Abstracts

Abstracts in this issue were

prepared by residents in the

University of Arizona Emergency

Medicine Residency Program.

Richard Dart, MD, PhD

Co-Editor

Section of Em.ergeney Medicine

University of Arizona College

of Medicine

Tucson, Arizona

Vincent J Markovchick, MD,

FACEP

Co-Editor

Emergency Medical Services

Denver General Hospital

Denver, Colorado

William A Robinson, MD, FACEP

Co-Editor

Department of Emergency

Medicine

University of Missouri-Kansas City

School of Medicine

Kansas City, Missouri

cocaine, pregnancy

Pregnancy enhances cardiotoxicity of cocaine: Role of progesterone Sharma A, Plessinger MA, Sharer DM, et al

Toxicol Appl Pharmacol 113.30-35 Mar 1992

This study evaluated the effects of pregnancy on the cardiotoxicity of cocaine. Isolated papillary muscles from three groups of rats {pregnant; nonpregnant; and progesterone- treated, nonpregnant) were exposed to increasing doses of cocaine (range, 10 -16 to l g -°4 M). These doses are similar to those achieved in human exposures. The papillary muscles from the nonpregnant group of rats showed an initial positive inotropic response, which, as the cocaine dose was increased, was followed by a negative inotropic response. The papillary muscles from the other two groups showed only a negative inotropic response to cocaine and became completely nonfunctional at doses one to four orders of magnitude lower than the nonpregnant group. The authors conclude that pregnancy enhances the cardiotoxicity of cocaine and that progesterone may be the mediator of this phenomenon.

Andrea Graebe, MD

dexamethasone

Effects of treatment with dexamethasone on recovery Dutka A J, Mink RB, Pearson RR, et el Undersea Biomedical Research

19:131-141 Mar 1992

Dexamethasone is often recommended in the treatment of serious central nervous system decompression accidents. The authors prospectively studied pro- phylactic and therapeutic adminis- tration of dexamethasone combined with hyperbaric treatment in anes- thetized dogs subjected to carotid air embolism and a brief episode of hypertension. Animals were divided randomly into three groups and received dexamethasone both before and after introduction of air embolism (group 1), after air embolism only (group 2), or IV saline and no dexamethasone (control). All animals then underwent decompres- sion in a hyperbaric chamber during which they had transient hyperten- sion induced by norepinephrine, a stimulus designed to reproduce secondary effects previously identi- fied with cerebral embolic injuries. The authors evaluated hemodynamic parameters, somatosensory-evoked potential, cerebral blood flow, and brain edema to assess the efficacy of dexamethasone. Results indicated some transient differences between groups during hyperbaric treatment,

but the ultimate outcome for all groups failed to demonstrate any significant improvement in recovery of bioelectric function, reduction in intracranial pressure, or cerebral edema. The authors were unable to conclude that dexamethasone improved recovery after cerebral arterial gas embolism.

Mark Maheney, MD

clonidine

Clonidine for patients with rapid atrial . f ibrillation Roth A, Kaluski E, Feiner S, et el Ann Intern Med 116:388-390 Mar 1992

Clonidine is a selective, centrally acting a-2-agonist used to treat hypertension. This randomized, con- trolled trial evaluated the use of clonidine to slow the ventricular rate in hemodynamically stable patients with rapid atrial fibrillation. The sample consisted of 18 consecutive patients who presented to the emer- gency department for the primary evaluation and treatment of atrial fibrillation and who were considered clinically and hemodynamically sta- ble. Exclusion criteria included acute or terminal illness; current use of antiarrhythmic agents, calcium- channel blockers, or g-blockers; excessive hypertension; pulmonary, vascular, or pericardial disease; and electrolyte imbalance. Patients were assigned randomly to receive no

1 6 4 / 1 0 1 2 ANNALS OF EMERGENCY MEDICINE 21:8 AUGUST 1992