title: The numenon and the phenomenon.
abstract: A bolus of 3 mg. of atropine was given intravenously (I.V.) to 123 anesthetized patients. Increases in heart rate were seen in 109 patients (88 percent), while 7 patients (5.7 percent) had decreases and 7 others (5.7 percent) had no change. A mean increase in systolic arterial blood pressure of 14 mm. Hg was noted. A certain pattern in increases in heart rate and systolic blood pressure was observed. Ninety-six percent of the patients under cyclopropane, fluorexene, ether, ketamine, or regional (spinal or epidural) anesthesia had heart-rate increases compared with only 77 to 89 percent of the patients anesthetized with halothane, enflurane, or neuroleptanalgesics. Rise in systolic blood pressure was seen in 40 to 50 percent of the former, but only in 31 to 40 percent of the latter group. The arrhythmias observed were transient A-V junctional tachycardias in three instances and bigeminal rhythm in one patient under cyclopropane anesthesia. The administration of a vagolytic dose of atropine to anesthetized patients appears not to be as arrhythmogenic as previously considered.
mesh_terms: D000776:Anesthesiology / Q000193:education; D003142:Communication; D004336:Drug Antagonism; D004501:Education, Medical; D055590:Electromagnetic Phenomena; D007400:Interprofessional Relations; D014481:United States; D012122:Ventilators, Mechanical