title: Post-operative pressure lability and cardiac baroreflex in normotensive patients as a function of age.
abstract: BACKGROUND
  Pressure lability may be linked to the loss of the cardiac baroreflex. The reduction of the sensitivity of the cardiac baroreflex has not been delineated in the post-operative period according to age in normotensive patients. This study addresses pressure lability and slope of the cardiac baroreflex as a function of age.
  
  
  METHODS
  Patients were allocated to the following three groups: young (20-39 years, n=7), middle aged (40-59 years, n=7) and elderly (60-79 years, n=6), and studied before minor intra-abdominal surgery under CO(2) peritoneal insufflation and nitrous oxide-isoflurane-sufentanil anesthesia, up to 24 h after extubation. An electrocardiogram and non-invasive beat-by-beat pressure monitoring (Finapres) allowed offline calculation of the sensitivity of the cardiac baroreflex ('sequence' technique) and standard deviation (SD) of heart rate (HR; HR variability) and systolic blood pressure (SBP; pressure lability).
  
  
  RESULTS
  Before anesthesia, (a) an inverse relationship was observed between the slope of the cardiac baroreflex and age and (b) a trend (P<0.09) existed between the slope of the cardiac baroreflex and pressure lability, irrespective of age. During the early post-operative period, young patients returned to their baseline slope of the cardiac baroreflex; no inverse relationship between increased SD of SBP and decreased SD of RR interval was observed. Middle-aged and elderly patients displayed a depressed slope of the cardiac baroreflex both before and after anesthesia.
  
  
  CONCLUSIONS
  At variance with the pre-operative period, no simple inverse relationship was observed between increased pressure lability and depressed HR variability in young patients during the early post-operative period.
authors.affiliation: Department of Physiology (CNRS UMR 5123), Hopital E Herriot, University Lyon, Lyon, France.
authors.forename: A
authors.initials: A
authors.lastname: Cividjian
authors.forename: V
authors.initials: V
authors.lastname: Meyrieux
authors.forename: P
authors.initials: P
authors.lastname: Gratadour
authors.forename: P
authors.initials: P
authors.lastname: Sagnard
authors.forename: G
authors.initials: G
authors.lastname: Annat
authors.forename: J
authors.initials: J
authors.lastname: Boulez
authors.forename: J P
authors.initials: JP
authors.lastname: Viale
authors.forename: L
authors.initials: L
authors.lastname: Quintin
mesh_terms: D000328:Adult; D000368:Aged; D017704:Baroreflex; D001794:Blood Pressure; D002319:Cardiovascular System / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000503:physiopathology*; D016896:Treatment Outcome