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Administration of sevoflurane using other agent-specific vaporizers
1Department of Child Health and Anesthesiology, The University of Missouri, Columbia 65212, USA.
American Journal of Therapeutics
|March 31, 1999
Summary
This study found that enflurane vaporizers can deliver clinically useful sevoflurane concentrations. This may enable sevoflurane use in resource-limited settings when specialized vaporizers are unavailable.
Area of Science:
- Anesthesiology
- Pharmacology
Background:
- Sevoflurane is a widely used inhalation anesthetic.
- Standard anesthetic vaporizers are agent-specific, designed for agents like halothane, isoflurane, and enflurane.
- The availability of sevoflurane vaporizers may be limited in certain regions.
Purpose of the Study:
- To determine the achievable concentrations of sevoflurane when administered through standard halothane, isoflurane, and enflurane vaporizers.
- To evaluate the impact of different gas flow rates on sevoflurane delivery.
- To assess the potential for using non-sevoflurane vaporizers in specific clinical scenarios.
Main Methods:
- An artificial lung analog model was utilized with a 3-L reservoir bag and anesthesia circle system.
- Ventilation parameters included oxygen and air at 2 L/min each (total 4 L/min), tidal volume of 800 mL, rate of 10 breaths/min, and I:E ratio of 1:2.
- Sevoflurane concentrations were measured after 10-minute equilibration periods with vaporizer settings increased incrementally from 1% to 5% (halothane/isoflurane) or 7% (enflurane).
- Studies were repeated with total gas flow increased to 8 L/min.
Main Results:
- Using halothane and isoflurane vaporizers at their maximum settings (5%), achieved sevoflurane concentrations were 3.0% and 3.1%, respectively.
- The enflurane vaporizer at its maximum setting (7%) delivered a maximum sevoflurane concentration of 6%.
- Increasing total gas flow from 4 L/min to 8 L/min significantly decreased sevoflurane concentrations across all tested vaporizers and settings.
Conclusions:
- Clinically useful concentrations of sevoflurane can be achieved using an enflurane vaporizer.
- While not routinely recommended, this method may offer a viable option for sevoflurane administration in resource-limited settings where specialized vaporizers are unavailable.
- The findings suggest a potential workaround for sevoflurane delivery in specific, low-resource circumstances.