ON THE PREVENTION OF THE BLOOD PRESSURE FALL DURING SPINAL ANESTHESIA IN THE RABBIT

¹ From the Department of Pharmacology, the University of Minnesota Medical School, Minneapolis

Six drugs or drug combinations were found which would prevent the severe fall in blood pressure produced by procaine spinal anesthesia in the rabbit. These were: synephrine, synephrine plus pitressin, ephedrine plus pitressin plus metrazol, ephedrine plus pitressin, neosynephrine plus pitressin and neosynephrine plus pitressin plus metrazol. Synephrine was the only drug thus studied which, when used alone, could maintain the systolic blood pressure above 100 mm. Hg in a dose that was not dangerously near the toxic dose. Synephrine was active in either subcutaneous or intravenous administration and did not decrease significantly the duration of anesthesia produced by procaine intraspinally.³