Despite these limitations, it is clear that assisted ventilation
can improve the oxygenation of blood and, consequently,
oxygen delivery to the organs during CPR. This
improvement is notable early in the resuscitative period. In
the absence of significant oxygenation4 or during a brief
resuscitation period,16 successful resuscitation is possible.
The important question of the physiologic consequences
of assisted ventilation, particularly during the 10- to 15-
minute interval, must be further evaluated in studies of
survival and neurologic outcome before any change to current
CPR protocols can be recommended.
In the anesthetized pig model, standard chest compression
does not provide physiologically significant pulmonary
ventilation. Our data indicate that assisted ventilation, even
with room air, should improve oxygen delivery to tissues
during resuscitation. Additionally, our findings indicate that
supplementation with inspired oxygen may improve blood
gas values even during an extended period of CPR.