Haemodynamically unstable preterm infant: an unresolved management conundrum

Abstract

While extremely low-birthweight infants are at a higher risk of haemodynamic instability, management strategies can be highly variable and may lack scientific validation. The aetiology of cardiovascular compromise can be diverse. Volume replacements, cardiotropes (dobutamine, dopamine, epinephrine and milrinone) and hydrocortisone supplementation are common interventions. Most often, therapy is driven by protocol, is based on poorly validated clinical information or is based on the premise that "one therapy fits all". A physiology-driven approach is most needed during transition from intrauterine to extrauterine life surrounding preterm birth, when rapid changes in cardiovascular adaptation occur. The physiologically important determinants of neonatal haemodynamics include cardiac output and systemic vascular resistance, blood pressure, as well as individual organ vascular resistances and blood flows. Three key variables with impact on neonatal haemodynamics, haemodynamically significant ductus arteriosus, systemic blood flow and left ventricular afterload, as well as related therapeutic dilemmas are addressed. Among the novel technologies and approaches presently available, targeted neonatal echocardiography performed by the clinician, used in conjunction with the clinical context, has the potential to better define pathophysiology. A framework for physiology-driven care is proposed, which has the potential to optimize care.

Development of Left Ventricular Longitudinal Speckle Tracking Echocardiography in Very Low Birth Weight Infants with and without Bronchopulmonary Dysplasia during the Neonatal Period

“…This agrees with the findings Seghal et al 2011 achieved using conventional hemodynamic measurements [25]. They described the rapid changes that occur in cardiovascular adaptation during the transition from intrauterine to extrauterine life for preterm birth.…”

Low Cardiac Output Secondary to a Malpositioned Umbilical Venous Catheter: Value of Targeted Neonatal Echocardiography

“…The changes in cardiovascular physiology in the immediate transitional period are highly complex and influenced by right and left ventricular afterload, postnatal myocardial adaptation, ductal and atrial shunts, and the effects of mechanical ventilation and surfactant. TnEcho may provide additional information regarding the physiologic or anatomical nature of cardiovascular impairment in preterm infants, which may either support the clinical suspicion or reveal novel insights 3. An increasing body of evidence supports its use in the management of a PDA9 10 and in infants with pulmonary hypertension 11.…”

Glucocorticoids and foetal heart maturation; implications for prematurity and foetal programming

“…Consequently, haemodynamic instability is a wellrecognised problem in premature infants (Ng et al 2004, Kluckow 2005, Sehgal 2011) with hypotension and low systemic blood flow associated with increased mortality (Ibrahim et al 2011). Many of these markers of prematurity are improved by exogenous glucocorticoid treatment.…”