End-organ saturations correlate with aortic blood flow estimates by echocardiography in the extremely premature newborn – an observational cohort study

Abstract

Background Near-infrared spectroscopy (NIRS) measures of cerebral saturation (Csat) and renal saturation (Rsat) in extreme premature newborns may be affected by systemic blood flow fluctuations. Despite increasing clinical use of NIRS to monitor tissue saturation in the premature infant, validation of NIRS measures as a correlate of blood flow is still needed. We compared echocardiography (ECHO) derived markers of ascending aorta (AscAo) and descending aorta (DesAo) blood flow with NIRS measurements obtained during the ECHO. Methods Newborns < 29 weeks’ gestation (2013–2017) underwent routine NIRS monitoring. Csat, Rsat and systemic saturation at the time of ECHO were retrospectively analyzed and compared with Doppler markers of aortic flow. Renal and cerebral fractional tissue oxygen extraction (rFTOE and cFTOE, respectively) were calculated. Mixed effects models evaluated the association between NIRS and Doppler markers. Results Forty-nine neonates with 75 Csat-ECHO and 62 Rsat-ECHO observations were studied. Mean post-menstrual age was 28.3 ± 3.8 weeks during the ECHO. Preductal measures including AscAo velocity time integral (VTI) and AscAo output were correlated with Csat or cFTOE, while postductal measures including DesAo VTI, DesAo peak systolic velocity, and estimated DesAo output were more closely correlated with Rsat or rFTOE. Conclusions NIRS measures are associated with aortic blood flow measurements by ECHO in the extremely premature population. NIRS is a tool to consider when following end organ perfusion in the preterm infant.

Routine Diaper Change Alters Kidney Oxygenation in Premature Infants

“…RrSO 2 measured by NIRS strongly correlates with post-ductal aortic blood flow measured by an echocardiogram in extremely premature infants, indicating lower body hypoperfusion may be reliably captured with continuous RrSO 2 monitoring. 20 Several studies have defined population RrSO 2 estimates for the first few weeks of life in premature infants. [21][22][23][24][25][26] Data suggest RrSO 2 values begin relatively high and subsequently decline and plateau over the first 5 to 7 days of life between 45% and 80%; however, infants of lower gestational age have overall lower levels than those of higher gestational age.…”

“…RrSO 2 measured by NIRS strongly correlates with post-ductal aortic blood flow measured by an echocardiogram in extremely premature infants, indicating lower body hypoperfusion may be reliably captured with continuous RrSO 2 monitoring 20. Several studies have defined population RrSO 2 estimates for the first few weeks of life in premature infants 21–26.…”

Impact of Medical Treatment of Hemodynamically Significant Patent Ductus Arteriosus on Cerebral and Renal Tissue Oxygenation Measured by Near-Infrared Spectroscopy in Very Low-Birth-Weight Infants

“…Moreover, the ductal shunt occurs predominantly from the lower rather than the upper body circulation [37]. Cerebral rSpO 2 is primarily affected by pre-ductal systemic perfusion and cerebral oxygen extraction, while renal oxygenation is impacted by post-ductal diastolic steal [38].…”