Cerebral Oxygen Saturation in Children With Congenital Heart Disease and Chronic Hypoxemia

Abstract

Background Increased Hb concentration accompanying hypoxemia is a compensatory response to maintain tissue oxygen delivery (DO2). Near infrared spectroscopy (NIRS) is used clinically to detect abnormalities in the balance of cerebral DO2 and consumption, including in children with congenital heart disease (CHD). Although NIRS-measured cerebral tissue O2 saturation (ScO2) correlates with SaO2, jugular bulb O2 saturation (SjbO2), and Hb, little data exists on the interplay between these factors and cerebral O2 extraction (COE). This study investigated the associations of ScO2 and ΔSaO2–ScO2 with SaO2 and Hb and verified the normal range of ScO2 in children with CHD. Methods Children undergoing cardiac catheterization for CHD were enrolled in a calibration and validation study of the FORE-SIGHT® NIRS monitor. Two pairs of simultaneous arterial and jugular bulb samples were drawn for co-oximetry, calculation of a reference ScO2 (REF CX), and estimation of COE. Pearson correlation and linear regression were used to determine relationships between O2 saturation parameters and Hb. Data were also analyzed according to diagnostic group defined as acyanotic (SaO2 ≥ 90%) and cyanotic (SaO2 < 90%). Results Of 65 children studied, acceptable jugular bulb samples (SjbO2 absolute difference between samples ≤ 10%) were obtained in 57 (88%). The ΔSaO2–SjbO2, ΔSaO2–ScO2, and ΔSaO2−REF CX were positively correlated with SaO2 and negatively correlated with Hb (all P < 0.001). Although by diagnostic group ScO2 differed statistically (P = 0.002), values in the cyanotic patients were within the range considered normal (69 ± 6%). COE estimated by the difference between arterial and jugular bulb O2 content (ΔCaO2−CjbO2, mL O2/100 mL) was not different for cyanotic and acyanotic patients (P = 0.10), but estimates using ΔSaO2–SjbO2, ΔSaO2–ScO2, or ΔSaO2–ScO2/SaO2 were significantly different between the cyanotic and acyanotic children (P < 0.001). Conclusions Children with adequately compensated chronic hypoxemia appear to have ScO2 values within the normal range. The ΔSaO2–ScO2 is inversely related to Hb, with the implication that in the presence of reduced Hb, particularly if coupled with a decreased cardiac output, the ScO2 can fall to values associated with brain injury in laboratory studies.

A practical approach to cerebral near‐infrared spectroscopy (NIRS) directed hemodynamic management in noncardiac pediatric anesthesia

“…A closer look at NIRS monitoring in children with cyanotic heart disease nicely illustrates the fundamental difference between NIRS and pulse oximetry. 39,40 While the pulse oximeter shows an oxygen saturation of 85%, NIRS-derived c-rSO 2 values are around 70%, equaling the range usually seen in awake healthy children with an oxygen saturation of ±98%. This equality in c-rSO 2 values can easily be ex- between 33% and 44% for acute brain energy failure and brain metabolic dysfunction.…”

ED50 of Intranasal Dexmedetomidine Sedation for Transthoracic Echocardiography in Children with or without a History of Cardiac Surgery for Cyanotic Congenital Heart Disease

“…An overview of the literature shows that surgery has little impact on ED50 of cCHD, which may suggest a meaningful potential implication: the intrinsic internal milieu of cCHD children makes their requirement for drug dosage different from children with other diseases, whether or not there is a history of surgery and sedation. The possible reasons are as follows: first, anatomically, there is a right-to-left shunting or obstruction in cCHD, which then produces a unique change in the internal milieu, affecting the metabolism and pharmacokinetics [ 22 ], or even the growth and development of the central nervous system (CNS) [ 23 ], which further affects the depth and duration of sedation, and finally leading to the requirement of the patient for different anesthetics and sedatives.…”

Changes in Near-Infrared Spectroscopy After Congenital Cyanotic Heart Surgery

“…Arterial oxygen saturation measured by SpO 2 increases after surgical correction of cyanotic CHD. CrO 2 , measuring the concentration of hemoglobin and oxy-hemoglobin in arterioles, capillaries and venules reflects cerebral tissue oxygenation which is taken as a surrogate of cerebral venous oxygenation (SvO 2 ) ( 14 , 15 ). In this observational study, the CrO 2 remains the same.…”