A technique to depress desflurane vapor pressure

Research output: Contribution to journalArticle

Abstract

Objective: To determine whether the vapor pressure of desflurane could be decreased by using a solvent to reduce the anesthetic molar fraction in a solution (Raoult's Law). We hypothesized that such an anesthetic mixture could produce anesthesia using a nonprecision vaporizer instead of an agent-specific, electronically controlled, temperature and pressure compensated vaporizer currently required for desflurane administration. Animal: One healthy adult female dog. Procedure and results: Propylene glycol was used as a solvent for desflurane, and the physical characteristics of this mixture were evaluated at various molar concentrations and temperatures. Using a circle system with a breathing bag attached at the patient end and a mechanical ventilator to simulate respiration, an in-circuit, nonprecision vaporizer containing 40% desflurane and 60% propylene glycol achieved an 11.5% ± 1.0% circuit desflurane concentration with a 5.2 ± 0.4 (0 = off, 10 = maximum) vaporizer setting. This experiment was repeated with a dog attached to the breathing circuit under spontaneous ventilation with a fresh gas flow of 0.5 L minute-1. Anesthesia was maintained for over 2 hours at a mean vaporizer setting of 6.2 ± 0.4, yielding mean inspired and end-tidal desflurane concentrations of 8.7% ± 0.5% and 7.9% ± 0.7%, respectively. Conclusions and clinical relevance: Rather than alter physical properties of vaporizers to suit a particular anesthetic agent, this study demonstrates that it is also possible to alter physical properties of anesthetic agents to suit a particular vaporizer. However, propylene glycol may not prove an ideal solvent for desflurane because of its instability in solution and substantial-positive deviation from Raoult's Law.

Original languageEnglish (US)
Pages (from-to)275-280
Number of pages6
JournalVeterinary Anaesthesia and Analgesia
Volume33
Issue number5
DOIs
StatePublished - Sep 2006

Fingerprint

Vapor Pressure
Nebulizers and Vaporizers
vapor pressure
anesthetics
propylene glycol
breathing
Propylene Glycol
Anesthetics
physical properties
anesthesia
Respiration
ventilators
dogs
methodology
Anesthesia
bags
temperature
Dogs
gases
Temperature

Keywords

  • Azeotrope
  • Boiling point
  • Colligative properties
  • Desflurane
  • I-653
  • Raoult's Law

ASJC Scopus subject areas

  • veterinary(all)

Cite this

A technique to depress desflurane vapor pressure. / Brosnan, Robert J; Pypendop, Bruno H.

In: Veterinary Anaesthesia and Analgesia, Vol. 33, No. 5, 09.2006, p. 275-280.

Research output: Contribution to journalArticle

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