Georges Teyssier

Autonomic nervous system activity in premature and full-term infants from theoretical term to 7 years

The premature population reaching theoretical term suffers from a major deficit in autonomic nervous system (ANS) activity, as can be seen from heart rate variability indices. Whether this autonomic function recovers in the long term is not yet established. Thus, we analyzed and compared ANS activity indices, at birth or at the time of the theoretical term, and at ages 2-3 and 6-7 years, in two populations: a group of 30 premature children and a reference group of 14 full-term age-matched newborns. Using Fourier Transform analysis, we studied 24-h ECG Holter recordings to establish heart rate variability indices: Ptot, VLF, LF, HF, ratio LF/HF, LFnu, HFnu. In the neonatal period, sympathetic and even more markedly, parasympathetic activities were very low in prematures compared to the reference full-term group. At ages 2-3 and 6-7 years, prematures had recovered and had similar ANS activity as the full-term group. These data suggest a fast ANS maturation in prematures during the two first years of life, with a higher speed of recovery for the parasympathetic arm. Furthermore, compared evolution shows a faster ANS maturation in premature. Potential mechanisms are discussed.

Autonomic cardiac control of very preterm newborns: A prolonged dysfunction

BACKGROUND Autonomic nervous system (ANS) activity is fundamental to infant health. ANS activity of preterm newborns seems to be reduced at term equivalent age, but follow-up of ANS activity has rarely been performed in that population during the weeks after birth. The aim of the study was to perform such a follow-up in preterm newborns of different gestational ages, up to their term equivalent ages. METHODS Prolonged electrocardiographic recordings were prospectively performed in a group of 39 premature newborns, each week, up to term equivalent age before discharge. Control values were obtained from a group of 19 full-term newborns, recorded at the first week of their life. ANS indices were calculated from recordings during quiet sleep periods by spectral-domain analysis (Fourier transform): Ptot (total power), VLF (very low-frequencies), LF (low-frequencies), HF (high-frequencies), LF/HF ratio, LFnu (normalized low-frequencies) and HFnu (normalized high-frequencies) values. RESULTS Ptot, VLF, LF and HF were significantly lower in the preterm group at birth compared to the control group, while LFnu, HFnu and LF/HF ratio were not significantly different. The results were similar when comparing the control group to any ANS values at a given post-natal corrected age of preterm newborns. Furthermore, preterm newborns did not demonstrate any significant increase in ANS values from birth to theoretical term. CONCLUSION The finding of substantial reduced ANS activity and failure of maturation in preterm infants up to term equivalent age needs confirming by other research groups, and mechanisms and implications for infant health explored.

Birth prematurity determines prolonged autonomic nervous system immaturity.

Because of its multiple involvement in physiological processes, autonomic nervous system (ANS) activity, a key regulator of homeostatic control, demonstrates a progressive increase during pregnancy. The profile of its maturation, mainly in the parasympathetic arm, in premature or full term infants, may help us to better understand its pathophysiological role. We prospectively evaluated ANS maturity in a group of 23 premature (PREM) infants at their theoretical term age and in 8 full term (FT) newborns. All recordings were registered close to the theoretical full term period (from 38 to 41 weeks) for the PREM group and during the first week of life for the FT newborns. Polygraphic recordings, EEG monitoring associated with visual clinical control, and Holter ECG, were performed simultaneously. ANS indices were then calculated during quiet sleep periods, using Wavelet transform of RR (beat to beat) intervals. High frequency components were found to be significantly lower in the PREM than in the FT group (p<0.05). Furthermore, at theoretical full term age, the greater the prematurity, the lower was parasympathetic activity. Because it is easy, monitoring of parasympathetic activity may help us to understand autonomic maturation and its clinical prognostic implications.

Implication of a healthcare worker with chronic skin disease in the transmission of an epidemic strain of methicillin-resistant Staphylococcus aureus in a pediatric intensive care unit.

This outbreak of colonization of neonates in a 10-bed pediatric intensive care unit illustrates the probable role of a healthcare worker (HCW) in the transmission of methicillin-resistant Staphylococcus aureus, despite good hygienic practices. It raises the issue of preventive exclusion of HCWs affected by chronic skin disease from high-risk units.

Autonomic dysfunction with early respiratory syncytial virus-related infection.

BACKGROUND Apparent life-threatening events (ALTE) and/or prolonged apnoea have been well-documented during respiratory syncytial virus (RSV) infection in infants less than 2 months of age but fundamental mechanisms remain unclear. The possibility of a central origin for the development of severe cardiac and respiratory events encouraged us, to explore the autonomic nervous system (ANS) profile of infected infants, since ANS activity may contribute to the constellation of symptoms observed during severe forms of RSV bronchiolitis. METHODS Eight infants (2 preterm and 6 full-term) less than 2 months of age and presenting with severe and apnoeic forms of RSV infection were evaluated using non-invasive electrophysiological monitoring obtained simultaneously for approximately 2 consecutive hours, including a quiet sleep period. Eight control subjects, paired for gestational and postnatal age, were also evaluated. ANS status was monitored using electrocardiogram recordings and quantified through a frequency-domain analysis of heart rate variability (HRV). This included sympathetic (VLF and LF) and parasympathetic (HF) indices as well as a measure of baroreflex sensitivity (BRS) obtained using non-invasive continuous arterial pressure. RESULTS Regardless of gestational and postnatal age, heart rate variability components (Ptot, VLF, LF, and HF) and baroreflex components (alpha LF, alpha HF and sBR) were found to be significantly lower in the RSV-infected group than in the control group (p<0.05). CONCLUSION RSV infection in neonates is associated with profound central autonomic dysfunction. The potentially fatal consequence stresses the importance of maintaining prolonged cardiopulmonary monitoring.

