The output of four modern vaporizers in the presence of helium

Robert G. Loeb

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


It has been previously demonstrated that the output of calibrated vaporizers is influenced by the concentration of nitrous oxide in the carrier gas. This study was performed to determine whether helium in the carrier gas affects the output of modern calibrated vaporizers. A factorial design was used to determine the influence of carriergas helium concentration, carriergas flow rate and vaporizer dial setting on the output of four vaporizers: Ohio Calibrated Enflurane, Ohio Calibrated Isoflurane, Ohmeda Isotec 4, and Dräger Vapor 19.1 Isoflurane. Three vaporizers of each model were tested. Output was converted to % of baseline so that different dial settings could be compared. For a given dial setting, baseline was defined as the output at a carriergas flow rate of 3 L · min-1 and helium concentration of zero. The data were analyzed using multiple linear regression. There was an effect of helium concentration on vaporizer output in all models. None of these changes was clinically important, since vaporizer output did not vary by more than ± 10%, except at high flows and at high helium concentrations with the Ohmeda Isotec 4. It is concluded that these vaporizers can be used safely with helium.

Original languageEnglish (US)
Pages (from-to)888-891
Number of pages4
JournalCanadian Journal of Anaesthesia
Issue number8
StatePublished - Oct 1992
Externally publishedYes


  • equipment: vaporizers
  • gases, nonanaesthetic: helium

ASJC Scopus subject areas

  • Anesthesiology and Pain Medicine


Dive into the research topics of 'The output of four modern vaporizers in the presence of helium'. Together they form a unique fingerprint.

Cite this