Evaluation of hemodynamics in healthy term neonates using ultrasonic cardiac output monitor

Abstract

Background: Transition from intrauterine to extrauterine life is a critical phase during which several changes occur in cardiovascular system. In clinical practice, it is important to have a method that allows an easy, rapid and precise evaluation of hemodynamic status of a newborn for clinical management. We here propose a rapid, broadly applicable method to monitor cardiovascular function using ultrasonic cardiac output monitoring (USCOM). Methods: We here present data obtained from a cohort of healthy term newborns (n = 43) born by programmed cesarean section at Fondazione MBBM, Ospedale San Gerardo. Measurements were performed during the first hour of life, then at 6 + 2, at 12-24, and 48 h of life. We performed a screening echocardiography to identify a patent duct at 24 h and, if patent, it was repeated at 48 h of life. Results: We show that physiologically, during the first 48 h of life, blood pressure and systemic vascular resistance gradually increase, while there is a concomitant reduction in stroke volume, cardiac output, and cardiac index. The presence of patent ductus arteriosus significantly reduces cardiac output (p = 0.006) and stroke volume (p = 0.023). Furthermore, newborns born at 37 weeks of gestational age display significantly lower cardiac output (p < 0.001), cardiac index (p = 0.045) and stroke volume (p < 0.001) compared to newborns born at 38 and ≥ 39 weeks. Finally, birth-weight (whether adequate, small or large for gestational age) significantly affects blood pressure (p = 0.0349), stroke volume (p < 0.0001), cardiac output (p < 0.0001) and cardiac index (p = 0.0004). In particular, LGA infants display a transient increase in cardiac index, cardiac output and stroke volume up to 24 h of life; showing a different behavior from AGA and SGA infants. Conclusions: Compared to previous studies, we expanded measurements to longer time-points and we analyzed the impact of commonly used clinical variables on hemodynamics during transition phase thus making our data clinically applicable in daily routine. We calculate reference values for each population, which can be of clinical relevance for quick bedside evaluation in neonatal intensive care unit.

Effect of assessing velocity time integral at different locations across ventricular outflow tracts when calculating cardiac output in neonates

“…Several prior studies have described CO in healthy term neonates measured non-invasively via transthoracic echocardiography to be approximately 135 to 325 mL/kg/min [ 2 , 8 – 10 ]. The reason for this variation in CO is likely related to the presence of intracardiac shunts and PDA in neonates, inconsistency in methodology in acquiring CSA and VTI of the ventricular outflow tract, and/or the timing when the echocardiography is obtained as studies have shown that CO increases over 24 h after birth and then remains stable between 24 and 72 h [ 11 , 12 ]. Both Beker et al [ 13 ] and Pereira et al [ 14 ] described variation in left ventricular (LV) CO depending on the position where the ventricular outflow tract diameter is measured.…”

The guiding value of inferior vena cava diameter, inferior vena cava collapse index and inferior vena cava to abdominal aorta ratio in neonates with early onset septic shock

“…Those without sepsis or shock (control group) 48 hours to one week after birth were enrolled, as blood pressure and vascular resistance increase while cardiac output and index decrease in the rst 48 hours [7].…”