Metabolomics clue to postoperative delirium

Nov 21 2012

By Eleanor McDermid, Senior medwireNews Reporter

The choice of general anesthetic in children influences their cerebral metabolism, which in turn affects their risk for postoperative delirium, an imaging study shows.

Levels of lactate and glucose were significantly higher in the brains of children given sevoflurane than in those given propofol, report Helene Benveniste (Stony Brook University, New York, USA) and co-workers.

"As an increasingly young patient population continues to have a growing need for general anesthesia, it is important to determine the impact inhalant and intravenous anesthetics have on children," said the study authors in a press statement.

The 59 children in the study were aged 2-7 years old and undergoing diagnostic magnetic resonance imaging under general anesthesia, during which the team performed proton magnetic resonance spectroscopy.

This revealed that lactate levels were twofold higher and glucose levels 1.2-fold higher in the parietal cortex of children randomly assigned to receive maintenance anesthesia with sevoflurane versus those given propofol. This difference was independent of age and persisted when the analysis was restricted to children with normal brain scans.

But the researchers say: "The more intriguing finding of this study was the apparent correlation between the PAED [Pediatric Anesthesia Emergence Delirium] score and specific metabolites."

In an exploratory analysis, the children's risk for delirium fell in line with rising total creatine concentrations and rose with increasing lactate and glucose levels, they report in Anesthesiology. Specifically, the children's PAED scores in the recovery suite fell by 4.4 points for each 1 nM increase in creatine and phosphocreatine and rose by 13 points with each 1 nM rise in lactate and glucose.

Benveniste et al note that use of sevoflurane has previously been linked to an increased risk for emergence delirium and has been attributed to factors such as pain. In the present study, the average PAED scores were significantly higher in the sevoflurane versus propofol groups, at 7.0 versus 3.9, but any influence of pain could be ruled out, as all the children underwent noninvasive diagnostic imaging.

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