title: Still making the case against prehospital intubation: a rat hemorrhagic shock model.
abstract: BACKGROUND
  Prehospital intubation does not appear to result in a survival advantage for patients experiencing penetrating trauma; yet, there is still resistance to the practice of "scoop and run" to speed access to advanced care. An animal model was used to determine whether intubation provides a survival advantage during potentially lethal hemorrhage.
  
  
  METHODS
  The carotid arteries of Sprague-Dawley rats were cannulated, and mean arterial pressure (MAP) was measured. One group of animals (n = 10) was intubated and placed on a ventilator, whereas the other (n = 9) was administered with 100% oxygen via nose cone. Rats were exsanguinated to a MAP of 40 mm Hg and then bled periodically to maintain a MAP between 40 mm Hg and 45 mm Hg. The primary end-point was time until death. Secondary end-points included lactic acid and base excess levels measured in blood collected at 30-minute intervals after inducing shock.
  
  
  RESULTS
  There was no significant difference in time until death between the intubated and nose cone groups (85.5 vs. 93.3 minutes, p = 0.60). Intubated animals had higher lactic acid levels at 90 minutes (6.1 vs. 3.5 mmol/L; p = 0.02) and 120 minutes (7.7 vs. 2.6 mmol/L, p = 0.03) after the initiation of shock. In addition, intubated animals had worse base excess at 90 minutes (-13.5 vs. -7.9 mmol/L, p = 0.04).
  
  
  CONCLUSIONS
  Intubation does not result in a survival advantage in this rat model of hemorrhagic shock. Positive pressure ventilation may cause decreased venous return and accentuate end-organ hypoperfusion. Large animal studies are needed to further investigate these findings.
authors: Department of Surgery, Temple University Hospital, Philadelphia, Pennsylvania 19140, USA.
authors: Sharven
authors: S
authors: Taghavi
authors: Jason M
authors: JM
authors: Duran
authors: Senthil
authors: S
authors: Jayarajan
authors: Gonzalo E
authors: GE
authors: Cruz-Schiavone
authors: Richard E
authors: RE
authors: Milner
authors: John P
authors: JP
authors: Gaughan
authors: Lars O
authors: LO
authors: Sjoholm
authors: Abhijit
authors: A
authors: Pathak
authors: Thomas A
authors: TA
authors: Santora
authors: Steven R
authors: SR
authors: Houser
authors: Amy J
authors: AJ
authors: Goldberg
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001774:Blood Chemical Analysis; D002423:Cause of Death; D004195:Disease Models, Animal; D004632:Emergency Medical Services / Q000592:standards / Q000639:trends; D006801:Humans; D007442:Intubation, Intratracheal / Q000379:methods*; D053208:Kaplan-Meier Estimate; D008297:Male; D011175:Positive-Pressure Respiration / Q000379:methods; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D018570:Risk Assessment; D012771:Shock, Hemorrhagic / Q000401:mortality* / Q000628:therapy*; D015996:Survival Rate; D014950:Wounds, Penetrating / Q000401:mortality / Q000628:therapy