title: Vagus nerve stimulation improves coagulopathy in hemorrhagic shock: a thromboelastometric animal model study.
abstract: BACKGROUND
  Inflammation plays a major role in the multifactorial process of trauma associated coagulopathy. The vagus nerve regulates the cholinergic anti-inflammatory pathway. We hypothesized that efferent vagus nerve stimulation (VNS) can improve coagulopathy by modulating the inflammatory response to hemorrhage.
  
  
  METHODS
  Wistar rats (n = 24) were divided in 3 groups: Group (G1) Sham hemorrhagic shock (HS); (G2) HS w/o VNS; (G3) HS followed by division of the vagus nerves and VNS of the distal stumps. Hemorrhage (45% of baseline MAPx15 minutes) was followed by normotensive resuscitation with LR. Vagus nerves were stimulated (3.5 mA, 5 Hz) for 30 sec 7 times. Samples were obtained at baseline and at 60 minutes for thromboelastometry (Rotem®) and cytokine assays (IL-1 and IL-10). ANOVA was used for statistical analysis; significance was set at p < 0.05.
  
  
  RESULTS
  Maximum clot firmness (MCF) significantly decreased in G2 after HS (71.5 ± 1.5 vs. 64 ± 1.6) (p < 0.05). MCF significantly increased in G3 compared to baseline (67.3 ± 2.7 vs. 71.5 ± 1.2) (p < 0.05). G3 also showed significant improvement in Alfa angle, and Clot Formation Time (CFT) compared to baseline. IL-1 increased significantly in group 2 and decrease in group 3, while IL-10 increased in group 3 (p < 0.05).
  
  
  CONCLUSIONS
  Electrical stimulation of efferent vagus nerves, during resuscitation (G3), decreases inflammatory response to hemorrhage and improves coagulation.
authors.affiliation: Department of General Surgery, St. Michael's Hospital - University of Toronto, Toronto, ON, Canada.
authors.forename: Joao B
authors.initials: JB
authors.lastname: Rezende-Neto
authors.affiliation: Federal University of Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Roger Lage
authors.initials: RL
authors.lastname: Alves
authors.affiliation: Federal University of Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Mario
authors.initials: M
authors.lastname: Carvalho
authors.affiliation: Federal University of Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Thiago
authors.initials: T
authors.lastname: Almeida
authors.affiliation: Federal University of Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Cyntia
authors.initials: C
authors.lastname: Trant
authors.affiliation: Federal University of Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Christopher
authors.initials: C
authors.lastname: Kushmerick
authors.affiliation: Federal University of Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Marcus
authors.initials: M
authors.lastname: Andrade
authors.affiliation: Department of General Surgery, St. Michael's Hospital - University of Toronto, Toronto, ON, Canada.
authors.forename: Sandro B
authors.initials: SB
authors.lastname: Rizoli
authors.affiliation: Federal University of Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Jose
authors.initials: J
authors.lastname: Cunha-Melo
keywords: Coagulopathy; Cytokines; Hemorrhage; Resuscitation; Shock; Thromboelastometry; Trauma; Vagal nerve