There is much within the targeted neonatal echocardiography (TNE) consensus statement we endorse, particularly the clinical indications, the need for training structures, and the importance of collaboration with other specialties involved in imaging, especially pediatric cardiology. However, we have concerns.
The proposed terminology of TNE does not clearly identify a study that has excluded congenital heart disease (CHD) from one that has not. The term targeted implicitly undermines the importance of the completeness of an ultrasound examination, and echocardiography is interpreted by many to refer to an examination performed by a cardiologist. Cardiac ultrasound is just one component of neonatal point-of-care ultrasound. We prefer the term clinician-performed cardiac ultrasound (or neonatologist-performed cardiac ultrasound ), which identifies both the organ studied and the acute care role of the clinician operator. Whatever the terminology, the aims defined in section 1.2 of the consensus statement using our original definition of functional echocardiography are “to longitudinally assess myocardial function, systemic and pulmonary blood flow, intracardiac and extracardiac shunts, organ blood flow and tissue perfusion.” This definition makes no mention of CHD, yet there is a bias in this direction in the statement.
The bias is reflected in Table 1, which lists what should be included in TNE. Measurements that have been shown to be useful to assess hemodynamics in the neonatal intensive care unit, such as right ventricular output, pulmonary artery velocity, and superior vena cava flow, are specifically missing from the table. Yet these measures have been studied in hundreds of newborns and reported in more than 35 peer-reviewed publications from different research groups. In contrast, some of the included measures have been shown to be unreliable in newborns (e.g., LV contractility) or are still in the research paradigm (e.g., tissue Doppler) or are validated in adults but inaccurate in newborns (e.g., pulmonary regurgitation). Studying infants using these guidelines will not provide the information required to understand function and physiology.
The risk that needs managing is that CHD will be missed or deemed to have been excluded. We believe that neonatologists can and should learn to recognize common CHD, but it is not our job to exclude it, so we strongly support the need to work closely with pediatric cardiology. Since 2008 in Australasia, we have developed the Neonatal Certificate in Clinician Performed Ultrasound. This has been driven by neonatologists working in collaboration with other specialties. Training requires course attendance and a logbook of 75 cardiac studies (and a similar number of scans of other organs) over a 12-month to 18-month period under the supervision of an accredited Neonatal Certificate in Clinician Performed Ultrasound practitioner and mandatory requirements to engage with a pediatric cardiologist if CHD is suspected clinically or on ultrasound. Establishing a network of accredited supervisors has been a challenge, and this was from a better skill base than would be present in North America, which is coming from an environment of restrictive ultrasound practice. So there is some logic in these proposals as a first step, particularly where there are no neonatologists with ultrasound skills. However, training will become more relevant only when it embraces the training input of neonatologists who have developed point-of-care ultrasound skills.
The proposals as they stand are not geared to the needs of neonatologists, as they are based on a consultative cardiology model and will offer experience in mainly age-inappropriate subjects with CHD. The core requirement for 4 to 6 months of training in a pediatric cardiology echocardiography lab and the number and nature of studies required will be unattainable for most neonatal trainees. This is not the setting in which we work as critical care physicians, in which more than 98% of our scans are performed on infants with normal cardiac structure and abnormal function and in which real-time longitudinal physiologic data are used as an adjunct to other available information in targeting treatment and observing responses.
The United States and Canada lag behind much of the rest of the developed world in the availability of point-of-care ultrasound skills in the neonatal intensive care unit. The proposals of the TNE consensus document are an important first step toward resolving this deficiency, and those involved are to be congratulated, but as they stand, they will fall short of delivering the ultrasound training needs of neonatologists.