title: The role of autonomic nervous system function in hypothermia-mediated sepsis protection.
abstract: OBJECTIVE
  The objective of this study is to determine whether hypothermia will lessen decreases in heart rate variability and improve outcome in a rat model of sepsis.
  
  
  METHODS
  Thirty-six male Sprague-Dawley rats were randomized into 3 groups: control, low sepsis, and high sepsis groups. These groups were each subdivided into a normothermia (37°C) (n = 6) and a hypothermia group (34°C) (n = 6). Cyclophosphamide (100 mg/kg) was administered 5 days before Staphylococcus aureus injection to produce conditions in which sepsis could be induced reliably. Hypothermic rats received temperature reduction for 1 hour post injection. Electrocardiogram was recorded before, after, and 1 day after staphylococcal injection, and the low frequency, high frequency (HF), and LF/HF ratio measurements of heart rate variability and the frequencies of arrhythmia were recorded. The effects of time, sepsis severity, and hypothermia on these variables were analyzed using a multivariate generalized estimation equation mode.
  
  
  RESULTS
  Four deaths occurred in the normothermic group, and none, in the hypothermic group. Sepsis of both low and high severity increased low frequency and HF 1 day after sepsis induction. Hypothermia significantly decreased HF in low, but not high sepsis severity.
  
  
  CONCLUSIONS
  Hypothermia decreased mortality in septic rats. The influence of hypothermia on HF depended on the severity of the sepsis.
authors.affiliation: Department of Emergency Medicine, Kaohsiung Veterans General Hospital, Kaohsiung City 81362, Taiwan, ROC.
authors.forename: Yun-Te
authors.initials: YT
authors.lastname: Chang
authors.forename: Shue-Ren
authors.initials: SR
authors.lastname: Wann
authors.forename: Jung-Shun
authors.initials: JS
authors.lastname: Tsai
authors.forename: Chih-Hsiang
authors.initials: CH
authors.lastname: Kao
authors.forename: Po-Tsang
authors.initials: PT
authors.lastname: Lee
authors.forename: Neng-Chyan
authors.initials: NC
authors.lastname: Huang
authors.forename: Cheng-Chang
authors.initials: CC
authors.lastname: Yen
authors.forename: Mu-Shun
authors.initials: MS
authors.lastname: Huang
authors.forename: Hong-Tai
authors.initials: HT
authors.lastname: Chang
mesh_terms: D000818:Animals; D001341:Autonomic Nervous System / Q000502:physiology*; D004195:Disease Models, Animal; D004562:Electrocardiography; D006339:Heart Rate / Q000502:physiology*; D007036:Hypothermia, Induced; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D018805:Sepsis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D012720:Severity of Illness Index; D013203:Staphylococcal Infections / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*