Left ventricular outflow tract (LVOT) obstruction is the most prevalent structural heart defect leading to neonatal collapse presenting to an emergency department, but a significant proportion of cases are initially misdiagnosed, UK research finds.
Cardiac abnormality was one of the most common causes of neonatal collapse, the research team wrote in the journal BMJ Paediatrics Open, with early recognition crucial for timely interventions and referral.
There were different types of cardiac pathology that could cause collapse, requiring different management, but there was minimal literature on the proportions of these presenting to emergency departments and how they were managed prior to being transferred to critical care, they said.
To fill this knowledge gap, the researchers designed a retrospective cohort analysis of cardiac-related neonatal collapses referred to the South Thames Retrieval Service (STRS) of the Evelina London Children’s Hospital – a regional paediatric intensive care retrieval team based in London.
Over the course of the nine-year study (2013-2021), the researchers found LVOT obstruction was the most prevalent cause of cardiac-related neonatal collapse referred to the retrieval service.
In addition, a significant proportion of cardiac-related neonatal collapses were misdiagnosed as non-cardiac pathology at referral, particularly those with LVOT obstruction and cardiomyopathy/myocarditis.
Cardiac-related neonatal collapse findings
There were 71 neonates identified who met the study inclusion criteria of whom 49 (69%) had a structural heart defect, 12 (17%) had arrhythmia and 10 (14%) had cardiomyopathy/myocarditis.
Among those who had structural defects, the majority were related to decreased systemic flow due to LVOT obstruction (71%), followed by abnormal and mixing of circulation (22%).
At referral, the referring team identified a potential cardiac cause in 49 neonates, which accounted for 69% of cases.
In the remaining 22 neonates, the documented provisional diagnoses included sepsis in 12 cases, bronchiolitis in four cases, ‘neonatal collapse’ in four cases, metabolic cause in one case and shock in one case.
Patients with cardiomyopathy/myocarditis (30%) and LVOT obstruction (63%) were under-recognised compared with patients with abnormal mixing of circulation who were all recognised.
The researchers noted that the group with cardiomyopathy/myocarditis remained challenging to diagnose at all time points.
They also found that less than half of neonates with duct-dependent lesions received prostaglandin at referral, however, this improved to 97% during retrieval.
The number of patients requiring intubation and inotropic support also increased at various time points throughout the patient journey.
Among patients with structural defects, 48 (98%) required cardiac interventions at a median of one day after admission, the study found.
The median age at the time of referral was 11 days and the median weight at referral was 3.5kg, which ranged from 1.8kg to 5kg.
A need for early cardiac interventions
Senior author Dr Jon Lillie, consultant in paediatric care at Evelina London Children’s Hospital, and co-authors concluded that the study had identified a gap in diagnostic accuracy among cardiac-related neonatal collapses.
They noted that nearly all patients in the study cohort needed early cardiac interventions, adding that these conditions were likely to deteriorate without timely and appropriate surgical or cardiac catheter invention.
‘Therefore, it is imperative to optimise respiratory and cardiovascular support at presentation and minimise delay in transfer to the cardiac centre to improve survival and clinical outcomes,’ they wrote.
High clinical vigilance should be promoted among healthcare professionals who might encounter neonatal collapse, the authors added. There was also a need for comprehensive assessment, including femoral pulse evaluation, measurement of pre-ductal and post-ductal blood pressures and oxygen saturation levels.
The study authors also recommended a lower threshold for initiating prostaglandin therapy and timely referral for cardiac assessment.
‘Training sessions and clinical guidelines on indications and preparation of prostaglandin infusions may facilitate early administration of the medication,’ they concluded.
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