title: Cardiac variability in critically ill adults: influence of sepsis.
abstract: OBJECTIVE
  To evaluate, in critically ill adults, factors associated with impaired sympathovagal balance.
  
  
  METHODS
  One-month inception cohort study.
  
  
  METHODS
  Twenty-six-bed medical intensive care unit of a teaching hospital.
  
  
  METHODS
  Critically ill adults with an expected duration of intensive care unit stay of > or =48 hrs were enrolled. Patients with permanent arrhythmia or cardiac pacing were not included.
  
  
  METHODS
  None.
  
  
  RESULTS
  Sympathovagal balance was assessed on the day after intensive care unit admission by the low-frequency/high-frequency ratio obtained from spectral components of heart rate signal: overall variability, low frequency, and high frequency.
  
  
  RESULTS
  Forty-one patients, 13 with sepsis and 28 without sepsis, were assessed. Predictors of low-frequency/high-frequency ratio with the automatic interaction detection method were sepsis and age. Binary logit analysis adjusted for age showed that sepsis remained a strong and independent factor of a low-frequency/high-frequency ratio of <1.50, with an odds ratio of 3.63 (95% confidence interval, 1.47-9.01, p =.005). Use of mechanical ventilation, catecholamines, or sedation did not add any information. The use of the low-frequency/high-frequency ratio in diagnosing sepsis may be supported by a likelihood ratio for low frequency/high frequency <1 at 6.47.
  
  
  CONCLUSIONS
  This work suggests that impaired cardiac variability and notably sympathovagal balance (i.e., a low-frequency/high-frequency ratio <1.0) may be a diagnostic test for sepsis.
authors.affiliation: Service de Réanimation Médicale, hôpital Raymond Poincaré, Faculté de médecine Paris ouest, Garches, France.
authors.forename: M
authors.initials: M
authors.lastname: Korach
authors.forename: T
authors.initials: T
authors.lastname: Sharshar
authors.forename: I
authors.initials: I
authors.lastname: Jarrin
authors.forename: J P
authors.initials: JP
authors.lastname: Fouillot
authors.forename: J C
authors.initials: JC
authors.lastname: Raphaël
authors.forename: P
authors.initials: P
authors.lastname: Gajdos
authors.forename: D
authors.initials: D
authors.lastname: Annane
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005583:Fourier Analysis; D005602:France / Q000453:epidemiology; D006321:Heart / Q000294:innervation* / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D016013:Likelihood Functions; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D018805:Sepsis / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology*; D012772:Shock, Septic / Q000503:physiopathology; D018709:Statistics, Nonparametric; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D018746:Systemic Inflammatory Response Syndrome / Q000503:physiopathology; D014630:Vagus Nerve / Q000503:physiopathology*