Difference in Acid-Base State between Venous and Arterial Blood during Cardiopulmonary Resuscitation

To the Editor: The marked elevation in mixed venous partial pressure of carbon dioxide (PCO 2 ) found during cardiopulmonary resuscitation by Weil and coworkers (July 17 issue) 1 is an intriguing new observation, and clearly requires further studies to delineate its clinical importance. The authors and your accompanying editorial 2 both offer explanations for the high PCO 2 . I am perplexed, however, because no one even raised for consideration what seems to be the most likely cause — abrupt restoration of oxidative metabolism and a resultant surge of carbon dioxide production as tissue oxygen delivery returns. More than 90 percent . . .