Abstract

Several theories have been proposed, but the etiology and pathway of neural transmission for the sensation of tourniquet pain remain unknown. This study was designed to observe the circulatory response and to measure the stress response markers associated with maintenance of tourniquet inflation in an anesthetized primate model. Eight African Green monkeys ( Cercopithecus aethiops ) were anesthetized, and heart rate (HR) and systolic and diastolic blood pressure (SBP and DBP) were measured every five minutes. In each animal, a control trial without tourniquet inflation was compared to an experimental trial with tourniquet inflation on the left lower extremity to 300 mmHg for a period of 90 minutes. After maintenance of tourniquet inflation for a period of 30-45 minutes, each animal demonstrated a gradual, progressive increase in HR, SBP and DBP as compared to preinflation baseline values ( p < 0.05). An increase in serum cortisol and plasma norepinephrine was demonstrated to correlate with the circulatory response in this model. The results of this study suggest that the circulatory response to maintenance of tourniquet inflation in this animal model may be mediated by a neurohumoral response to tourniquet pain and that an animal model may be appropriate for further studies into the etiology and neural pathways associated with the sensation of tourniquet pain.