Cerebral oximetry in preterm infants with respiratory disease: The effects of age and weight on cerebral oxygenation

Abstract

Objective: To evaluate the effects of brief systemic hypoxia on cerebral tissue saturation in premature infants with respiratory disease. We hypothesized that healthy premature infants have a direct relationship between arterial oxygen saturation (SpO₂) and cerebral oxygen saturation (SctO₂) and that the nature of the relationship is associated with demographic markers of maturation. Furthermore, we hypothesized that most infants can maintain adequate cerebral tissue saturation during brief periods of systemic hypoxia. Study design: Twenty-four preterm neonates with respiratory disease were enrolled and monitored for 72 hours using simultaneous pulse oximetry (to detect SpO₂) and cerebral tissue oximetry (to detect SctO₂). The relationship between SpO₂ and SctO₂ and demographic markers of maturation were analyzed, using linear and non-parametric regression methods. Result: As expected, SctO₂ decreased linearly with decreased SpO₂. The drop rate of SctO₂ significantly increased in relation to SpO₂ with decreasing gestational age, corrected gestational age and weight (both birth weight and weight at time of study) but not post-natal age. Conclusion: Healthy premature infants with isolated respiratory disease can maintain adequate cerebral tissue saturations during periods of brief hypoxemia without requiring additional intervention. Each infant has a unique ability to regulate cerebral oxygenation, which appears to be associated with advancing gestational age and increasing weight.