Premature infant brain function: are opioid effects evident in the short term?

Opioids, while commonly used in the Neonatal Intensive Care Unit (NICU) for sedation and analgesia during mechanical ventilation, may not be effective for procedural pain. Potential neurologic and sleep disruption after opioid exposure during development is of concern. The immediate effect of opioid therapy has not been fully explored with regard to brain function in early life. The aim of this small n naturalistic study was to describe changes in brain wave signal variability by extracting raw EEG signal from a limited channel amplitude integrated EEG (aEEG) recording and examining differences in spectral density distribution before and after standard morphine administration. Eight infants (2 male) with median postmenstrual age (PMA) 29.4 weeks, underwent a single recording of aEEG, during standard NICU care that included up to two doses of intravenous morphine for analgesia or sedation, 2 infants were status post surgery. Signal processing with fast Fourier transformation (FFT) prepared the data for spectral density analysis. Nine morphine doses provided data at each of two time points (T1= 15 minutes prior, T2 = 30 minutes after). Multivariate repeated measures ANOVA were conducted to test for morphine effect, age effect (PMA <30 weeks) and possible interaction. Morphine effects between time points were not significantly different for measures of 90% spectral edge frequency (SEF90) or high frequency normalized spectral bands alpha (7-13 Hz) or beta (<13 Hz), whereas the age group effect was highly significant: SEF90 (F=42.125 p<.0001), Alpha (F=104.639, p<.0001), Beta (F=11.349, p<.012), an interaction effect was shown for Alpha (F=5.991, p=.044). The exploration of spectral densities may improve understanding of brain function frequency shifts within the spectrum after clinically administered opioids in early premature infants. Support for this study includes: NINR F31- NR011365, T32-NR007106 & NLM 2T15LM007442-11 American Nurses Foundation, Integra Neuroscience Nursing Foundation, Sigma Theta Tau, Psi Chapter at Large.