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Very preterm (VPT) infants are exposed to odors released by healthcare products, triggering the trigeminal and olfactory subsystems. Irritation of the nasal mucosa induces pain in adults. We examined whether preterm and full-term (FT) newborns perceived trigeminal odors at different cortical levels, whether these odors elicit pain, and if oral glucose modulates this pain. We performed 44 recording sessions in newborn (15 VPT infants, 12 VPT infants at term-equivalent age, and 17 FT infants) following exposure to trigeminal/olfactory stimuli from the hospital environment. We repeated the exposure after oral glucose administration. We recorded cortical activation in the olfactory, frontal, and somatosensory cortices by functional near-infrared spectroscopy, and analyzed pain behaviors from videotaped recordings. Newborns integrated trigeminal/olfactory stimuli in trigeminal/olfactory and nociceptive processing areas beginning at 31 weeks postmenstrual age, and also exhibited pain behaviors. Pain scores were positively associated with the level of cortical activation. Oral glucose inhibited pain behaviors and cortical activation. There were developmental differences in cortical integration related to brain maturation and duration of the extra-uterine experience. In conclusion, VPT and FT infants showed trigeminal sensitivity after exposure to alien odors that induce pain, potentially affecting the wiring of the neuronal circuits of the newborn brain.

Background Administration of local anesthetics by a surgically placed wound catheter has recently been shown to reduce the need for postoperative morphine administration in extremely preterm infants undergoing ductus ligation. The primary aim of this randomized safety study was to define the plasma levels of levobupivacaine ( LB) following two different intermittent infusion regimens. Methods Eighteen preterm infants 23-27 gestational weeks, median birthweight 721 g scheduled for ductus ligation were included in the study. All patients were anesthetized according to a standardized protocol based on high-dose fentanyl (25-50 μg·kg−1). Before skin closure, a subcutaneous catheter was inserted into the wound. The patients were randomized to receive one of the two intermittent infusion regimens: Group BII: Initial bolus plus early start of the intermittent infusion or Group DII: No bolus plus delayed start (8 h) of the intermittent infusion. Blood samples for determination of LB plasma concentrations were obtained on six occasions during the 24-h postoperative observation period, as well as hourly postoperative pain assessments using the Echelle Douleur Inconfort Noveau ( EDIN) pain scale. Results Plasma concentrations of LB ranged from 0.094 to 1.682 μg·ml−1 and 0 to 0.549 μg·ml−1 in group BII and DII, respectively. Both regimens were associated with low postoperative EDIN pain scores (24 h median of 0 and 1 in group BII and DII, respectively). No signs of systemic local anesthetic toxicity were noted. Conclusions The two studied intermittent infusion regimens were associated with plasma levels below potentially toxic levels and were both associated with adequate postoperative pain scores. [ABSTRACT FROM AUTHOR]

Background: Opioids are common drugs for pain treatment in preterm newborn infants, in spite of several adverse effects. Constipation is a frequent problem when opioids are used in both adults and neonates. Although several studies indicate that the oral administration of naloxone hydrochloride (NH) improves intestinal motility during opioid therapy, there is still a lack of evidence in newborns. Aim: The aim of this study was to assess the efficacy of NH against reduced intestinal motility during opioid treatment. Methods: A retrospective cohort study was performed. We analysed the medical records of fifteen infants (Group 1) treated with continuous morphine (MO) infusion and fourteen infants (Group 2) treated with both oral NH (3 μg/kg 4 times daily) and MO. Results: There was no statistically significant difference in the total MO dose. Infants treated both with NH and MO had a tendency to improve their mean stool frequency/day. A statistically significant improvement was observed in the mean total food intake (mL/kg/day) of the infants treated with NH (p = 0.014). No difference in the mean food retention between the two groups was observed. Conclusion: Orally administrated NH seems to improve intestinal motility resulting in increased food intake/day and improved stool frequency/day in premature newborn infants treated with MO. Further studies are needed to corroborate these findings. [ABSTRACT FROM AUTHOR]

Abstract: To study the patterns of supraspinal pain processing in neonates, we hypothesized that acute pain causes haemodynamic changes associated with activation of the primary somatosensory cortex. Forty preterm neonates at 28–36 weeks of gestation (mean=32.0) and at 25–42h (mean=30.7) of age were studied following standardized tactile (skin disinfection) and painful (venipuncture) stimuli. Changes in regional cerebral haemodynamics were monitored by near infrared spectroscopy (NIRS) over both somatosensory cortices in 29 newborns, and over the contralateral somatosensory and occipital areas in 11 newborns. Heart rate (HR) and peripheral oxygen saturation (SaO2) were recorded simultaneously with NIRS parameters: oxygenated [HbO2], deoxygenated, and total hemoglobin. Tactile stimulation produced no changes in HR or SaO2. HR increased in the first 20s (p <0.001), while SaO2 decreased during the 40s after venipuncture (p <0.0001). Following tactile or painful stimulation, [HbO2] increased bilaterally regardless of which hand was stimulated (p <0.0001). Pain-induced [HbO2] increases in the contralateral somatosensory cortex (p <0.05) were not mirrored in the occipital cortex (p >0.1). Pain-related [HbO2] increases were more pronounced in male neonates (p <0.05 on left, p <0.001 on right), inversely correlated with gestational age (r =−0.53 on left, p <0.01; r =−0.42 on right, p <0.05) and directly correlated with postnatal age (r =0.75 on left, p <0.0001; r =0.67 on right, p <0.0001). Painful and tactile stimuli elicit specific haemodynamic responses in the somatosensory cortex, implying conscious sensory perception in preterm neonates. Somatosensory cortical activation occurs bilaterally following unilateral stimulation and these changes are more pronounced in male neonates or preterm neonates at lower gestational ages. [Copyright &y& Elsevier]