Methods: A prospective randomized animal study was performed
using 27 domestic pigs (body weight, 30 to 35 kg). Pentobarbitalanesthetized
pigs were assigned to receive one of three treatments:
(1) chest compression without assisted ventilation (n=8),
(2) assisted ventilation with room air (n=8), and (3) assisted ventilation
with 100% oxygen (n=8). A fourth group, with the airway
completely blocked, was added at the end of the experiment
(n=3). After instrumentation, the ventricles were fibrillated, and
chest compression was begun 30 seconds after fibrillation with
the use of the Thumper Mechanical CPR system (Michigan Instruments).
Arterial and mixed venous blood gas samples were collected
at 1, 3, 10, and 20 minutes of resuscitation. Defibrillation
was attempted after the 20-minute sample was taken.
Results: Fibrillation followed by chest compression alone