A Vasopressor Phenomenon Following Intra-arterial Administration of Hypertonic Solutions

The behavior of hypertonic solutions in the blood stream has been investigated both in normal 1-5 and in shocked animals, 6 , 7 In all instances there occurs a temporary blood dilution which is diminished in hemorrhagic shock 8 and increased in dehydration. 8 During an investigation of the local fluid loss resulting from trauma, a pressure phenomenon was noted following the injection of hypertonic electrolyte solutions into the arterial system. This study constitutes a preliminary report of this phenomenon with particular reference to its nature and basic mechanism.

Dogs weighing from 10 to 15 kg. were used. Nembutal was the basic anesthetic. The right and left femoral arteries and veins were exposed and, also, in several experiments, the brachial arteries. The arterial blood pressure was recorded from the carotid artery by the usual methods. The following solutions were utilized: (1) 25% sodium chloride solution; (2) 50% glucose solution; (3) 30% gum. acacia dissolved in 0.9% sodium chloride solution; (4) 50% sucrose solution. The quantity of solution used in each experiment was 5 to 10 cc. A series of 20 experiments was performed.

The intraärterial injection of hypertonic solutions results in an elevation of the systolic blood pressure from 10 to 50 mm. Hg. above the initial level. The duration of this pressor response is from 1 to 3 hours or even longer. The effectiveness of the solutions varies. Sodium chloride solutions produced the most prolonged elevation of blood pressure, whereas solutions of gum acacia had little, if any, result. Control solutions of isotonic sodium chloride did not increase the blood pressure. Certain other local and general effects were noted during and following the administration of these hypertonic solutions.