Jf. Boylan et al., COCAINE TOXICITY AND ISOFLURANE ANESTHESIA - HEMODYNAMIC, MYOCARDIAL METABOLIC, AND REGIONAL BLOOD-FLOW EFFECTS IN SWINE, Journal of cardiothoracic and vascular anesthesia, 10(6), 1996, pp. 772-777
Citations number
23
Categorie Soggetti
Anesthesiology,"Peripheal Vascular Diseas","Cardiac & Cardiovascular System
Objectives: Increasing numbers of people use cocaine recreationally an
d may require anesthesia care, having recently abused the drug. Howeve
r, no data currently exist concerning potential interactions between t
oxic levels of cocaine and volatile anesthetic agents. This study inve
stigated the effects of cocaine infusion on systemic hemodynamics, myo
cardial metabolism, and regional organ blood flow in relation to depth
of isoflurane anesthesia. Design: Prospective, randomized, controlled
trial. Setting: A laboratory at a university medical center. Particip
ants: Twelve miniature pigs. Interventions: An open-chest swine model
was used. Isoflurance (ISO) was the sole anesthetic, administered at 0
.75 and 1.5 minimum alveolar concentration (MAC), and cocaine was infu
sed (n = 6) at a rate of 0.5 mg/kg/min. Control animals (n = 6) receiv
ed an equivalent amount of normal saline. Measurements and Main Result
s: Systemic and pulmonary arterial pressures and thermodilution cardia
c output data were collected at 0.75 MAC and 1.5 MAC ISO. Regional myo
cardial and blood flows to other organs were measured using radiolabel
ed microspheres. Arrhythmias and altered ventricular conduction were n
oted only in the cocaine group, along with significant elevations in d
iastolic arterial pressure, coronary perfusion pressure, and systemic
vascular resistance. Increased subendocardial blood flow occurred duri
ng cocaine infusion (p = 0.03); subepicardial perfusion was unchanged.
Cerebral (p < 0.01) and spinal cord (p < 0.05) blood flows were reduc
ed in animals receiving cocaine. Other organ blood flows were unchange
d with depth of anesthesia or cocaine administration, with the excepti
on of splenic blood flow (p < 0.04). Conclusions: Moderately toxic coc
aine levels occurring during isoflurane at 0.75 MAC and 1.5 MAC are as
sociated with hemodynamic abnormalities, a marked increase in systemic
vascular resistance, and a tendency to produce cardiac arrhythmias. A
reversal of endo/epicardial myocardial perfusion ratio occurs associa
ted with cocaine infusion during ISO anesthesia. This is probably not
related to a primary redistribution of subendocardial blood flow and m
ay be related to a combination of increased myocardial oxygen demand a
nd epicardial coronary vasoconstriction. The reductions in cerebral an
d spinal cord perfusion observed may explain, in part, the neurologic
sequelae of cocaine toxicity. Copyright (C) 1996 by W.B. Saunders Comp
any