Spontaneous gasping generates cardiac output during cardiac arrest.
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.
Xie
Jing
J
Institute of Critical Care Medicine, Palm Springs, CA, USA.
Weil
Max Harry
MH
Sun
Shijie
S
Yu
Ting
T
Tang
Wanchun
W
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
D002245:Carbon Dioxide