Neonatal Shock: Current Dilemmas and Future Research Avenues

Neonatal shock presents a complex clinical challenge and is one of the leading causes of mortality. Traditionally, neonatal shock is equated to hypotension, and therapeutics are often initiated based on low blood pressure (BP) values alone. This fails to address the underlying goal of optimizing the tissue perfusion resulting in both over- and under-treatment of neonatal shock. Also, what defines a normal BP in neonates is still a contentious topic. Further, the most appropriate way of measuring BP in neonates with shock is still debated. Shock secondary to transient circulatory instability and patent ductus arteriosus, conditions that are unique to preterm neonates, have not been researched adequately. Treatment of myocardial dysfunction secondary to perinatal asphyxia, a leading cause of neonatal mortality, is still a conundrum. Quite similarly, there are only a handful of controlled trials evaluating therapeutics in some of the other commonly encountered conditions, namely, septic shock and hypoperfusion secondary to pulmonary hypertension. Even the universally practiced intervention of volume expansion with crystalloid boluses in shock is not backed by high-certainty evidence in neonates. Though the diagnostic modalities of functional echocardiography and near-infrared spectroscopy have aided greatly in the management of neonatal shock in recent years, these have not been proven to be associated with improved critical clinical outcomes such as mortality and major brain injury. To conclude, neonatologists often rely on limited evidence, mostly anecdotal, when treating neonatal shock. This review critically examines the current evidence with respect to various aspects of neonatal shock with an objective to identify the lacunae in the literature that may fuel future research, eventually paving the way to efficacious, safe and evidence-based clinical practice.