A marked and prolonged increase in flow follows the passage of a gas embolus through the arteries of a limb. The mechanism by which a gas embolus produces such a vasodilation is not understood; and, despite, several clinical trials, there is still controversy over the clinical role of such intra-arterial injections.1-13 In this paper, we will describe the results of an investigation into the nature, site, and characteristics of the vasodilation. Our clinical experience with 38 patients with occlusive arterial lesions who have received intra-arterial injections of gaseous oxygen will also be reported.
A. Laboratory Investigation.
—Sixty-three mongrel dogs weighing from 15 to 25 kg were anesthetized with 35 mg/kg of intravenous sodium pentobarbital, with small additional doses as needed. They breathed room air via an endotracheal tube. Clotting was controlled by 2 mg/kg of intravenous heparin with an addition 1 mg/kg every 90 minutes thereafter. They rested