Postoperative Cerebral Oxygen Saturation in Children After Congenital Cardiac Surgery and Long-Term Total Intelligence Quotient: A Prospective Observational Study

Abstract

Objectives: During the early postoperative period, children with congenital heart disease can suffer from inadequate cerebral perfusion, with possible long-term neurocognitive consequences. Cerebral tissue oxygen saturation can be monitored noninvasively with near-infrared spectroscopy. In this prospective study, we hypothesized that reduced cerebral tissue oxygen saturation and increased intensity and duration of desaturation (defined as cerebral tissue oxygen saturation < 65%) during the early postoperative period, independently increase the probability of reduced total intelligence quotient, 2 years after admission to a PICU.

Design: Single-center, prospective study, performed between 2012 and 2015.

Setting: The PICU of the University Hospitals Leuven, Belgium.

Patients: The study included pediatric patients after surgery for congenital heart disease admitted to the PICU.

Interventions: None.

Measurements and main results: Postoperative cerebral perfusion was characterized with the mean cerebral tissue oxygen saturation and dose of desaturation of the first 12 and 24 hours of cerebral tissue oxygen saturation monitoring. The independent association of postoperative mean cerebral tissue oxygen saturation and dose of desaturation with total intelligence quotient at 2-year follow-up was evaluated with a Bayesian linear regression model adjusted for known confounders. According to a noninformative prior, reduced mean cerebral tissue oxygen saturation during the first 12 hours of monitoring results in a loss of intelligence quotient points at 2 years, with a 90% probability (posterior β estimates [80% credible interval], 0.23 [0.04-0.41]). Similarly, increased dose of cerebral tissue oxygen saturation desaturation would result in a loss of intelligence quotient points at 2 years with a 90% probability (posterior β estimates [80% credible interval], -0.009 [-0.016 to -0.001]).

Conclusions: Increased dose of cerebral tissue oxygen saturation desaturation and reduced mean cerebral tissue oxygen saturation during the early postoperative period independently increase the probability of having a lower total intelligence quotient, 2 years after PICU admission.

Trial registration: ClinicalTrials.gov NCT01706497.

Figure 1.

Sequences of regional cerebral tissue oxygen saturation (Scto₂) recordings, first 12 hr of monitoring time. Signal A desaturation dose: 0%·min, mean Scto₂: 74%. Signal B desaturation dose: 917 %·min; mean Scto₂: 57%. For signal B, the desaturation dose below 65% (unit of measurement: %·min) is represented by the dark-gray area between the signal and the gray dashed line, which indicates the 65% desaturation threshold. According to the enthusiastic prior, there is an 80% probability that the dose of desaturation of signal B results in a loss of 4–15 IQ points as compared with signal A. Similarly, there is an 80% probability that the mean Scto₂ of signal B results in 2.8–7.4 IQ points lower total IQ than signal A 2-yr after pediatric intensive care medicine admission.

Figure 2.

Flow diagram for study participants inclusion. NIRS = near-infrared spectroscopy.

Figure 3.

Comparison between the β priors and β posteriors probability distribution of the skeptical, neutral, and enthusiastic priors of the multivariable Bayesian model on the relation between mean regional cerebral tissue oxygen saturation (Scto₂) and total IQ. Only the distributions of the β estimate of the mean Scto₂ (first 12 hr of monitoring time) are shown.