Effects of cocaine in an experimental model of traumatic brain injury.
BACKGROUND
Cocaine intoxication is found in a significant subset of emergency department (ED) patients presenting with traumatic brain injury (TBI).


OBJECTIVE
To investigate the effects of acute cocaine intoxication on physiologic and metabolic parameters in a model of experimental TBI.


METHODS
Under inhalational anesthesia, swine were instrumented and subjected to fluid percussion TBI of 3 atm. Two groups were studied: TBI and cocaine (n = 7) and TBI only (n = 7). Two sequential doses of cocaine hydrochloride were administered intravenously to the animals receiving cocaine: 4 mg/kg 10 minutes prior to injury and 2 mg/kg 1 minute prior to injury. Control animals received normal saline. Cardiorespiratory and cerebral physiologic data were monitored for 180 minutes following injury. Cerebral blood flow (CBF) was measured using dye-labeled microspheres. Serum cocaine levels were measured by gas chromatography/mass spectrometry.


RESULTS
Mean (+/- SD) cocaine levels at the time of injury were 1,771 (+/- 403) ng/mL. All animals survived the 180-minute observation period. There was a trend toward higher intracranial pressure (ICP) in the control (15.4 +/- 8.2) vs. cocaine-treated (11.1 +/- 5.8) animals, although this did not reach statistical significance (p = 0.18). Cerebral venous lactate (CVL) levels also trended higher in the control (1.14 +/- 0.22) vs. cocaine-treated (0.91 +/- 0.19) groups (p = 0.06). Cerebral perfusion pressures (CPPs), however, did not differ between groups. The CBF values decreased significantly from baseline in both groups but were not different between groups.


CONCLUSIONS
Cocaine-intoxicated animals subjected to TBI showed no significant difference in primary outcome measures of CPP or CBF, although a nonsignificant trend toward lower ICP was noted. Overall, acute cocaine intoxication did not adversely affect the physiologic parameters examined in this TBI model.
McBeth
Brian D
BD
University of Michigan, Ann Arbor, MI, USA. brian.d.mcbeth@healthpartners.com
Stern
Susan A
SA
Wang
Xu
X
Mertz
Michelle
M
Zink
Brian J
BJ
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001930:Brain Injuries / Q000097:blood / Q000150:complications*; D002302:Cardiac Output / Q000187:drug effects; D002560:Cerebrovascular Circulation / Q000187:drug effects; D019970:Cocaine-Related Disorders / Q000097:blood / Q000150:complications*; D004195:Disease Models, Animal; D007427:Intracranial Pressure / Q000187:drug effects; D019344:Lactic Acid / Q000097:blood; D012016:Reference Values; D012079:Renal Circulation / Q000187:drug effects; D013552:Swine
D019344:Lactic Acid