title: Electrical activity of the diaphragm in a small cohort of term neonates.
abstract: BACKGROUND
  Electrical activity of the diaphragm (E(di)) has been proposed as a parameter to evaluate respiratory function. Normative values of electrical activity of the diaphragm in full-term neonates are not known. This is a small case series to establish preliminary values  of E(di) in term neonates and to determine how these values vary while awake and asleep and during feeding states.
  
  
  METHODS
  Three term neonates in room air and nippling feeds at the time of the study were observed for 4 hours. E(di) was measured by electrodes within a nasogastric  tube positioned at the level of the diaphragm. Respiratory rate and heart rate were also recorded. Time while awake and asleep were noted. Feeding states included feeding, 30 min pre-prandial, and 30 min post-prandial. Statistics were analysis of variance and t tests, with P  < .05.
  
  
  RESULTS
  Mean E(di) peak was 11 ± 5 μV. Mean E(di) minimum was 3 ± 2 μV. E(di) peak and minimum were higher while awake. E(di) peak was lower post-prandial. Respiratory rate was higher post-prandial.
  
  
  CONCLUSIONS
  These are the  first preliminary values for E(di) in neonates. Higher E(di) peak while awake may reflect larger tidal volume to meet increased metabolic requirements when awake and active. Post-prandial lower E(di) peak and higher respiratory rate may indicate compensation for  decreased tidal volume from increased intra-abdominal pressure. These data may be useful in identifying respiratory pathology in neonates and monitoring progression toward respiratory health.
authors.affiliation: Department of Neonatology, Toledo Children's Hospital, Toledo, Ohio 43606, USA. howardstein@bex.net
authors.forename: Howard M
authors.initials: HM
authors.lastname: Stein
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Wilmoth
authors.forename: Jill
authors.initials: J
authors.lastname: Burton
mesh_terms: D000704:Analysis of Variance; D003964:Diaphragm / Q000502:physiology*; D004435:Eating / Q000502:physiology; D004594:Electrophysiology; D005260:Female; D006339:Heart Rate; D006801:Humans; D007231:Infant, Newborn / Q000502:physiology*; D019518:Postprandial Period / Q000502:physiology; D011446:Prospective Studies; D012016:Reference Values; D056152:Respiratory Rate; D012890:Sleep / Q000502:physiology; D014851:Wakefulness / Q000502:physiology