title: Spontaneous gasping generates cardiac output during cardiac arrest.
abstract: OBJECTIVE
  To measure stroke volumes coincident with spontaneous gasping during untreated ventricular fibrillation and to evaluate the effects of gasping.
  
  
  METHODS
  Prospective study in laboratory animals.
  
  
  METHODS
  University-affiliated research institute.
  
  
  METHODS
  Male Yorkshire-X domestic pigs.
  
  
  METHODS
  Pigs were anesthetized (ketamine, 20 mg/kg intramuscularly and sodium pentobarbital, 30 mg/kg intravenously), intubated, and mechanically ventilated. Ventricular fibrillation was electrically induced and untreated for 7 mins. The right femoral artery and vein were cannulated. A 5.5/7.5-MHz biplanar transesophageal echocardiography transducer was advanced into the esophagus.
  
  
  RESULTS
  Stroke volumes were measured as the product of the transaortic blood flow velocity and transesophageal echocardiographic measurements of valve area. In addition, left ventricular volumes were echocardiographically estimated at peak inspiration and at peak expiration of each gasp by transesophageal methods. The stroke volume produced by gasping averaged 23 +/- 6 mL, which represented approximately 60% of a precardiac arrest stroke volume (38 +/- 8 mL, p <.001). Increases in end-tidal carbon dioxide tension coincident with each gasp were consistent with comparable increases in pulmonary blood flow and therefore stroke volumes. Both were associated with increases in aortic pressure from 20 +/- 3 to 33 +/- 8 mm Hg (p <.001) and coronary perfusion pressure from 4 +/- 3 to 13 +/- 7 mm Hg (p <.001).
  
  
  CONCLUSIONS
  Our studies confirm that preterminal gasping during ventricular fibrillation increases both ventilation and forward blood flow.
authors.affiliation: Institute of Critical Care Medicine, Palm Springs, CA, USA.
authors.forename: Jing
authors.initials: J
authors.lastname: Xie
authors.forename: Max Harry
authors.initials: MH
authors.lastname: Weil
authors.forename: Shijie
authors.initials: S
authors.lastname: Sun
authors.forename: Ting
authors.initials: T
authors.lastname: Yu
authors.forename: Wanchun
authors.initials: W
authors.lastname: Tang
mesh_terms: D000818:Animals; D002245:Carbon Dioxide / Q000032:analysis*; D002302:Cardiac Output / Q000502:physiology*; D004195:Disease Models, Animal; D017548:Echocardiography, Transesophageal; D004562:Electrocardiography; D006323:Heart Arrest / Q000175:diagnosis / Q000503:physiopathology*; D006439:Hemodynamics / Q000502:physiology*; D008297:Male; D011659:Pulmonary Gas Exchange; D012119:Respiration; D012680:Sensitivity and Specificity; D034421:Sus scrofa; D014693:Ventricular Fibrillation / Q000503:physiopathology
chemical_list: D002245:Carbon Dioxide