Brain tissue oxygen regulation in awake and anesthetized neonates

Abstract

Inhaled general anesthetics are used commonly in adults and children, and a growing body of literature from animals and humans suggests that exposure to anesthesia at an early age can impact brain development. While the origin of these effects is not well understood, it is known that anesthesia can disrupt oxygen regulation in the brain, which is critically important for maintaining healthy brain function. Here we investigated how anesthesia affected brain tissue oxygen regulation in neonatal rabbits by comparing brain tissue oxygen and single unit activity in the awake and anesthetized states. We tested two common general anesthetics, isoflurane and sevoflurane, delivered in both air and 80% oxygen. Our findings show that general anesthetics can greatly increase brain tissue PO in neonates, especially when combined with supplemental oxygen. Although isoflurane and sevoflurane belong to the same class of anesthetics, notable differences were observed in their effects upon neuronal activity and spontaneous respiration. Our findings point to the need to consider the potential effects of hyperoxia when supplemental oxygen is utilized, particularly in children and neonates.

Effects of neonatal isoflurane anesthesia exposure on learning-specific and sensory systems in adults

“…Our previous findings also point to hyperoxia as a potential risk factor during anesthesia delivery. Using direct electrode measurements of oxygen concentration, we found that anesthesia delivered in 80% oxygen greatly increased (by up to 300%) oxygen concentration in the cortex of neonates 18 . It is known that the generation of reactive oxygen species directly depends on the concentration of oxygen 30 and can lead to a variety of pathological effects in the brain 31 – 33 .…”

“…One such potential factor is the level of oxygen. In a previous study 18 we recorded a large increase of brain partial oxygen pressure during anesthesia, especially when combined with 80% oxygen, which has the potential to cause hyperoxic damage via the generation of reactive oxygen species 19 . Thus, we tested anesthesia delivery in air as well as in 80% oxygen to gauge the impact of oxygen on anesthesia-induced damage.…”

Behavior and Regional Cortical BOLD Signal Fluctuations Are Altered in Adult Rabbits After Neonatal Volatile Anesthetic Exposure

“…The dominant frequency of brain tissue oxygen oscillations (BTOO), which are attributed to vasomotion at the level of arterioles (Hudetz et al, 1998;Aalkjaer et al, 2011;Mateo et al, 2017), has been shown to change during development (Doubovikov and Aksenov, 2020). The dominant frequency of BTOO is around 1-2 cycles/min (0.0167-0.0333 Hz) in neonates (Aksenov et al, 2018) and approximately 10 cycles/min (0.167 Hz) in adults (Linsenmeier et al, 2016). Based on our findings, it is possible that neonatal anesthesia may disrupt normal developmental shift to higher frequency range of vasomotion, which could manifest as an increase in ALFF in adulthood.…”

Normal Development of Local Neurovascular Interactions and the Diagnostic Value of Resting State Functional MRI in Neurovascular Deficiency Based on the Example of Neonatal Anesthesia Exposure

“…Arteriolar vasomotion follows a typical developmental trajectory. In adults, it is characterized by a 10 cycles per minute (cpm) dominant power frequency ( 35 , 36 ), whereas underdeveloped vasomotion has a dominant frequency below 3 cpm ( 37 ). This shift in frequency of vasomotion and corresponding brain tissue oxygen oscillations represents a normal development and is needed to prevent localized hypoxia depending on the oxygen demand by developing neurons and neuronal networks ( 36 ).…”