Hemodynamic monitoring in neonates: advances and challenges

Abstract

Continuous, reliable and real-time assessment of major determinants of cardiovascular function in preterm and term neonates has long been an elusive aim in neonatal medicine. Accordingly, aside from continuous assessment of heart rate, blood pressure and arterial oxygen saturation, bedside monitoring of major determinants of cardiovascular function of significant clinical relevance such as cardiac output, systemic vascular resistance, organ blood flow distribution and tissue oxygen delivery and coupling has only recently become available. Without obtaining reliable information on the changes in and interactions among these parameters in the neonatal patient population during postnatal transition and later in the neonatal period, development of effective and less harmful treatment approaches to cardiovascular compromise is not possible. This paper briefly reviews the recent advances in our understanding of developmental cardiovascular physiology and discusses the methods of bedside assessment of cardiovascular function in general and organ perfusion, tissue oxygen delivery and brain function in particular in preterm and term neonates. The importance of real-time data collection and the need for meticulous validation of the methods recently introduced in the assessment of neonatal cardiovascular function such as echocardiography, electrical impedance cardiometry, near infrared spectroscopy, visible light and laser-Doppler technology are emphasized. A clear understanding of the accuracy, feasibility, reliability and limitations of these methods through thorough validation will result in the most appropriate usage of these methods in clinical research and patient care.

Dose-Dependent Hemodynamic and Metabolic Effects of Vasoactive Medications in Normotensive, Anesthetized Neonatal Piglets

“…Finally, because of the interspecies differences, caution must be exercised when extrapolating the findings on systemic and regional hemodynamics to the human neonate. Accordingly, although the information obtained in this study is useful for the design of interventional clinical trials, future studies using complex hemodynamic monitoring approaches (30) in critically ill neonates need to confirm these findings before the information provided here can be applied to the clinical practice.…”

Volume Expansion Does Not Alter Cerebral Tissue Oxygen Extraction in Preterm Infants with Clinical Signs of Poor Perfusion

“…Firstly, the indications for volume expansion may have been inadequate. Systemic signs of poor perfusion including hypotension may not reflect cerebral underperfusion [15] because MABP is not a direct reflection of organ perfusion [18]. Moreover, critically low blood pressure levels may differ between patients, and some preterm infants continue to have adequate organ perfusion despite their MABP dropping below certain thresholds [19,13].…”

“…before, during and after volume expansion. We used a Student t test to test for differences between one estimated mean and the intercept [18]. To test for differences between two estimated means, we tested the contrast of the sum of the parameters from which each estimate is derived using a χ 2 test with one degree of freedom.…”

Hemodynamic monitoring of the critically ill neonate: An eye on the future

“…However, it must be emphasized that this system also has a number of caveats concerning its accuracy, reliability, feasibility, and the need for validation across different subpopulations [21,22]. The utility power of such monitoring systems lies in the comprehensiveness of the hemodynamic parameters monitored beyond the conventionally obtained parameters of HR, respiratory rate (RR), SpO 2 , BP, and transcutaneous CO 2 measurements.…”