The hemodynamic effects of cocaine during acute controlled hemorrhage in conscious rats

Background: Cocaine is often associated with trauma; however, little is kno wn about how its use alters the response to blood loss. The effect of cocai ne on hemodynamics following acute hemorrhage was studied in a rat model. M ethods: Following baseline measurements, rats were administered either intr avenous cocaine, or saline as a control. Both groups then underwent arteria l catheter hemorrhage of 30% of total blood volume. Outcome variables inclu de blood pressure, heart rate, hematocrit, pH, PCO2, PO2, and serum bicarbo nate. Results: Following hemorrhage, blood pressure decreased in both group s but the hypotension was significantly greater in the saline group than th e intravenous cocaine group at 0 and 5 minutes posthemorrhage. Heart rate w as increased significantly for the intravenous cocaine group compared to th e saline group starting at 15 minutes postcocaine and lasting for the next 25 minutes. No difference was noted for hematocrit, pH, PO2, or serum bicar bonate. Conclusion: Although transient, cocaine blunted the hypotensive res ponse to acute controlled hemorrhage and resulted in tachycardia.