title: Mechanical ventilation is the determining factor in inducing an inflammatory response in a hemorrhagic shock model.
abstract: BACKGROUND
  Hemorrhagic shock (HS) is known to induce an inflammatory response by activating the immune system. This response is mainly caused by primed polymorphonuclear granulocytes (PMNs). Trauma patients often require mechanical ventilation (MV), which can cause additional pulmonary and systemic inflammation. The aim of this study was to evaluate the role of MV in the development of systemic and pulmonary inflammation in a HS model in rats.
  
  
  METHODS
  In male Sprague-Dawley rats, the effect of MV and HS on the systemic and pulmonary inflammatory responses was measured and compared. In five groups (control, sham, MV, HS, and MV + HS), the inflammation was measured at time point 300 min after the start of the experiment.
  
  
  RESULTS
  The systemic inflammatory response, expressed in absolute numbers of PMNs in blood and blood growth related oncogene (GRO-KC) levels, was significantly higher in MV rats compared with that in other groups. The pulmonary inflammatory response, expressed by PMNs in bronchoalveolar lavage fluid (BALF), BALF interleukin 6, BALF GRO-KC, and myeloperoxidase activity, was significantly higher in all ventilated rats compared with that in the controls or HS rats. There was, however, no additional effect of HS in MV as the inflammatory indices were similar in both groups.
  
  
  CONCLUSIONS
  Our data show that HS alone has minimal effect on the development of inflammation. MV (alone or in combination with HS) is the determining factor in inducing an inflammatory response. These results emphasize the importance of local (pulmonary) ventilation-induced damage in the development of systemic inflammation.
authors.affiliation: Department of Trauma Surgery, University Medical Center Utrecht, Utrecht, The Netherlands. kwessem@umcutrecht.nl
authors.forename: Karlijn J P
authors.initials: KJ
authors.lastname: van Wessem
authors.forename: Marije P
authors.initials: MP
authors.lastname: Hennus
authors.forename: Marjolein
authors.initials: M
authors.lastname: Heeres
authors.forename: Leo
authors.initials: L
authors.lastname: Koenderman
authors.forename: Luke P H
authors.initials: LP
authors.lastname: Leenen
mesh_terms: D000818:Animals; D007249:Inflammation / Q000209:etiology*; D008297:Male; D009504:Neutrophils / Q000502:physiology; D011014:Pneumonia / Q000209:etiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012121:Respiration, Artificial / Q000009:adverse effects*; D012771:Shock, Hemorrhagic / Q000150:complications*