Oxidative stress: the price of sucrose pain relief in neonates

By Liam Davenport, medwireNews Reporter

Although sucrose significantly reduces the pain experienced by preterm neonates undergoing heel lance, it is associated with significant increases in adenosine triphosphate (ATP) use and oxidative stress, the results of a US study indicate.

The team, led by Danilyn Angeles (Loma Linda University School of Medicine, California), says: "Because neonates can be exposed to numerous painful procedures per day requiring multiple doses of sucrose, randomized trials should be performed to examine the effects of repeated sucrose administration not only on markers of ATP breakdown and oxidative stress but also on cellular injury."

They add in the Journal of Pediatrics: "If it is determined that the metabolic risks of using sucrose in neonates is indeed greater than the known benefits of reducing behavioral indices of pain, additional studies need to be performed to identify alternative effective substances or methods to prevent or treat pain in neonates."

For the study, 131 preterm neonates were randomly assigned to receive heel lance treated with a single oral dose of 24% sucrose and non-nutritive sucking, heel lance treated with placebo and non-nutritive sucking, or a control group (no heel lance).

Pain scores on the Premature Infant Pain Profile (PIPP) were significantly reduced with sucrose, at a procedural mean of 4.6 in the sucrose group versus 6.3 and 5.9 in the placebo and control groups, respectively. However, sucrose group neonates experienced an 11% increase in heart rate, compared with 6% in the placebo group and 0.5% in controls, and there were no significant changes in mean oxygen saturation in any of the three groups.

This suggests that the reduced pain scores in the sucrose group "were attributable to significant reductions in the behavioral components of the PIPP scoring tool and not from physiological markers of pain such as heart rate or oxygen saturation," say the researchers.

The team reports that plasma purine and allantoin concentrations - measures of ATP metabolism and oxidative stress, respectively - decreased in the control and placebo groups. However, there were significant increases in the purines hypoxanthine and uric acid in neonates who received sucrose.

The sucrose group had a nonsignificant increase in allantoin level. However, the 63% of neonates given sucrose who had a minimal response to heel lance (<33% increase in PIPP) had a significant increase in allantoin concentrations. Indeed, analysis revealed a significant correlation between the percentage changes in PIPP score and allantoin concentration over time.

The researchers therefore warn that the "apparent analgesic effect of oral sucrose may come at a price."

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