RESPIRATORY PARASYMPATHETIC ACTION OF SOME SHORTER ACTING BARBITURIC ACID DERIVATIVES

¹ From the Division of Surgery, Department of Anesthesia and the Laboratory of Experimental Surgery, New York University College of Medicine

1. In cats, following the intravenous administration of anesthetic doses of various short-acting barbiturates (sodium thioethamyl, sodium amytal, sodium evipal, sodium pentothal, and sodium nembutal), the vocal cords become adducted and the laryngeal reflex becomes hyper-reactive. Coughing is a frequent symptom.

2. Therapeutic doses of adrenalin are effective in relieving these respiratory symptoms but the action is transitory.

3. Ephedrin in therapeutic doses was not sufficiently effective; in larger doses, it relieved the symptoms, but was found to produce dangerous cardiac effects.

4. Neo-synephrin was efficacious in reducing laryngospasm and improving respiration but its other actions seem to contraindicate its use.

5. Cervical vagotomy also relieved the symptoms.

6. The adduction of the vocal cords and the active laryngeal reflex, occurring even under deep barbiturate narcosis, are interpreted as being due to a central vagus stimulating action.

7. It is recommended that medicaments of the atropine group be used before the administration of barbituric acid derivatives in order to prevent obstructive respiratory complications.

8. Treatment of obstructive respiratory symptoms during intravenous barbiturate anesthesia should include tracheal intubation to establish a patent airway.