Utility of Point of Care Ultrasound for Intussusception

Abstract

Source: Bergmann KR, Arroyo AC, Tessaro MO, et al. Diagnostic accuracy of point-of-care ultrasound for intussusception: a multicenter, non-inferiority study of paired diagnostic tests. Ann Emerg Med. 2021 Nov;78(5):606-615; doi:10.1016/j.annemergmed.2021.04.033Investigators from multiple institutions conducted a prospective study to assess the accuracy of point of care ultrasounds (POCUS), performed by trained pediatric emergency physicians, for the diagnosis of intussusception in young children. Study patients were children 3 months to 6 years old, presenting with clinical suspicion of intussusception to 17 pediatric EDs in North and Central America, Europe, and Australia between 2018 and 2020. POCUS were performed by pediatric emergency physicians who had completed an ultrasound fellowship, had a registered diagnostic medical sonographer designation, or had previously completed ≥20 abdominal POCUS examinations. A radiology- performed ultrasound (RADUS) also was obtained on study patients. POCUS studies were considered positive for intussusception if a target-shaped mass ≥2.0 cm was identified, and/or if the pediatric emergency physician determined that there was an intussusception that required intervention. For RADUS examinations, the diagnosis of intussusception was based on the attending radiologist’s interpretation. The primary outcome was clinically important intussusception, defined as an intussusception requiring radiographic (ie, enema) or surgical reduction within 7 days of the index ED visit.The accuracy of POCUS (defined as true positives plus true negatives divided by total number of examinations) and RADUS were determined, as well as the sensitivity and specificity of both in predicting intussusception. The difference in accuracy between RADUS and POCUS was assessed with a mixed-effects model, with the physician conducting the POCUS exam included as a random effects term. A priori, it was determined that if the upper limits of the 95% CI of the difference was <4 percentage points, POCUS was non-inferior to RADUS as a method to diagnose intussusception.Data were analyzed on 256 children with a median age of 21.1 months. The most common chief complaints among these patients were abdominal pain (82.8%) and fussiness (80.5%). A total of 58 patients (22.7%) had clinically important intussusceptions. POCUS examinations were conducted by 35 pediatric emergency physicians. The accuracy of POCUS examinations in diagnosing intussusception was 97.7% (95% CI, 94.9, 99.0), with a sensitivity of 96.6% (95% CI, 87.2, 99.1) and a specificity of 98.0% (95% CI, 94.7, 99.2). For RADUS, the accuracy was 99.3% (95% CI, 96.8, 99.9), sensitivity 98.3% (95% CI, 88.7, 99.8), and specificity 99.5% (95% CI, 96.5, 99.9). The difference in accuracy between POCUS and RADUS examinations was 1.5 percentage points (95% CI, -0.6, 3.6), thus meeting the criterion for non- inferiority of POCUS compared to RADUS for diagnosing intussusception.The authors conclude that the accuracy of POCUS performed by experienced clinicians was non-inferior to that of RADUS in diagnosing intussusception in young children.Dr Bechtel has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.Intussusception is the most common cause of bowel obstruction in children younger than 6 years old;1 fussiness and abdominal pain symptoms can be protean in this age group. Therefore, having a reliable screening tool to detect intussusception that does not involve radiographs (See AAP Grand Rounds. 2011;25[4]:41.)2 and is performed at the bedside in the ED would be helpful. In addition, such a tool would reduce ED length of stay and conserve resources, such as transferring to a tertiary care pediatric hospital for RADUS or reduction air enema. Indeed, the authors found that POCUS was not inferior to RADUS for the detection of intussusception in the ED setting when performed by experienced ED providers.There are several strengths of the current study. It was the most extensive prospective study to date, with a heterogeneous sample that showed a low rate of serious complications. The investigators evaluated only clinically meaningful intussusception (ileocolic). Interrater reliability for POCUS studies was high, as was agreement between POCUS and RADUS for secondary sonographic findings. POCUS may lead to a more focused evaluation, omitting unnecessary laboratory evaluation and radiographs and facilitating more appropriate transfer for definitive RADUS or air reduction enema if initial POCUS is positive. These findings suggest that POCUS may have utility as a screening tool for children with suspected intussusception when used by experienced ED providers.It is important to note that the false-negative rate was relatively low, with only 2 cases, 1 of which was misclassified as ileoileal but was ileocolic intussusception. However, study investigators could not contact 25.8% of participants, who could have had complications unknown to the study investigators after POCUS. Thus, further prospective study of routine use of POCUS to detect intussusception is needed, especially by less experienced clinicians.Bedside POCUS may be helpful as a diagnostic screening tool for intussusception in the ED.We have repeatedly touted the benefits—potential and realized—of POCUS for diagnosis of diverse disease entities (eg, pneumonia, skull fracture). (See AAP Grand Rounds. 2020;44(3):33.)3 The results of the current study underscore both the utility of POCUS and need to consider proficiency in POCUS for all pediatric residents.