The seven individuals in the study had experienced endotracheal intubation at the hospital due to their being in a state of cardiopulmonary arrest. The medical treatment included the use of Xylocaine jelly, a 2-percent lidocaine hydrochloride preparation, before the individuals were pronounced dead. No restoration of heartbeat occurred during cardiopulmonary resuscitation in the first four cases. However, these individuals had systemic distribution of intubation-related lidocaine, and the kidney-to-liver ratios of lidocaine were less than one. Cases Five and Six experienced temporary resumption of the heartbeat with cardiac massage; a kidney-to-liver ratio of lidocaine was greater than one. The seventh case involved an individual who was comatose on admission to the hospital; the kidney-to-liver ratio was also greater than one. Animal experiments substantiated these phenomena. Findings indicated that the absorption of tracheal lidocaine during the artificial circulation resulting from cardiopulmonary resuscitation results in a kidney-to-liver ratio of less than one, whereas absorption during natural circulation gives a ratio greater than one. Findings suggested that the kidney-to-liver ratio of intubation-related lidocaine may give useful information on the status of an individual during cardiopulmonary resuscitation. Tables and 10 references (Author abstract modified)