Perioperative cerebral hemodynamics and oxygen metabolism in neonates with single-ventricle physiology

Abstract

Abstract:Congenital heart disease (CHD) patients are at risk for neurodevelopmental delay. The etiology of these delays is unclear, but abnormal prenatal cerebral maturation and postoperative hemodynamic instability likely play a role. A better understanding of these factors is needed to improve neurodevelopmental outcome. In this study, we used bedside frequency-domain near infrared spectroscopy (FDNIRS) and diffuse correlation spectroscopy (DCS) to assess cerebral hemodynamics and oxygen metabolism in neonates with single-ventricle (SV) CHD undergoing surgery and compared them to controls. Our goals were 1) to compare cerebral hemodynamics between unanesthetized SV and healthy neonates, and 2) to determine if FDNIRS-DCS could detect alterations in cerebral hemodynamics beyond cerebral hemoglobin oxygen saturation (SO 2 ). Eleven SV neonates were recruited and compared to 13 controls. Preoperatively, SV patients showed decreased cerebral blood flow (CBF i ), cerebral oxygen metabolism (CMRO 2i ) and SO 2 ; and increased oxygen extraction fraction (OEF) compared to controls. Compared to preoperative values, unstable postoperative SV patients had decreased CMRO 2i and CBF i , which returned to baseline when stable. However, SO 2 showed no difference between unstable and stable states. Preoperative SV neonates are flow-limited and show signs of impaired cerebral development compared to controls. FDNIRS-DCS shows potential to improve assessment of cerebral development and postoperative hemodynamics compared to SO 2 alone. References and links 1. J. I. E. Hoffman and S. Kaplan, "The incidence of congenital heart disease," J. Am. Coll. Cardiol. 39, 1890-1900 A. Rappaport, and D. Wypij, "Randomized trial of hematocrit 25% versus 35% during hypothermic cardiopulmonary bypass in infant heart surgery," J. Thorac. Cardiovasc. Surg. 135, 347-54, 354.e1-4 (2008).

Clinical applications of near-infrared diffuse correlation spectroscopy and tomography for tissue blood flow monitoring and imaging

“…In addition to the applications in adults and children, DCS was employed to assess CBF in neonates with malfunctions/defects and during surgical treatments, including those with congenital heart disease (CHD) (Durduran et al , 2010b), hypoxic ischemic encephalopathy (Dehaes et al, 2014), single-ventricle CHD undergoing surgery (Dehaes et al , 2015), as well as the neonates during open heart surgery (Busch et al , 2016b). In those studies, DCS measurements benefited from higher signal-to-noise ratio (SNR) due to the thinner skulls of neonates.…”

“…Apart from physiological challenging mentioned above, CBF values before and after heart surgeries were measured and compared between the neonates with single-ventricle CHD and healthy controls (Dehaes et al , 2015). The results showed impaired cerebral development in diseased neonates, as characterized by decreased CBF.…”

Time-domain diffuse correlation spectroscopy

“…Hemoglobin oxygenation depends on both perfusion and consumption and cannot disentangle changes in the flow and oxygen metabolism [2,3]. The use of CBV as a surrogate of CBF is based on the Grubb relationship [4], which fails during fast dynamic changes [5] and with disease [6,7] or altered physiology [8,9]. NIRS can also estimate CBF from manipulations of expired oxygen [10] or boluses of injected dyes like indocyanine green [11], but these methods are more invasive and cannot provide continuous monitoring.…”

Assessing the effects of subject motion on T2 relaxation under spin tagging (TRUST) cerebral oxygenation measurements using volume navigators

“…Despite these caveats, a 7.4‐ms bias in T 2 is important given that it exceeds the largest same subject SD in T 2 observed in this study (3.9 ms; Table ) and the mean same subject SD given in a study investigating the test‐retest characteristics of TRUST (4.5 ms, calculated from the SvO 2 results in Liu et al by assuming a hematocrit of 0.4, SvO 2 of 62% , and a τ CPMG of 10 ms). Potential bias attributed to motion alone (3.9% absolute SO 2 ) is greater than half the observed group difference in SvO 2 in some studies of neonates with congenital heart disease (7.5% absolute SO 2 ) .…”