Neurobehavioral and physiologic effects of trifluoromethane in humans

S. C. Fagan, A. A. Rahill, G. Balakrishnan, J. R. Ewing, Craig A. Branch, G. G. Brown

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Nuclear magnetic resonance (NMR) imaging shows promise in the measurement of human cerebral blood flow (CBF) in that nonradioactive indicators may be used. Our earlier investigations with trifluoromethane (FC-23) gas have shown that this compound can be used to safely and effectively measure CBF in anesthetized animal models. In this Phase I dose-escalation study we set out to determine the maximal tolerated concentration (MTC) of FC-23 in normal healthy male volunteers and to assess its feasibility as an NMR indicator. Five subjects were exposed in a blinded fashion to escalating concentrations of FC-23 between 10% and 60%, randomly interleaved with exposures to both room air and 40% nitrous oxide. On each study day, the subjects breathed the test gas for eight pulses of 3 min each with 2-min clearance periods between the pulses. The subjects underwent intensive physiologic and neurobehavioral monitoring throughout the study period. The first subject experienced an anesthetic response to 60% FC-23, and the second subject experienced 'discomfort' and requested discontinuation at the initiation of 40% FC-23. The MTC was subsequently determined to be 30% FC-23 (all subjects tolerated the gas), although a small (37.6 vs. 40.5) but statistically significant retention of carbon dioxide was found (p = .003). When one subject received 30% FC-23 during an NMR imaging study, a pronounced anesthetic effect with intolerable hyperacusis was demonstrated. Human studies of FC-23 have been discontinued in our laboratory.

Original languageEnglish (US)
Pages (from-to)221-229
Number of pages9
JournalJournal of Toxicology and Environmental Health
Volume45
Issue number2
StatePublished - 1995
Externally publishedYes

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Anesthetics
Nuclear magnetic resonance
Blood
Gases
Imaging techniques
Cerebrovascular Circulation
Carbon dioxide
Animals
Magnetic Resonance Spectroscopy
Oxides
Monitoring
Healthy Volunteers
Air
Hyperacusis
Magnetic Resonance Imaging
fluoroform
Nitrous Oxide
Physiologic Monitoring
Carbon Dioxide
Animal Models

ASJC Scopus subject areas

  • Pollution
  • Toxicology

Cite this

Fagan, S. C., Rahill, A. A., Balakrishnan, G., Ewing, J. R., Branch, C. A., & Brown, G. G. (1995). Neurobehavioral and physiologic effects of trifluoromethane in humans. Journal of Toxicology and Environmental Health, 45(2), 221-229.

Neurobehavioral and physiologic effects of trifluoromethane in humans. / Fagan, S. C.; Rahill, A. A.; Balakrishnan, G.; Ewing, J. R.; Branch, Craig A.; Brown, G. G.

In: Journal of Toxicology and Environmental Health, Vol. 45, No. 2, 1995, p. 221-229.

Research output: Contribution to journalArticle

Fagan, SC, Rahill, AA, Balakrishnan, G, Ewing, JR, Branch, CA & Brown, GG 1995, 'Neurobehavioral and physiologic effects of trifluoromethane in humans', Journal of Toxicology and Environmental Health, vol. 45, no. 2, pp. 221-229.
Fagan, S. C. ; Rahill, A. A. ; Balakrishnan, G. ; Ewing, J. R. ; Branch, Craig A. ; Brown, G. G. / Neurobehavioral and physiologic effects of trifluoromethane in humans. In: Journal of Toxicology and Environmental Health. 1995 ; Vol. 45, No. 2. pp. 221-229.
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