Faculty Collaboration Database

Laser-Doppler measurement of the effects of halothane and isoflurane on the cerebrovascular CO2 response in the rat. Anesth Analg 1995 Apr;80(4):696-702

Date

04/01/1995

Pubmed ID

7893020

DOI

10.1097/00000539-199504000-00008

Scopus ID

2-s2.0-0028951335 (requires institutional sign-in at Scopus site)   28 Citations

Abstract

We used laser-Doppler flowmetry to compare the effects of the volatile anesthetics, isoflurane and halothane, on the cerebrovascular response to CO2 inhalation in male Sprague-Dawley rats. The effects of 0.5 and 1.5 minimum alveolar anesthetic concentrations (MAC) of halothane and isoflurane on the microcirculatory response to CO2 were compared at 22, 36, and 66 mm Hg end-tidal partial pressure of carbon dioxide (ETCO2). An additional group of animals was anesthetized by continuous barbiturate infusion (10-20 mg.kg-1.h-1). Arterial blood pressure was maintained at control levels throughout the experiment using an infusion of phenylephrine (0.5-5 micrograms.kg-1.min-1). Laser-Doppler flow (LDF) was greater at 1.5 MAC than at 0.5 MAC at each ETCO2 for both anesthetics. The CO2 reactivity (percent LDF change/mm Hg change ETCO2) from hypocapnia to normocapnia was similar to that from normocapnia to hypercapnia. CO2 reactivity with barbiturate infusion and 0.5 MAC isoflurane were 1.78 +/- 0.19 and 2.28 +/- 0.22 (no difference), respectively, both being greater than that with 0.5 MAC halothane at 1.19 +/- 0.14 (P < 0.05). A similar difference was suggested at 1.5 MAC halothane and 1.5 MAC isoflurane (1.99 +/- 0.25 and 2.67 +/- 0.35, respectively). The CO2 reactivity was greater at 1.5 MAC halothane compared to 0.5 MAC halothane. The results of this study suggest that an increase in arterial CO2 may increase cerebrocortical red cell flow more with isoflurane than with halothane, at least at moderate anesthetic concentrations.

Author List

Lee JG, Smith JJ, Hudetz AG, Hillard CJ, Bosnjak ZJ, Kampine JP

Author

Cecilia J. Hillard PhD Associate Dean, Center Director, Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Anesthesia
Animals
Carbon Dioxide
Cerebrovascular Circulation
Halothane
Isoflurane
Laser-Doppler Flowmetry
Male
Pentobarbital
Rats
Rats, Sprague-Dawley