Aqueous oxygen: A highly O₂-supersaturated infusate for regional correction of hypoxemia and production of hyperoxemia

Background: High levels of hyperoxemia may have utility in the treatment of regional tissue ischemia, but current methods for its implementation are impractical. A catheter-based method for infusion of O₂, dissolved in a crystalloid solution at extremely high concentrations, ie, 1 to 3 mL O₂/g (aqueous oxygen [AO]), into blood without bubble nucleation was recently developed for the potential hyperoxemic treatment of regional tissue ischemia. Methods and Results: To test the hypotheses that hypoxemia is correctable and that hyperoxemia can be produced locally by AO infusion, normal saline equilibrated with O₂ at 3 MPa (30 bar; 1 mL O₂/g) was delivered into arterial blood in two different animal models. In 15 New Zealand White rabbits with systemic hypoxemia, AO was infused into the midabdominal aorta at 1 g/min. Mean distal arterial PO₂ increased to 236±113 and 593±114 mm Hg on 1-hour periods of air and O₂ breathing, respectively, from a baseline of 70±10 mm Hg (P<.01). In contrast, infusion of ordinary normal saline in a control group (n=7) had no effect on arterial PO₂. No differences between groups (P>.05) in temporal changes in blood counts and chemistries were identified. In 10 dogs, low coronary blood flow in the circumflex artery was delivered with a roller pump through the central channel of an occluding balloon catheter. Hypoxemic, normoxemic, and AO- induced hyperoxemic blood perfusates (mean Po₂, 52±4, 111±22, and 504±72 mm Hg, respectively) were infused for 3-minute periods in a randomized sequence. Short-axis two-dimensional echocardiography demonstrated a significant decrease (P<.05) in left ventricular ejection fraction compared with baseline physiological values with low-flow hypoxemic and normoxemic perfusion but not with low-flow hyperoxemic perfusion. Conclusions: Intra- arterial AO infusion was effective in these models for regional correction of hypoxemia and production of hyperoxemia.