The introduction of a new technology into clinical practice is a slow process that includes research, training practitioners, and assessing its gradual diffusion into practice. Point-of-care ultrasound (POCUS) is currently 1 such technology in neonatology. Historically, in pediatrics, ultrasound use has been limited to cardiologists and radiologists. More recently, other pediatric acute care disciplines including pediatric critical care, emergency medicine, anesthesiology, and neonatology have used bedside ultrasound with increasing frequency in procedural and diagnostic applications. The value of POCUS for interventional applications and real-time longitudinal physiologic assessment of sick neonates has been recognized for many years. Despite these benefits, a recent survey revealed that less than one-third of the US Neonatal-Perinatal Medicine programs use bedside ultrasound for diagnostic and management decisions.1
The use of ultrasound to evaluate the pediatric patient’s lungs is relatively new and a potentially revolutionary approach. Over the past 2 decades there have been accumulating data, which allow radiologists and bedside providers to understand the value and the limitations of this imaging modality. Lung ultrasound (LUS) signs (eg, A-lines, B-lines, lung-sliding, etc) are the same among neonatal, pediatric, and adult patients. Among neonates, changes in the presence and absence of these signs occur rapidly after birth. It is only recently that these changes have been systematically documented in a large healthy cohort of term and late-preterm infants.2 A similar rigorous characterization of the ultrasound appearance of the lung in healthy preterm infants at earlier gestational ages has not been published. These findings make the article by De Martino et al3 so important. Here, the authors used POCUS of the lung to develop reliable predictive models for the need for surfactant treatment and redosing in a group of preterm infants (born at a gestational age of 30 weeks or less) who were treated with continuous positive airway pressure and supplemental oxygen of 30% or less.
There are many neonatal disorders in which LUS may have use. The typical ultrasound appearance of pneumothorax and pleural effusions are well established and are essentially the same across age groups.2,4,–6 The diagnostic characteristics of LUS for neonatal diseases, such as transient tachypnea of the newborn, respiratory distress syndrome, meconium aspiration syndrome, and pneumonia, have been described.7,–10 However, although some authors have reported impressive sensitivity and specificity for the technique similar to those presented by De Martino et al3 (reviewed in Kurepa et al6), others have been unable to reproduce these results.7 In addition, it is less clear if LUS can distinguish between certain neonatal respiratory disorders.
To implement LUS into routine neonatal practice, there remain additional significant questions. First, it remains to be seen how wide or narrow the intra- and interobserver variabilities are. In published studies, authors suggest that there is substantial agreement between multiple observers and when a single practitioner repeats the test.11,12 However, such data are from selected nurseries and provider groups without evidence that such performance can be replicated in other less experienced sites. Second, it is unclear at what age the reported studies were performed in previous work and how rapidly these results change in the neonatal lung. As such, it is not known when the ideal time is to perform LUS to optimize the information obtained by the treatment team. Third, one of the challenges in determining the diagnostic validity of LUS is the availability of a gold standard for these pediatric diseases. The gold standard, notwithstanding a pathologic specimen, would be chest computed tomography (CT). Compared with chest CT in older children, LUS and chest radiographs are reported to have comparable sensitivity in the diagnosis of pneumonia, although chest radiographs may be more specific.10 For the purposes of validating ultrasound in a prospective research study, it would unethical to expose infants to the ionizing radiation of a CT scan. Thus, the imperfect gold standard we are left with is a combination of clinical examination and chest radiographs. Finally, we need to examine other subgroups of neonates with differential risks of continuous positive airway pressure treatment failure to demonstrate the generalizability of the test.
Finally, although the potential benefits of POCUS should be the same worldwide, the barriers for implementation vary widely. This is true not only between different countries but also between different institutions within the same country. Although providers in countries such as Australia, New Zealand, and Canada are trained and use POCUS on a daily basis, this is not the case in other countries such as the United States. Possible explanations include perceived medicolegal risks, concerns regarding training, territorial conflicts with cardiology and radiology, the lack of clinicians actively engaged in the technology, and lack of evidence of beneficial impact.13 The development of a POCUS program requires an accessible dedicated ultrasound machine kept in close proximity to clinical areas, a core group of interested clinicians, and a training and accreditation program with a commitment to continuing professional development. Collaboration between critical-care providers and pediatric cardiology and radiology is essential. With this acknowledgment comes the important concept of trust that clinicians will be aware of their own limitations and, when appropriate, refer to other specialists. It is important to understand the limitation of bedside ultrasound, which should always be performed for a specific clinical purpose and to answer a clinical question and does not always mandate a full comprehensive study. In this way, POCUS is designed to improve overall patient care by those physicians at the bedside, while understanding such limitations of bedside ultrasound. This should foster a multidisciplinary collaboration toward a common goal of improved patient outcomes. Through appropriate understanding of the types of information needed in a successful POCUS program, along with the barriers to successful implementation of such a program, we should see successful introduction of this technology into clinical practice.
Opinions expressed in these commentaries are those of the author and not necessarily those of the American Academy of Pediatrics or its Committees.
FUNDING: No external funding.
COMPANION PAPER: A companion to this article can be found online at www.pediatrics.org/cgi/doi/10.1542/peds.2018-0463.
POTENTIAL CONFLICT OF INTEREST: The authors have indicated they have no potential conflicts of interest to disclose.
FINANCIAL DISCLOSURE: The authors have indicated they have no financial relationships relevant to this article to disclose.