Tucker et al,1 in their article entitled "Cardiopulmonary Resuscitation: Historical Perspectives, Physiology, and Future Directions" in the October 10,1994, issue of the Archives, reviewed the two physiologic theories that have been proposed to explain the mechanisms of blood flow during cardiopulmonary resuscitation (CPR): the direct cardiac compression and thoracic pump models. They concluded that both mechanisms "... are not necessarily mutually exclusive" and that "... both mechanisms may be operant,"1 sentiments with which my coworkers and I agree.
However, we take strong issue with the authors' concluding statement in the "Thoracic Pump Model" section: "... the thoracic pump model provides no mechanism at all for blood flow to the coronary circulation."1 This claim is later contradicted by their own text in the "Vest CPR" section, in which they cite "... improved coronary perfusion and survival" and "... coronary flow of 40% to 60% of normal" in dogs and