title: Tetramethylammonium ion causes respiratory failure related mortality in a rat model.
abstract: OBJECTIVE
  Tetramethylammonium ion (TMA) is an emerging industrial chemical and has caused mortalities in humans. The present study was conducted to evaluate the effects of subcutaneously injected TMA on heart rate (HR), mean arterial blood pressure (MAP) and arterial blood gases (ABG) and to determine whether pretreatment using mechanical ventilation (MV) or atropine could prevent the mortality caused by TMA.
  
  
  METHODS
  Male Wistar rats were anesthetized and catheterized in the femoral arterials for monitoring. We injected 25, 50, 100, and 200 μmol/kg of TMA s.c. in four groups of rats respectively and compared them to a control group. The effects of MV and atropine (1mg/kg, s.c.) pretreatment were evaluated by comparing the treatment groups with the 200 μmol/kg group. The primary outcome was survival curve, and the secondary endpoints included the changes of HR, MAP, and ABG, such as arterial pH, PaO(2), PaCO(2) and calculated HCO(3)(-).
  
  
  RESULTS
  TMA decreased HR, MAP, pH, and PaO(2), increased PaCO(2) and calculated HCO(3)(-) and resulted in death of all animals in the 200 μmol/kg group by 15 min. All animals pretreated with MV survived. Although all animals receiving atropine died, the mean survival time increased by 37 min. Both MV and atropinization improved HR, MAP, and ABG.
  
  
  CONCLUSIONS
  This rat model suggests that acute respiratory failure is responsible for the mortality caused by TMA, and therefore first aid should emphasize respiratory support. Atropinization prolonged survival time in the present study that possibly bought time for further management.
authors.affiliation: Department of Environmental and Occupational Health, College of Medicine, National Cheng Kung University, 138 Sheng-Li Road, Tainan, Taiwan.
authors.forename: Chen-Long
authors.initials: CL
authors.lastname: Wu
authors.forename: Shih-Bin
authors.initials: SB
authors.lastname: Su
authors.forename: Jin-Luh
authors.initials: JL
authors.lastname: Chen
authors.forename: Cheng-Ping
authors.initials: CP
authors.lastname: Chang
authors.forename: How-Ran
authors.initials: HR
authors.lastname: Guo
mesh_terms: D000085:Acetates / Q000633:toxicity*; D000818:Animals; D001285:Atropine / Q000627:therapeutic use*; D002423:Cause of Death / Q000639:trends; D004195:Disease Models, Animal; D005731:Ganglionic Stimulants / Q000633:toxicity; D008297:Male; D010276:Parasympatholytics / Q000627:therapeutic use; D011379:Prognosis; D000644:Quaternary Ammonium Compounds / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D012121:Respiration, Artificial / Q000379:methods*; D012131:Respiratory Insufficiency / Q000139:chemically induced / Q000401:mortality* / Q000628:therapy; D015996:Survival Rate / Q000639:trends
chemical_list: D000085:Acetates; D005731:Ganglionic Stimulants; D010276:Parasympatholytics; D000644:Quaternary Ammonium Compounds; C409669:tetramethylammonium hydrogen bis(difluorochloroacetate); D001285:Atropine