New developments in cardiopulmonary resuscitation
J. M. Luce, J. M. Cary, B. K. Ross, B. H. Culver and J. Butler
The traditional concept of cardiopulmonary resuscitation (CPR) is that the
heart is squeezed between the sternum and the spine during external cardiac
massage to create a pressure gradient that forces blood from the heart to
the periphery. Although the heart may actually be squeezed in some persons
by this maneuver, a newer view of CPR holds that closed-chest compression
produces a generalized rise in intrathoracic pressure that is applied to
the pulmonary vascular bed as well as the heart. Thus, the heart does not
serve primarily as a pump during external cardiac massage but instead acts
as a conduit for blood from the lungs. Furthermore, flow into extrathoracic
vessels depends on their tendency to remain open or to collapse: forward
flow occurs across the head during CPR because a pressure gradient is
developed between the carotid artery and the more compressible jugular
vein. These ideas have potential clinical implications and greatly increase
our understanding of the physiology of CPR.