Reported measures of hygiene and incidence rates for hospital-acquired diarrhea in 31 French pediatric wards: is there any relationship?

OBJECTIVE To investigate the relationship between hygienic measures reported for the prevention of hospital-acquired diarrhea and incidence rates of hospital-acquired diarrhea. DESIGN A survey of hospital-acquired diarrhea was conducted between January 1 and March 31, 1999. Multivariate analysis of reported measures of hygiene according to the observed incidence rates of hospital-acquired diarrhea was performed. SETTING Thirty-one pediatric or neonatal wards located in hospitals in the southeast of France, selected as a convenience sample of wards volunteering to participate. PATIENTS A total of 6,726 children younger than 5 years. RESULTS The overall incidence rate of hospital-acquired diarrhea was 3.6%. Rotavirus was responsible for 69% of the cases of hospital-acquired diarrhea. Among the hygienic measures reported by the wards for preventing hospital-acquired diarrhea were using a single room or cohorting (77.4%), washing hands (83.9%), wearing gowns (80.6%), and wearing disposable single-use gloves for diapering a patient (51.6%). By multivariate analysis, the variables statistically associated with a lower incidence of hospital-acquired diarrhea were restricting the patients mobility outside his or her room, keeping the patients door closed, and having fewer than 20 beds in the ward, with adjusted odds ratios of 0.34 (95% confidence interval [CI95], 0.18 to 0.65), 0.33 (CI95, 0.23 to 0.47), and 0.42 (CI95 0.30 to 0.60), respectively. CONCLUSION Simple preventive measures can decrease the rate of hospital-acquired diarrhea in pediatric wards.

Infant botulism intoxication and autonomic nervous system dysfunction

Three infants presenting with severe cases of infantile botulism, occurring at 17, 30, and 180 days of life, respectively, are described in this report. All three infants presented with areflexive flaccid coma or apnoeas requiring prolonged ventilation. In serum, type B botulinum neurotoxin (BoNT/B) was detected in two cases and BoNT/A in the third case, confirming the diagnosis of infantile botulism. Despite constant nursing and monitoring, the recovery of motility was progressive, but finally complete. Dysautonomia, measured by recording heart rate variability (HRV), persisted beyond observable physical recovery. Dysautonomia was assessed using a time-domain analysis of the continuous electrocardiogram response (via non-invasive weekly 24h Holters), which included sympathetic (SDNN) and parasympathetic indices (RMS-SD, pNN50). In all three of our patients, we observed an initial hypotonic period and a major decrease in all HRV indices. Despite observable recovery shortly after extubation, HRV time domain indices remained altered for many weeks. Because of the close monitoring afforded by hospitalization, this change in autonomic function was not accompanied by syncope, complications arising from ventricular arrhythmia, or sudden death. Our observations have important clinical implications since they emphasize the importance of pursuing cardiopulmonary monitoring following apparent functional recovery from the BoNTs.

Congenital Diaphragmatic Hernia

The early ultrasound prenatal diagnosis of congenital diaphragmatic hernia is uncommon and suggests a poor outcome. We report 2 cases diagnosed at 10 and 12 weeks’ gestation, with increased fetal nuchal translucency thickness (4 and 11 mm) and associated abnormalities (complex heart defect in one and many malformations in the other, including duodenal atresia and asplenia). In 1 case, the baby was delivered vaginally at 36 weeks, but neonatal death occurred; the pregnancy was terminated at 15 weeks in the second case.

Severe cutaneous aspergillosis in a premature neonate linked to nonsterile disposable glove contamination

After having eliminated a dysfunction of the hospitals ventilation system and any other possible environmental reservoir, the investigation of a fatal case of primary cutaneous aspergillosis in a neonate with extremely low birth weight led to the conclusion that nonsterile disposable gloves kept stored in their native packages were the likely source of contamination.

Autonomic dysfunction in 2009 pandemic influenza A (H1N1) virus-related infection: a pediatric comparative study.

BACKGROUND Relationship between respiratory morbidity and influenza virus has been well-documented in infants, whatever their age. However, in spite of severe cardiac and respiratory events of central origin, autonomic dysfunction potentially induced by this virus is poorly understood. We thus explored the autonomic nervous system (ANS) profile of infected infants during the 2009 pandemic influenza disease. METHOD A group of 10 consecutive infants (5<1 year and 5>1 year) presenting with nvH1N1 infection was evaluated with heart rate variability (HRV) and spontaneous baroreflex (SBR) through a recording during a 15-minute period of quiet sleep as well as 24h holter monitoring. The same recordings were performed in 10 control subjects, paired for gestational and postnatal age. HRV sympathetic and parasympathetic (VLF, LF and HF) indices were obtained using spectral-domain analysis, and spontaneous baroreflex sensitivity (SBR) using simultaneous non-invasive continuous measure of arterial pressure and heart rate. RESULTS The group of infants less than 1 year had similar value as control group. Conversely, the group of infants more than 1 year showed significant lower spectral total power values (Ptot: 3347 vs. 5926 ms(2)/Hz, p<0.1) and significant lower VLF, LF and HF indices (all p<0.05) than the control group. CONCLUSION nvH1N1 infection in child could be associated with severe central autonomic dysfunction. Due to potential severe consequences, a systematic evaluation of autonomic regulation should be performed in order to avoid dramatic events.