Should SVC flow be a routine measure when performing targeted neonatal echocardiography? A narrative review.

Superior vena cava is commonly used in neonatal hemodynamics and is suggested to be the best available non-invasive marker for systemic circulation in preterm infants. Inter- and intra-observer variability remain to be an issue. Its association with neonatal outcomes is has not been established. This is a narrative review about this marker, its use, and its potential pitfalls. OBJECTIVE: This is a narrative review about SVC flow in preterm infants, physiology, techniques of measurement and its potential association with outcomes. SOURCES: Literature revie mainly PubMED. SUMMARY OF THE FINDINGS: SVC flow measurement has some limitations and pitfalls. CONCLUSIONS: SVC flow association with neonatal outcomes, still needs to be established in further research.

Effect of sleeping position on cardiac output, pulmonary pressure, and superior vena cava flow in healthy term infants.

BACKGROUND: Although the mechanism of action in newborns is unknown, sleep positioning is associated with many pathophysiological events. This study aimed to compare the effects of supine and prone sleeping positions on cardiac output (CO), systolic pulmonary arterial pressure (SPAP), and superior vena cava (SVC) flow in healthy newborns. METHODS: In the first 24-72 h of life, 40 healthy term newborns born in the same hospital were included in this prospective, cross-sectional, observational study. CO, SVC flow, and SPAP values of newborns in the supine and prone sleeping positions were calculated using echocardiographic examination. The measurements were statistically compared. RESULTS: In the supine sleeping position, CO, SVC flow, and SPAP were 235.00 (193.07-283.30) ml/kg/min, 92.80 (77.82-121.87) ml/kg/min, and 27.85 (24.70-30.48) mmHg. In the prone sleeping position, CO, SVC flow, and SPAP were measured as 195.35 (166.00-229.40) ml/kg/min, 67.25 (51.82-96.66) ml/kg/min, 31.60 (28.45-37.20) mmHg, respectively. Depending on sleeping position, these variables were significantly different between the groups. CONCLUSION: SVC flow and CO decreased in the prone sleeping position compared to the supine sleeping position in healthy newborns, whereas SPAP increased. The different hemodynamic effects of sleeping position on the cardiac, pulmonary, and nervous systems should be considered as flow and pressure changes are important in newborns.

Echocardiographic Quantification of Superior Vena Cava (SVC) Flow in Neonates: Pilot Study of Modified Technique.

Ultrasound Superior Vena Cava (SVC) flow assessment is a common measure of systemic and cerebral perfusion, although accuracy is limited. The aim of this study was to evaluate whether any improvements in accuracy could be achieved by measuring stroke distance from the instantaneous mean velocity, rather than from peak velocity, and by directly tracing area from images obtained with a high frequency linear probe. Paired phase contrast magnetic resonance imaging (PCMRI) and ultrasound assessments of SVC flow were performed in a pilot cohort of 7 infants. Median postnatal age, corrected gestation and weight at scan were 7 (2-74) days, 34.8 (31.7-37.2) weeks 1870 (970-2660) g. Median interval between PCMRI and ultrasound scans was 0.3 (0.2-0.5) h. The methodology trialed here showed a better agreement with PCMRI (mean bias -8 mL/kg/min, LOA -25-+8 mL/kg/min), compared to both the original method reported by Kluckow et al. (mean bias + 42 mL/kg/min, LOA -53-+137 mL/kg/min), and our own prior adaptation (mean bias + 23 mL/kg/min, LOA -25-+71 mL/kg/min). Ultrasound assessment of SVC flow volume using the modifications described led to enhanced accuracy and decreased variability compared to prior techniques in a small cohort of premature infants.