No assisted ventilation cardiopulmonary resuscitation and 24-hour neurological outcomes in a porcine model of cardiac arrest.
OBJECTIVE
To evaluate the effect of no assisted ventilation cardiopulmonary resuscitation on neurologically intact survival compared with ten positive pressure ventilations/minute cardiopulmonary resuscitation in a pig model of cardiac arrest.


METHODS
Prospective randomized animal study.


METHODS
Animal laboratory.


METHODS
Sixteen female intubated pigs (25.2 +/- 2.1 kg) anesthetized with propofol.


METHODS
: fter 8 mins of untreated ventricular fibrillation, the intubated animals were randomized to 8 mins of continuous chest compressions (100/min) and either no assisted ventilation (n = 9) or 10 positive pressure ventilations/min (Smart Resuscitator Bag with 100% O2 flow at 10 L/min) (n = 7). The primary end point, neurologically intact 24-hr survival, was evaluated using a pig cerebral performance category score by a veterinarian blinded to the cardiopulmonary resuscitation method. MEASUREMENTS, AND MAIN RESULTS: During cardiopulmonary resuscitation, aortic and coronary perfusion pressure were similar between groups but cerebral perfusion pressure was significantly higher in the positive pressure ventilation group (33 +/- 15 vs. 14 +/- 14, p = .04). After 7.5 mins of cardiopulmonary resuscitation, arterial pO2 (mm Hg) and mixed venous O2 saturation (%) were significantly higher in the positive pressure ventilation compared with the no assisted ventilation group (117 +/- 29 and 41 +/- 21 vs. 40 +/- 24 and 10.8 +/- 7; p = .01 for both). Paco2 was significantly lower in the positive pressure ventilation group (48 +/- 10 vs. 77 +/- 26, p = .01). After 24 hrs, four of nine no assisted ventilation pigs were alive with a mean cerebral performance category score of 3 +/- 0 vs. five of seven alive and neurologically intact positive pressure ventilation pigs with a cerebral performance category score of 1 +/- 0.3 (p < .001 for cerebral performance category score).


CONCLUSIONS
No assisted ventilation cardiopulmonary resuscitation results in profound hypoxemia, respiratory acidosis, and significantly worse 24-hr neurologic outcomes compared with positive pressure ventilation cardiopulmonary resuscitation in pigs.
Division of Cardiology, University of Minnesota, Minneapolis, MN, USA.
Demetris
D
Yannopoulos
Timothy
T
Matsuura
Scott
S
McKnite
Noah
N
Goodman
Ahamed
A
Idris
Wanchun
W
Tang
Tom P
TP
Aufderheide
Keith G
KG
Lurie
D000818:Animals; D001784:Blood Gas Analysis; D016887:Cardiopulmonary Resuscitation / Q000379:methods* / Q000401:mortality; D035641:Chest Wall Oscillation / Q000379:methods* / Q000401:mortality; D016009:Chi-Square Distribution; D004195:Disease Models, Animal; D005260:Female; D006323:Heart Arrest / Q000209:etiology / Q000401:mortality / Q000628:therapy*; D000860:Hypoxia / Q000175:diagnosis / Q000453:epidemiology; D015994:Incidence; D009422:Nervous System Diseases / Q000175:diagnosis* / Q000453:epidemiology; D009460:Neurologic Examination; D011175:Positive-Pressure Respiration / Q000379:methods* / Q000401:mortality; D011336:Probability; D011652:Pulmonary Circulation; D011897:Random Allocation; D012016:Reference Values; D012307:Risk Factors; D016019:Survival Analysis; D013552:Swine; D014693:Ventricular Fibrillation / Q000150:complications / Q000628:therapy