The scenarios of shock in newborn infants

Abstract

Shock defines a complex dysfunction of organ perfusion, that produces a status of cellular energy failure, resulting from an insufficient supply of oxygen and nutrients to tissues. The diagnosis of shock is very difficult because of the lack of sufficiently sensitive and specific clinical criteria, and is substantially based on the demonstration of an arterial hypotension, an indicator unfit to detect the organ hypoperfusion. It determines the necessity of firmly introducing in the diagnostic run the functional echocardiography, the near infrared spectroscopy and the amplitude – integrated electroencephalography, etc., in the monitoring of the critical newborn. In order to simplify the problem, the authors identify the clinical scenarios of the newborn's shock to enhance the different pathogenetic moments and to build up appropriate therapeutic algorithms, without forgetting that at present there is no evidence that treatment of shock improves outcomes, despite the large amount of the studies conducted on this topic.

What’s new in the treatment of neonatal shock

“…The measurement of flow at the level of the superior vena cava (SVC) is particulary useful, representing flow returning from the head and upper body and being a proxy for the total systemic blood flow. A SVC flow > 40 mL/Kg/min is recommended as well as a cardiac index (CI) > 3.3 L/min/m 2 , absence of right-to-left shunting, tricuspid regurgitation, or right ventricular failure (5).…”

Use of Antihypotensive Therapies in Extremely Preterm Infants

“…These infants appear to be at greater risk of a poor outcome, 4,24,25,31,32 and in this scenario, the benefits of therapy may outweigh the risks even though neither can be accurately predicted. 1,2,22,33 However, infants with perceived low BP usually have adequate perfusion, 23,25,34,35 and the benefit of treatment has not been established for these infants. In this situation, therapies to increase BP appear also to be used to try to prevent or improve undocumented organ hypoperfusion, primarily cerebral blood flow.…”

“…In this situation, therapies to increase BP appear also to be used to try to prevent or improve undocumented organ hypoperfusion, primarily cerebral blood flow. 34,35 This approach is challenging because BP may not correlate with perfusion [34][35][36][37] ; infants with low BP may have adequate cerebral blood flow, 25,35,38,39 vasoactive drugs do not always increase cerebral perfusion 25,34 and have not improved outcomes, 40 and treatment of low BP has been associated with similar or worse rates of intracranial abnormalities and impaired neurodevelopment versus matched untreated infants. [3][4][5]17,22,23 These factors make it difficult to determine if an extremely preterm infant with perceived low BP but clinically adequate perfusion would benefit from or be harmed by therapy.…”

Postnatal neonatal myocardial adaptation is associated with loss of tolerance to tachycardia: a simultaneous invasive and noninvasive assessment

“…Understanding the functional nature of the neonatal myocardium and how it evolves through the first few weeks and months after birth is key to optimizing care. Although many authors have provided their opinions regarding clinical management strategies (1,12,32), more translational and clinical studies are needed to provide insight into the functional capacity of the early postnatal heart. In particular, changes in diastolic reserve during the first few weeks and months of life in relation to the known disproportionate left ventricular (LV) growth (3,27) have been poorly explored.…”