THE LACK OF CEREBRAL EFFECTS OF d -TUBOCUARINE

Abstract

A total dose of 500 units of d-tubocurarine chloride was administered intraven. to a healthy 34-yr. old over a period of 33 mins. EEG., ECG., pulse rate, blood pressure, respiratory rate and character, neurologic signs, psychologic indices, and sensorium were observed almost continuously. When verbal contact with the patient was lost, communication was maintained by means of prearranged signals. After paralysis became complete, the exptl. subject took mental notes, which were dictated to a stenographer immediately on recovery of speech. O2 was administered, and artificial respiration with positive pressure O2 was used when respiratory embarrassment developed. Tracheal intubation was performed for a 6-min. period at the height of the paralysis. Nasal and oropharyngeal suction was performed as needed. Despite the complete muscular paralysis, the subject remained acutely conscious, and his memory was unimpaired throughout the expt. Visual acuity, color sense, hearing, and smell did not deteriorate. Cutaneous sensation remained normal. Tracheal intubation caused much less discomfort than anticipated. "Shortness of breath" and choking existed at certain times, despite adequate pulmonary ventilation and oxygenation. No EEG. or ECG. changes were observed in the course of the expt. Artificial respiration, at the rate of 24/min. with smooth expiration, proved to be the most satisfactory subjectively. Complete respiratory paralysis occurred after 200 units of d-tubocurarine were administered (2.5 units/kg.). Three 100-unit doses were injected rapidly within 12 mins. after the development of complete respiratory paralysis. Seven 0.5 mg. doses of neostigmine methylsulfate were injected intraven. over a period of 102 mins. to facilitate recovery. The exptl. findings indicated that d-tubocurarine chloride does not possess central stimulant, depressant, or analgesic properties.