Anaphylactic Shock A Form of Distributive Shock without Inhibition of Oxygen Consumption

Background: The pathophysiology of anaphylactic shock during anesthesia is incompletely characterized. It is described as distributive by analogy with septic shock (anaerobic metabolism, high tissue oxygen pressure [PtiO 2 ] values). The PtiO 2 profile and its metabolic consequences during anaphylaxis are not known. Methods: Ovalbumin-sensitized anaphylactic shock rats (n ‫؍‬ 11) were compared to nicardipine-induced hypotension rats (n ‫؍‬ 12) for systemic hemodynamics, PtiO 2 , sympathetic nervous system activation, skeletal muscle blood flow, and interstitial lactate and pyruvate concentrations using combined microdialysis and polarographic Clark-type oxygen probes. Results: In both groups, the time course and the magnitude of arterial hypotension were similar. The ovalbumin group but not the nicardipine group displayed decreased skeletal muscle blood flow (from 45 ؎ 6.2 ml ⅐ 100 g ؊1 ⅐ min ؊1 to 24.3