSTI.

METHODS

We systematically searched Medline, Web of Science, EMBASE, CINAHL, and Cochrane Library databases from inception until May 2015. Trials comparing POCUS with clinical examination to identify abscesses when evaluating SSTI in the ED were included. Trials that included intraoral abscesses or abscess drainage in the operating room were excluded. The presence of an abscess was defined by drainage of pus. The absence of an abscess was defined as no pus drainage upon incision and drainage or resolution of SSTI without pus drainage at follow-up. Quality of trials was assessed using the QUADAS-2 tool. Operating characteristics were reported as sensitivity, specificity, positive likelihood ratio (LR+), and negative likelihood ratio (LR-), with their respective 95% confidence intervals (CI). Summary measures were calculated by generating a hierarchical summary receiver operating characteristic (HSROC) model.

RESULTS

Of 3,203 references identified, six observational studies (four pediatric trials and two adult trials) with a total of 800 patients were included. Two trials compared clinical examination with clinical examination plus POCUS. The other four trials directly compared clinical examination to POCUS. The POCUS HSROC revealed a sensitivity of 97% (95% CI = 94% to 98%), specificity of 83% (95% CI = 75% to 88%), LR+ of 5.5 (95% CI = 3.7 to 8.2), and LR- of 0.04 (95% CI = 0.02 to 0.08).

CONCLUSION

Existing evidence indicates that POCUS is useful in identifying abscess in ED patients with SSTI. In cases where physical examination is equivocal, POCUS can assist physicians to distinguish abscess from cellulitis.